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CCIAP Project A-804
Impacts of Storms & Winds on Transportation in Southwestern Newfoundland
Norm Catto; Geography, Memorial University
Dale Foote, Dermot Kearney; Environment Canada
Wade Locke; Economics, Memorial University
Brad DeYoung; Physics & Physical Oceanography, Memorial University
Evan Edinger; Geography, Memorial University
Dan Ingram, Jeff Karn; Environmental Science, Memorial University
Jennifer Straatman; Geography, Memorial University
2006
1
CCIAP Project A-804
Impacts of Storms & Winds on Transportation in Southwestern Newfoundland
Table of Contents
Introduction …………………………………………………………………….. 1
Geomorphic Impacts of Waves and Storms on the Southwestern
Coastline of Newfoundland, including Port-aux-Basques Harbour ………… 12
Analysis of Tidal and Storm Surge record at Port aux Basques Harbour …. 28
Records and Physical Impact of Wreckhouse Events ……………………….. 54
Climate and Meteorological Analyses ………………………………………… 63
The Value of Economic Loss Associated with Weather-Related Delays
on the North Sydney-Port aux Basques Marine Transportation Link
in 2003 and 2004 ………………………………………………………... 112
Summary and Discussion ………………………………………………………. 117
References ………………………………………………………………………. 124
Appendix A: Station Histories ………………………………………………… 134
Appendix B: Seasonal Graphs ………………………………………………… 136
Appendix C: Wind Rose Diagrams ……………………………………………. 144
- 1 -
Impacts of Storms & Winds on Transportation in Southwestern Newfoundland
CCIAP Project A-804
Norm Catto; Geography, Memorial University
Dale Foote, Dermot Kearney; Environment Canada
Wade Locke; Economics, Memorial University
Brad DeYoung; Physics & Physical Oceanography, Memorial University
Evan Edinger; Geography, Memorial University
Dan Ingram, Jeff Karn; Environmental Science, Memorial University
Jennifer Straatman; Geography, Memorial University
1. Introduction
One of the key questions for transportation throughout Newfoundland is whether
storm and wind activity is increasing, in frequency or magnitude or both. Other locations
around the Atlantic Ocean have shown differing results, with some areas influenced by
increased storminess and others showing no change over the past 50 years, thus making
extrapolation to eastern Canada impossible.
All of the island of Newfoundland is dependent on maintaining regular Marine
Atlantic ferry service through the harbour at Channel-Port aux Basques. All road traffic
for the remainder of the island must pass along the Trans-Canada Highway from Port aux
Basques northeast to Corner Brook through the Wreckhouse area, noted for its strong
winds (“Wreckhouse Events”). At present, storm activity causes disruptions to ferry
operations at Port-aux-Basques, with ships compelled to remain at anchor outside the
harbour for two days or more, unable to dock until the wind subsides. During storm or
wind events, transport truck traffic is unable to travel along the Trans-Canada Highway
through the Wreckhouse area, as wind strength is sufficient to overturn large vehicles.
Increased storm severity and/or frequency would result in increased disruption to
both ferry and road traffic. Without a better understanding of the likelihood of increases
in either storm frequency or magnitude, Marine Atlantic and trucking operators are
unable to adapt effectively to the uncertain impact of climate variability. This uncertainty
ultimately affects all residents of Newfoundland who are dependent on this major land
2
and harbour transportation link. Transportation in this key region of southwest
Newfoundland is thus vulnerable to disruption from both storm surge and wave-induced
damage at the ferry terminal, and from wind events interfering with highway traffic.
1.1 Objectives
The objectives of this research directly related to marine storm events were:
• Assessment of the frequency and magnitude of extreme storm surges and high
tide events in southwest Newfoundland
• Documentation of decadal- to century-scale change in sea level, storm surges,
and extreme high tide events caused by climate change and variation
• Determination of the vulnerability of Channel-Port aux Basques, and the Marine
Atlantic ferry terminal in particular, to future extreme storm surges and high
tide events
The objectives directly related to highway transportation, as well as marine service,
were:
• Assessment of the frequency, magnitude, and wind direction of extreme wind
events in southwest Newfoundland
• Documentation of decadal- to century-scale change in extreme wind events
caused by climate change and variation
• Determination of the vulnerability of transportation infrastructure in southwest
Newfoundland to extreme wind events
Investigations to accomplish these objectives within CCIAP Project A-804 were
divided into the following components:
1. Co-ordination and community liaison (Catto)
2. Geomorphic Impacts of Waves and Storms on the Southwestern Coastline of
Newfoundland, including Port aux Basques Harbour (Catto, Ingram, Edinger)
3
3. Analysis of Tidal and Storm Surge record at Port aux Basques Harbour (Ingram,
DeYoung, Catto, Edinger)
4. Record and Impact of Wreckhouse Events (Catto, Straatman, Foote, Kearney)
5. Climate and Meteorological analysis (Foote and Kearney, with contributions as
acknowledged)
6. Economic impact analysis (Locke)
This report is organized to discuss each of these components. Chapter 1 introduces
the study region. Geomorphic impacts of waves and storms on the coastline, and in Port
aux Basques Harbour, are considered in Chapter 2. Analysis of the tidal and storm surge
activity at Port aux Basques Harbour is presented in Chapter 3. The record and physical
impacts of Wreckhouse events are discussed in Chapter 4. The climate and
meteorological data are analysed in Chapter 5. Economic impact analysis is presented in
Chapter 6. The results are summarized and discussed in Chapter 7.
1.2 Study Region
Investigation focused on the area of southwestern Newfoundland extending from
Channel-Port aux Basques to Wreckhouse (Fig. 1.1, 1.2). The communities of Channel
and Port-aux-Basques were amalgamated in 1945 to form a single community, officially
named ‘Channel-Port aux Basques’ but commonly referred to as Port aux Basques. In
2001, the population of Channel-Port aux Basques was 4,637, an 11.6% decline since
1996 (http://www12.statcan.ca/english/profil01). The declining population reflects a
general limitation of economic opportunity in southwestern Newfoundland, a trend which
has continued since 2001 (Government of Newfoundland and Labrador, 2005).
Port aux Basques has served as a harbour since the early 1500s. It was chosen as
the main ferry port and terminus for the Newfoundland Railway in 1898, and has served
as the main surface entry point to Newfoundland since that time. Construction of the
Trans-Canada Highway (completed in 1965) eventually rendered rail service redundant,
with passenger service ceasing in 1971 and freight service in 1988. Port aux Basques
4
Cape North
North Sydney
BurgeoChannel Port-aux-Basques
Cape Ray
Cabot Strait
Gulf of St. Lawrence
N
0 25 km
Figure 1-1: Satellite image of the Cabot Strait (NASA, 2002) and its location in relation to Atlantic Canada (inset; NRCan, 2005).
remains central to the Newfoundland economy, however, by virtue of its position at the
terminus of the Trans-Canada Highway in Newfoundland, and as the only port which has
year-round ferry service to the island.
Marine Atlantic operates a total of four ships between Port-aux-Basques and
North Sydney NS (Figure 1.1). Currently, three large ferries (M.V. Caribou, M.V. Joseph
and Clara Smallwood, and M.V. Leif Ericson) run continuously during the peak season
(generally from June to September) and two remain in service for the whole year. The
5
Figure 1-2: Aerial photograph of Port-aux-Basques Harbour (circa 1983). Note the ferry docked at the wharf (top left) and the orientation of the breakwater structures (photo from Government of Newfoundland and Labrador). M.V. Atlantic Freighter is dedicated to commercial traffic and freight, operating year-
round. From 2000 to 2004, the service transported an average of over 434,000
6
passengers annually (Marine Atlantic, 2005), and in 2005, an estimated 500,000 people
used Marine Atlantic’s ferry service through the port.
The Trans-Canada Highway extends northwestward from Port aux Basques,
paralleling the coast. The small coastal community of Cape Ray is accessed from the
highway, as is JT Cheeseman Provincial Park. Northwest of Cape Ray, the highway
turns northeast, passing through the Wreckhouse area flanked by Table Mountain, Sugar
Loaf, Cook Stone Hill, and Red Rocks Hill (Figure 1.3). The Wreckhouse area has been
noted for its extremely strong wind events since initial construction of the Newfoundland
Railway. Disruptions to rail service were recorded, with cars and engines forced off the
tracks, and highway traffic is periodically disrupted at present. The Trans-Canada
Highway leaves the Wreckhouse area south of the small community of St. Andrews.
The combined Port aux Basques – Wreckhouse route currently represents the major
year-round surface transportation link between mainland Canada and the island of
Newfoundland. It is the only link for highway traffic. Disruptions of this route, either by
wave and storm surge activity at Port aux Basques or by strong Wreckhouse wind events,
have resulted in severing the supply line to the remaining 500,000 residents of the island
of Newfoundland, from St. Andrews to St. Anthony and St. John’s. Study of the
potential for future interruptions resulting from weather events, climate variability, or
long-term climate change, is thus of importance for all residents of the island of
Newfoundland.
1.3 Present Regional Climate
Southwestern Newfoundland lies within the West Coast climate zone of the
province (Banfield 1981, 1993; Damman, 1983). The area is under the influence of a
cool humid mid-boreal climate (modified Köppen-Geiger Dfb), a consequence of the
influence of the Gulf of St. Lawrence and the dominant southwesterly winds.
Climate data is collected in Port-aux-Basques by an automated weather station
located approximately 1 km west of the harbour on Base Road, in the Mouse Island area
(47° 34' N, 59° 09' W, 39.70 m asl; Environment Canada, 2005). Daily mean
temperatures vary between -5°C in February and 15°C in August (Environment Canada,
7
N 0 100 200 metres
Figure 1-3: Nautical chart of Port-aux-Basques Harbour. Note the breakwater structures and the narrow shipping lane (Canadian Hydrographic Service, 1998).
8
2005; Catto, 2002a, 2002c; Catto et al., 2006). Although mean February sea surface
temperatures are less than 0°C along the entire coastline (Markham, 1980), development
of sea ice is restricted (Cote, 1989), allowing all shorelines in southwesternmost
Newfoundland to be affected by waves and storm surges throughout the winter (Catto,
1994a, 1994b, 2002a, 2002b; Ingram, 2004). The beaches of southwestern
Newfoundland thus are subject to reworking and modification throughout the entire year.
Mean annual precipitation along the coastline is 1500 mm, with 1570 mm recorded
at the Port aux Basques station (Environment Canada, 2005), of which 15-25% falls as
snow (343 cm snowfall at Port aux Basques). Strong winds and periodic thaws limit the
mean annual duration of snow cover to less than 70 days in coastal areas, although snow
cover in the interior persists for up to 5 months annually. Statistically, the driest month is
April (mean monthly precipitation 90-100 mm), and the wettest months are November
and December (mean 140-155 mm during each). The combination of substantial
precipitation and low summer temperatures, however, result in limited evaporation during
the summer months. The excess of precipitation over evaporation locally exceeds 100%
during some summers, as well as throughout the winter months, creating a perhumid
moisture regime and allowing wetlands to develop.
During the spring and summer, from March to August, the prevailing winds are
easterly. During the autumn and winter, from September to February, the prevailing
direction is from the west. The mean annual wind speed is 24.4 km/h (Environment
Canada, 2005) and higher magnitude wind events are common. According to the 30-year
Canadian Climate Normals, an average of 69.5 days per year experience winds exceeding
52 km/h and an annual average of 33.6 days experience winds in excess of 63 km/h
(Environment Canada, 2005). Easterly winds tend to have the greatest influence on ferry
traffic into Port-aux-Basques Harbour, and are also primarily responsible for triggering
Wreckhouse wind events.
Detailed discussion of the data related to potential patterns of climate variation
and change over the past 50 years is presented in Chapter 5 of this report.
9
1.4 Harbour Configuration and Port Infrastructure
Port-aux-Basques Harbour is open to the southeast, with an embayment extending
northeastward at its head, and is approximately 2 km2 in area (Figure 1.2, 1.3). The
mouth of the harbour is 900 m wide at the seaward limit. The southeastward orientation
makes the harbour susceptible to winter easterly storms. This vulnerability has been
mitigated with the construction of a breakwater, consisting of two separate sections,
confining the opening midway through the channel. At its narrowest point, the channel
opening is less than 400 metres wide (Figure 1.3). The effectiveness of the breakwater is
enhanced by the presence of two natural islands, Vardys Island situated in the centre of
the inner section of the harbour, and Pikes Island to which the breakwater is joined. The
two islands form important buffers to wave action.
The Marine Atlantic ferry terminal is located at the northwestern corner of the
harbour, on the former Ford’s Island. which has been connected to the mainland to make
room for the terminal infrastructure. To the east of the ferry terminal, and along the
eastern shore, the harbour is largely undeveloped. To the south of the terminal, extending
outwards in the harbour, the shoreline has been extensively developed. Numerous
wharves, including the Federal Government Wharf, Ring Bolt Cove Wharf, a recreational
board walk outfitted with a performance stage and concession stands, the Port-aux-
Basques Harbour Authority Wharf, and the local fish plant facilities are present.
Additionally, the outer area of the harbour is lined with private property with homes
constructed very close to the shoreline; some only 1 m above the high water line.
The harbour underwent major infrastructure development and improvement in the
1950s in preparation for larger ships and increased traffic. Along with the construction of
a new terminal building, the parking area was expanded and a new wharf and breakwater
were built. The L-shaped pier had a total length of 317 metres and enabled the
simultaneous docking of the southern Newfoundland coastal boats, servicing Burgeo and
ports east, and the larger Nova Scotia ferries (Windsor, 1956). The harbour was dredged
in 1953.
Construction of the breakwater was completed in July 1956. The structure was
assessed to have essentially eliminated undertow in the docking area, and overall docking
conditions at the pier were estimated to have improved by 40%. The breakwater extends
10
134 m across the harbour and is 21 m wide. At the end of the structure the water is more
than 10 m deep. The breakwater rises about 6 m above the waterline (Windsor, 1956).
Figure 1-4: Port-aux-Basques Harbour looking southeast. Note the breakwater extending across the harbour and a section of the Marine Atlantic dock in the foreground. Vardys Island is to the left and to the right is the Transport Canada vessel traffic tower and headquarters (photo taken June 2005).
Figure 1-5: The town of Channel Port-aux-Basques and the west side of the harbour. Note the ship (M.V. Atlantic Freighter) docking at the Marine Atlantic ferry terminal and the proximity of some of the homes to the ocean. (photo taken June 2005).
11
0 1000 m
N
Tide gauge
Climate station
Figure 1-6: Topographic map of the Port-aux-Basques area. The locations of the automated tide gauge and climate station are identified with yellow circles and labelled (Geomatics Canada, 1986).
12
2. Geomorphic Impacts of Waves and Storms on the Southwestern Coastline of
Newfoundland, including Port-aux-Basques Harbour
Norm Catto, Dan Ingram, Evan Edinger
2.1 Introduction: Storm surges and sea level rise
Newfoundland, including the southwest coast, has been subjected to many
significant storms, resulting in property destruction (Forbes et al., 2000; Catto et al.,
2003; Catto and Hickman, 2004; Catto, 2006b). Hurricane Juan (2003), the most
economically destructive hurricane event in Atlantic Canadian history, killed eight people
and was responsible for at least $200 million in damage to Nova Scotia and Prince
Edward Island (Environment Canada, 2004). Historical events, such as the Great
Hurricane of 1775 in eastern Newfoundland (Stevens and Staveley, 1991; Stevens, 1995;
Ruffman, 1995) provide ample evidence of the impact of extreme storms and storm
surges.
The effectiveness of any particular storm at a location depends upon the angle of
wave attack, the number of previous events during the season, and other local factors.
Adjacent beaches can exhibit very different responses to a particular storm, as was
evident on southwestern Newfoundland beaches impacted by Hurricanes Gustav (2002)
and Frances (2004). Beaches separated only by a headland varied widely in the amount of
geomorphic response to storms (e.g. Catto et al., 2003).
The northern Atlantic Ocean has been undergoing an increase in hurricane
frequency and magnitude since 1995 (Goldenberg et al., 1997, 2001; Landsea et al.,
1998; Debernard et al., 2002; Emanuel, 2005; Webster et al., 2005). However, the
relationship between changes in hurricane frequency and magnitude, and increases in air
temperature or sea surface temperature (SST), is not clear at present, and consensus does
not exist. Although causal links between SST changes and hurricane frequency and
strength have been suggested (e.g. Sugi et al., 2002; Trenberth et al., 2003; Knutsen and
Tuyela, 2004; Trenberth, 2005), other researchers have expressed reservations and
recognized uncertainties (e.g. Swail, 1997; Shapiro and Goldenberg, 1998; Pielke et al.,
2005; Webster et al., 2005). Regardless of the uncertainty of future changes in hurricane
13
frequency and magnitude in response to climate change, it is apparent that the North
Atlantic is currently undergoing a period of increased hurricane activity.
A storm surge is defined as the elevation of the water resulting from
meteorological effects on sea-level (Murty,1984; Pugh, 1987) The storm surge elevation
is the difference between the observed water level during the storm and the level that the
astronomical high tide would normally rise to in the absence of storm activity (Forbes et
al., 2004). The Port-aux-Basques area has experienced surges of a variety of magnitudes,
including several large ones, over the past 100 years. The return time of a surge that
exceeds 1 m is approximately 10 years, and every 50 years a surge will occur that
exceeds 1.5 to 2 m (Charles O’Reilly, personal communication). The full effect of a
surge may not be experienced unless it coincides with high tide, particular a high spring
tide. Storm surges are associated with both winter storms (e.g. January 2000) and
summer tropical storm systems (e.g. Hurricane Gustav, 2002).
Rising sea level allows waves and storm surges to penetrate further inland,
modifying beach morphology and sedimentology and resulting in both coastal erosion
and damage to infrastructure. The observed changes in sea level result from the interplay
of climate change, involving melting of the polar glaciers, thermal expansion of the
ocean, and consequent increase in the water volume in the oceans, with isostatic response
to past glaciation. With the exception of northernmost Labrador and Lake Melville,
Atlantic Canada is now subsiding, resulting in relative sea level rise, transgression and
flooding by the ocean.
Short-term (decades) changes in sea level can be assessed through study of tide
gauge records. At Port aux Basques, the tide gauge record from 1960 through 2005
indicates a mean rate of sea level rise of approximately 3.3 mm/a (Fig. ccc). This rate is
comparable to those observed at Charlottetown and Halifax (e.g. Shaw et al. 1998, 2001;
Bruce, 2002; McCulloch et al., 2002) and in eastern Newfoundland (e.g. Catto, 2006b,
2006c; Catto et al., 2003). Evidence of marine transgression is reflected by enhanced
erosion along many Atlantic Canadian beaches, including those to the northwest of Port
aux Basques (Catto, 2002) and in the Burgeo area (Ingram, 2004), and inundation of
terrestrial peat deposits and trees.
14
In low-lying areas with coastal development, erosion and flooding are
significantly increasing and will continue to increase (Daigle et al., 2006). Consideration
of the geological factors, rate of sea level rise, amounts of coastal erosion, wave climate,
and tidal regime allow calculation of the sensitivity to sea-level rise of shoreline
segments (e.g. Gornitz et al., 1993). This assessment has been completed for Atlantic
Canada as a whole on a broad regional scale (Shaw et al., 1998), and more detailed
assessments have been conducted for specific segments of the coastline (e.g. Chmura et
al., 2001; Catto et al., 2003; Daigle et al., 2006; Shaw, 2006). The observed sea level
rise in Atlantic Canada, and the projected rise for the future, depends upon the interaction
between the changing volume of the oceans and glacioisostatic activity.
2.2 Storm Surge Events in Southwestern Newfoundland
The coastline of southwestern Newfoundland has been subject to at least 5 storm
surge events since January 2000. The largest of these was the storm surge of 21-22
January 2000, associated with the same event that caused substantial damage in Prince
Edward Island and New Brunswick (Forbes et al., 2000; Bruce, 2002; McCulloch et al.,
2002; Parkes et al., 2006). Among others, lesser surge events resulted from Hurricane
Gustav (12 September 2002) and Hurricane Frances (2 September 2004).
The largest storm surge in recent years to affect the Port aux Basques region
occurred on 21-22 January 2000. Unfortunately, the precise magnitude of the surge
cannot be determined in Port aux Basques Harbour, as the tide gauge was out of service
at the time (see discussion in Chapter 3 and Ingram, 2005).
This event caused extensive damage and was the worst storm to hit the region
since 1974 (Bateman, 2000; Ryan 2000). The peak sustained wind velocity was recorded
at 96 km/h at 1:30 a.m. NST on 22 January, with a maximum gust of 137 km/h. During
this time, a wave-rider buoy recorded waves offshore to be approximately 15 m in height.
Environment Canada meteorologist John Macphee conducted a field assessment of the
Port aux Basques area following the event, and estimated that a rogue surge wave of
about 18 m height hit the community at around 3:00 a.m NST (Macphee, personal
communication; Bateman, 2000; Ryan, 2000).
15
The surge primarily impacted the Channel Head area of the town and caused the
greatest extent of damage. Homes received considerable damage, including flooding and
the removal of siding and roofing shingles. Vehicles were damaged by flying debris and
inundation, and exterior structures were destroyed. The 8 tonne Fisheries & Oceans
Canada mariner fog alarm buoy was shifted more than 1 km into the harbour. Coast
Guard equipment mounted on Channel Head received damage extending to 21 m asl,
suggesting that the wave impacted at ca. 16-18 m elevation, with salt spray extending a
further 3-5 m upward. Severe destruction to the walkways and other equipment at the
Coast Guard installation, however, at about 18 metres above sea level, was directly
caused by the wave (Bateman, 2000; Forbes et al., 2000; Ryan, 2000).
Overall, residential damage for this surge event alone totaled at least $280,000.
Damage to municipal infrastructure, primarily the sewage outfalls, was assessed at over
$400,000 (Bateman, 2000; Municipal and Provincial Affairs, 2000). The total economic
damage figure was estimated at more than $1 million (Len LeRiche, Public Safety and
Emergency Preparedness Canada, personal communication).
The actual monetary costs of disasters are always greater than the quoted values.
Reported figures are commonly are commonly the direct cost of the buildings, property,
and public infrastructure (The H. John Heinz III Centre, 2000; Kumar et al., 2001; Parson
et al., 2003). Discrepancies between insured values, personal expenses covered by
government compensation, and the actual or replacement value of the property lost can be
significant (Kreibich et al, 2004; Hickman, 2006). Monetary values of buildings and
infrastructure are readily determined, using assessed values for taxation or insurance.
Property located outside buildings, such as vehicles, is frequently not covered in total
value by government compensation programs or private insurance. Damage to exterior
property, uninsured items, and indirect costs are not included in the monetary values or
damage estimates quoted, especially those announced within a short time after the event.
The economic impacts of a disaster may continue for years after the event.
Damaged infrastructure may fail earlier than its designed lifespan (Kumar et al., 2001).
Prolonged health care and psychological counseling can be required for victims and
responders (Milne, 2002; Tapsell and Tunstall, 2003).
16
Hickman (2006) conducted an assessment of costs resulting from flood damage in
selected Newfoundland communities, and noted that indirect costs substantially outweigh
those resulting solely from damage to infrastructure. In June 2005, the cost of the
January 2003 flooding at Badger NL was estimated at $8.2 million (Paul Peddle, EMO
NL personal communication). This figure is more than 25 times the original estimate of
potential physical damage estimated by FENCO (1985), corrected for inflation, although
the 2003 flood waters reached almost exactly the elevation assumed in the 1985 study.
Much of the difference is represented by more accurate assessment of indirect costs not
associated with immediate response, rescue, and restoration of structures to pre-flood
conditions.
Hickman (2006) calculated that the March 2003 rain-on-snow flooding event in
Corner Brook, which resulted in $1.4 million in direct (recorded and announced)
damages, actually had an economic impact on the order of $5 million, although no deaths
or serious injuries resulted. Similar recorded damage totals resulted for the Burin
Peninsula from the impact of Hurricane Luis (1995) and for Torbay for Tropical Storm
Gabrielle (2001).
The actual costs of the flooding events studied in Newfoundland were more than
twice the reported figures in all instances. Applying a similar standard to Port aux
Basques would suggest that the actual financial impact of the 21-22 January 2000 storm
surge event would approach $ 3 million. This figure does not account for any losses
resulting in disruption to transportation between Port aux Basques and the remainder of
Newfoundland.
Social and community impacts of disasters are difficult to quantify. They are
commonly not recorded in estimates of ‘total cost’ of flood damage, which tend to be
expressed in monetary terms. Flooding hazards may impact individual perceptions of
personal security, producing stresses that are not directly expressed in monetary terms.
For community residents these impacts are as relevant as quantitative costs, and may be
more lasting.
The potential impact of a storm surge on Port aux Basques was the subject of an
exercise for municipal officials, first responders, emergency measures personnel, and
other responsible individuals on 13 June 2006 (see Seguin et al., 2006).
17
Prior to the January 2000 surge event, the most recent comparable surge occurred
on 20 October 1974. Logged water-level, atmospheric pressure, and wind data were
examined (Ingram, 2005). During this event, peak winds gusts reached the same
maximum as in the 2000 storm (137 km/h) and the maximum sustained winds were 84
km/h. Extensive damage was caused, including the destruction of the helicopter pad at
Channel Head. Sections of railway track along the coast at Osmond and north of Cape
Ray were damaged by waves and surge, which subsequently caused the derailment of two
diesel locomotives as they attempted to negotiate the damaged track (Bateman, 2000).
The lesser storm surge events which occurred in association with Hurricanes
Gustav (2002) and Frances (2004) primarily impacted the sand-dominated beach systems
at Grand Bay and JT Cheeseman Provincial Park, northwest of Port aux Basques. The
times of storm landfall on both occasions did not coincide with astronomical high tide,
reducing the storm surge heights. No damage was noted to installations in Port aux
Basques Harbour, although erosion of the dune-backed coastlines was notable following
Gustav.
The relative timing of storm surge events with respect to astronomical high tide is
critical. Hurricane Gustav did little damage in Charlottetown PEI, primarily because the
storm surge coincided with a lower tidal position, approximately 4 hours before
astronomical high tide. Environment Canada noted that if the storm surge had coincided
with high tide, water levels would have been comparable to those recorded during the
January 2000 event (http://www.atl.ec.gc.ca/weather/hurricane/gustav02_e.html), which
brought widespread flooding. Storm surges induced by hurricane activity thus are
potentially significant at Port aux Basques.
2.3 Tsunamis
Tsunamis are the products of seismic activity, and are not related to climate.
However, their potential impact on the southwest Newfoundland coastline is similar to
that for storm surges.
The 1929 Burin Tsunami killed 28 people in Newfoundland and 1 in Cape Breton,
a greater death toll than for any other Canadian seismic event (Ruffman, 1991, 1993,
1995a; Fine et al., 2005). The impact of the tsunami was felt along the south coast of
18
Newfoundland, from the Burin Peninsula west to Port aux Basques, although all the
Newfoundland deaths and almost all of the destruction occurred along the Placentia Bay
shore of the Burin Peninsula. Runup heights reached 13 m asl (Fine et al., 2005). Some
damage was noted to fishing vessels, stages, and gear in Burgeo, but there were no
injuries. The occurrence of other tsunami events, notably in 1864 at St. Shotts (Avalon
Peninsula) has been suggested (Ruffman 1995a, 1995b), but these have not been verified,
either by historical accounts or through geological studies.
Preliminary investigations at Burgeo have not revealed the distinctive tsunami
laid sands (TLS) that commonly mark landfall areas for tsunamis, both on the Burin
Peninsula (e.g. Ruffman, 1993; McCuaig and Bell, 2005) and elsewhere (e.g. Dawson,
1999). However, TLS deposits are generally preserved in isolated lagoons, salt-water
marshes, and other low-energy environments not influenced by repetitive wave erosion.
The lack of suitable preservation areas at both Burgeo and Port aux Basques Harbour
means that TLS deposits would not be expected to be preserved, even in areas that were
known to have experienced tsunami activity.
The occurrence of the Burin Tsunami demonstrates that tsunami waves, of
comparable elevation to the largest waves associated with storm surges, could strike the
coastline in the Port aux Basques and Burgeo areas. The total damage to property on the
Burin Peninsula was estimated at about $1 million in 1929 dollars (Liverman et al.,
2001), equivalent to ca. $11 million in 2006. This figure, however, must be regarded as
an extremely low estimate. In addition to the difficulties involved in estimating the actual
costs of damage from natural hazards, as alluded to above, the infrastructure destroyed
along the Burin Peninsula in 1929 consisted largely of wooden stages, small fishing
vessels, and houses. A comparable event today would result in much greater monetary
loss.
2.4 Coastal Erosion
The sensitivity of a coastline to erosion is governed by the energy and frequency
of wave action, and by the physiography and geological composition of the coastal zone.
The majority of the southwestern coast of Newfoundland lies within the Newfoundland
Uplands of Appalachia (Bostock, 1970). Eastward from Port-aux-Basques to Burgeo,
19
fjard morphology characterizes the shorelines developed on Palaeozoic granite and
associated igneous rocks (Riley, 1959; Dickson et al., 1996), with irregular embayments,
numerous skerries and small islands. Embayments are variable in depth, with irregular
profiles influenced by differential pre-glacial weathering and glacial scouring. This area
is generally resistant to coastal erosion, except where accumulations of sand backed by
coastal dunes are present, as at Sandbanks Provincial Park (Catto 2002, 2006a; Ingram
2004). Burgeo Harbour, flanked by exposed granite, is not subject to coastal erosion,
even during storm surges.
Metamorphosed Palaeozoic units (Port-aux-Basques schist, van Staal et al., 1996)
underlie the coastline extending northwestward from Port-aux-Basques to J.T.
Cheeseman Provincial Park and Cape Ray Cove. The structural weaknesses and
lithologic divisions in the metamorphic units generally trend NE-SW. Erosion, both by
coastal and terrestrial processes, has exploited the planes of weakness, creating a
shoreline marked by shallow coves separated by rock spurs aligned parallel to the
geological structure. This alignment mirrors that of the prevailing winds of the area,
resulting in topographic funneling of waves into embayments.
In areas where bedrock is exposed, such as Port aux Basques Harbour, weathering
is confined to terrestrial processes, primarily frost action. The coastline is not subject to
erosion by waves, even those resulting from hurricanes and storm surges.
Erosion has affected the dune-backed coastlines of Grand Bay West and JT
Cheeseman Provincial Park, northwest of Port aux Basques, and Sandbanks Provincial
Park, near Burgeo. Along the Gulf of St. Lawrence coast of Newfoundland, the
combination of rising sea level, increased human utilization of the coast for tourism
purposes, and limited offshore winter ice conditions have resulted in accelerated erosion
and degradation of the dunes and coastline (Pittman and Catto, 2001; Catto, 2002a,
2006b; Ingram 2004). Ingram (2004) noted erosion at the rate of 0.7 m per month
between December 2003 and April 2004 at Sandbanks Provincial Park, concentrated in
the late summer-autumn period, and in early winter before freezing of the beaches
occurred, providing some measure of protection. This rate of erosion represents a
substantial acceleration from previous estimates (Catto, 1994).
20
Figure 2.1: Coastal Erosion at Sandbanks Provincial Park, Burgeo. View looking to the northwest at the mid-section of the beach, 9 April 2004 (Dan Ingram)
Figure 2.2 Sand-dominated beach and backing dune, JT Cheeseman Provincial Park, showing mobilization of coarse clasts, evidence of recent storm-surge erosion.
21
The impacts of climate change and variation, storm events, and human activity on
J.T. Cheeseman and Sandbanks Provincial Parks, and the impact on Piping Plover
(Charadrius melodus) have been discussed in detail elsewhere (Catto, 2002a, 2002b). A
summary of the principal findings of these previous investigations is presented here.
In southwestern Newfoundland, coastal dune development and associated sandy
beach evolution is related to destabilization of littoral areas initiated by marine
transgression (Catto, 1994; Catto, 2002a). Consequently, rising sea level, ca. 3.3 mm/a,
is acting to destabilize the coast, increasing vulnerability to coastal erosion and storm
surges. The beaches of southwestern Newfoundland are subject to reworking and
modification throughout most or all of the year. The coastline typically remains entirely
ice-free until February, and during some years, it may remain ice-free throughout the
winter.
Removal of overlying fine sand has exposed underlying hard-packed medium
grained sand, and storm-transported shell hash, coarse sand, granules, and fine pebbles
now overlie many areas. Storm-driven waves have resulted in bank erosion in some
areas of the dune complex at JT Cheeseman in excess of 1 m between summer 1999 and
June 2002 (Catto, 2002a, 2002b). In addition to changes in grain size distribution
resulting from fluctuating longshore drift, storms, snow cover, aeolian activity, and
humans also cause changes in the sediments exposed on the beach.
Regional changes in temperature and precipitation are only secondarily
responsible for dune modification and erosion. Boreal conditions prevailed from mid- to
latest Holocene in southwestern Newfoundland (see Davis et al., 1987; Davis, 1993;
Anderson and Macpherson, 1994; Macpherson, 1995). The sedimentary structures within
the dune sequences throughout southwestern Newfoundland indicate that formative
processes remained similar throughout the period of dune accumulation. In the absence of
detailed chronological investigations, there is no evidence to suggest any substantive or
consistent change in formative processes over time. Local climate conditions governing
sediment flux, and human disturbance of the dunes, are more significant than are broad
changes in regional climate.
22
The available information for southwestern Newfoundland suggests that any
summer warming trend may be offset by increasing summer precipitation, and the overall
perhumid moisture regime is not expected to vary significantly under current climate
change scenarios (Lewis, 1997; Lines et al., 2003). Future conditions would not be
optimal for sand dune formation or expansion. Limited sand remobilisation from dunes
to coast over a long period will lead to gradual coarsening of the beaches. If beaches are
deprived of sand from longshore transport, there is no ready source of sand from
stabilized dune fields, and consequently the coarsening process will be accelerated under
storm wave reworking. As dunes and beaches are linked parts of a system, a reduction in
dune mobility results in a decrease of sand availability for beach maintenance. This
could have an impact on tourist utilization and perception of the beach systems (Catto,
2004).
The high winds associated with storms are accompanied by precipitation, which
simultaneously diminishes their effectiveness in eroding the higher dunes. Storm winds
are most effective at eroding previously existing trough and linear blowouts, and are
relatively ineffectual at eroding windward surfaces. In undisturbed areas, the strongest
storm winds tend to sweep across the dune surface, and may result in accretion where
small saucer blowouts are infilled by grainfall deposits upon quiescence.
The primary effect of storm activity on the dunes is to destabilize the dune
surfaces, rendering them vulnerable to anthropogenic disturbance. By removing
vegetation and sweeping debris from linear blowout bases, the storm winds create freshly
exposed surfaces that are subsequently available for human reworking. The propagation
of linear blowouts is facilitated by the strong storm winds, thus widening and deepening
the tracks and making them more attractive for human foot traffic. The storm winds also
rework and deepen deflation hollows. Deflation hollows influenced by anthropogenic
bonfires and quarrying are particularly susceptible to deepening and widening during
storms.
Natural impacts are related primarily to storm winds, waves, and surges. The
decrease in sediment influx from the dunes also plays a role, and the slowly rising sea
level has a lesser influence. These processes have resulted in erosion, coarsening of
23
sediment along the shoreface, and a gradual steepening of the beach profile. The natural
effects are currently muted by the generally low energy of the beach environment, and
the presence of sufficient time between storms in most years, with the exceptions of
1995, summer 1999-January 2000, and the period autumn 2004-autumn 2005, including
Hurricane Frances.
2.5 Sensitivity to Sea Level Rise
Assessment of the sensitivity of a shoreline to erosion resulting from sea level rise
involves consideration of several variables. Study of shorelines in the eastern United
States by Gornitz (1993), Gornitz et al. (1991, 1993), and of Canada by Shaw et al.
(1998) led to the identification of parameters which can be used to assess the sensitivity
of a shoreline to erosion. Shaw et al. (1998) list seven critical parameters:
• relief,
• rock and/or sediment type exposed along the shore,
• landform type (e.g. cliff, beach, salt marsh),
• tendency of sea-level change (amount of rise or fall per 100 years),
• shoreline displacement (laterally, expressed in m / a);
• tidal range, and
• mean annual maximum significant wave height
Shaw et al. (1998) assigned each parameter an equal weight, and ranked variations within
each from 1 (very low sensitivity) to 5 (very high sensitivity). By combining the scores
for each parameter, sensitivity indices (SI) can be calculated as:
SI = √ (product of scores of all 7 parameters / 7)
Thus, a shore with the least sensitivity to coastal erosion would have a SI of √ (1/7), or ~
0.38, whereas the greatest value possible is √ (5 x 5 x 5 x 5 x 5 x 5 x 5 / 7), or ~108.
24
Shaw et al. (1998) divided the coastline of Canada into three categories of SI.
Coastlines with low sensitivity had SI values of ≤ 4.9; moderately sensitive coastlines had
values between 5.0 and 14.9; and highly sensitive coastlines had values in excess of 15.0.
A single sensitivity index was calculated for all 2899 of the 1:50,000 map areas along the
Canadian coastline.
Throughout the analysis, Shaw et al. (1998) carefully indicate that the regional
nature of this investigation may serve to partially conceal local problem areas.
Investigation on a regional scale (c.f. Catto et al., 2003; Daigle et al., 2006) allows
further subdivision of parameters, assessment of their relative importance locally, and
designation of more specific areas for categorization.
Shorelines with high relief above sea level are relatively insensitive to erosion. In
contrast, shorelines with relief less than the mean significant wave height are susceptible
to periodic inundation, increasing the potential for erosion. Offshore of eastern
Newfoundland, the mean annual significant wave height is estimated at 7 m - 8 m (Neu
1982; see also Lewis and Moran, 1984), with the 10-year and 100-year values estimated
at 11 m and 15 m respectively. These values can be compared with the recorded 15 m
height at the offshore wave-rider buoy and 18 m inundation level associated with the
January 2000 event. Estimates of significant wave heights based on modeling tend to
underpredict extreme storm wave heights (Bacon and Carter, 1991; Cardone and Swail,
1995; Cardone et al., 1995), and wave heights in excess of 30 m have been recorded
offshore of the south coast of Newfoundland during storm events (Swail, 1997).
In this study, shorelines with relief less than 7 m are considered to have a very
high risk relief factor (5). Shorelines with relief less than 15 m are considered to have a
high risk relief factor (4), and those with relief less than 20 m are assessed as moderate
(3). Areas with relief of 30 m or less are assessed as having low risk (2), and those above
30 m are at very low or negligible risk (1).
The primary difference related to rock and sediment type along the coastline
distinguishes areas with relatively resistant bedrock (such as Port aux Basques Harbour)
from areas of coastal sand dunes (such as Grand Bay West and JT Cheeseman Provincial
Park). The resistant granite of the Burgeo area has a very low risk factor (1). The schist
surrounding Port aux Basques Harbour is less resistant to frost wedging, due to its
25
jointing and fracture pattern, but its sheltered position with respect to most storm tracks
limits its exposure, reducing the sensitivity (2). In contrast, areas with exposed aeolian
sand dunes flanking sandy beaches, open to the direction of prevailing winds, are very
sensitive to erosion (with a sensitivity factor of 5).
Landform type also influences the sensitivity to coastal erosion. The steep fjard
coastlines between Burgeo and Port aux Basques (1) and the rock platforms surrounding
Port aux Basques Harbour (2) are less sensitive to erosion than are the dune-backed
coastlines (4).
The tendency of sea-level change (amount of rise or fall per 100 years) also
controls coastal erosion. The rankings of sensitivity indices for these factors follow those
of Shaw et al. (1998). For Port aux Basques, sea level is currently rising at 3.3 mm/a, ca.
33 cm per 100 years. Coastlines with sea level rising between 21 and 40 cm/100a are
assigned a sensitivity factor of 4 by Shaw et al. (1998).
Sensitivity factors for shoreline displacement vary from very low (1) for accreting
shorelines, through low (2) for shorelines showing no net displacement, to very high (5)
for shorelines receding at rates in excess of 1 m/a. Values throughout the study region
for this parameter thus range from very high at Sandbanks Provincial Park (rates >> 1
m/a, Ingram 2004) to very low. At Port aux Basques Harbour, the bedrock shoreline has
shown no perceptible change, and small gravel fringes have accumulated in some
locations. The harbour is assigned a sensitivity factor of very low (1) for this parameter.
Tidal ranges in eastern Newfoundland lie within the microtidal and very lowest
mesotidal limits. Port-aux-Basques Harbour has a mixed, mainly semi-diurnal tidal
regime. The range during mean tide is 1.1 m, rising to 1.6 m during spring tide
(Canadian Hydrographic Service, 2004 and 2005). Similar microtidal regimes were
assigned a sensitivity factor of low (2) by Shaw et al. (1998).
The mean annual maximum significant wave height is also important in
assessment of the sensitivity index. Along the eastern Newfoundland coastline, the
significant wave height of 7 m - 8 m (Neu, 1982) establishes this parameter as having a
very high sensitivity ranking.
26
By combining the values for all seven sensitivity factors, an overall coastal
sensitivity index can be calculated. For Port aux Basques Harbour, the Coastal
Sensitivity Index is:
CSI = √ (3 x 2 x 2 x 4 x 1 x 2 x 5) /7 = 8.3
This value lies in the lower range of the ‘moderate’ sensitivity classification. For Port
aux Basques, the sensitivity factors relating to sea level history and wave activity are far
higher than the geological and topographical factors. As all factors are equally weighted
in the formula, the overall result suggests low-moderate sensitivity. Observations of the
ineffectiveness of storm surges and waves on erosion of this coastline, however, suggest
that the geological factors are locally dominant. Overall, Port aux Basques Harbour is
not sensitive to coastal erosion.
For Sandbanks Provincial Park, the Coastal Sensitivity Index is:
CSI = √ (5 x 5 x 4 x 4 x 5 x 2 x 5) / 7 = 53.5
This value indicates a coastline highly sensitive to erosion, which is in agreement with
observations at the park.
27
2.7 Summary
• Sea level is currently rising at Port aux Basques at ca. 3.3 mm/a.
• Rising sea level will allow successive storm surges to rise higher and penetrate
further inland.
• The coastline of southwestern Newfoundland has been subject to at least 5 storm
surge events since January 2000. The largest of these was the storm surge of 21-
22 January 2000.
• The estimated economic damage from the January 2000 event exceeded $1
million. However, study of other flooding events in Newfoundland indicates that
actual costs were more than twice the reported figures in all instances. Applying
a similar standard to Port aux Basques would suggest that the actual financial
impact of the 21-22 January 2000 storm surge event would approach $ 3 million.
This figure does not account for any losses resulting in disruption to
transportation between Port aux Basques and the remainder of Newfoundland.
• The shoreline at Port aux Basques Harbour is not sensitive to coastal erosion
resulting from sea level rise. Coastal erosion is occurring along dune-backed
sandy shorelines, such as those at JT Cheeseman and Sandbanks Provincial Parks.
28
3. Analysis of Tidal and Storm Surge record at Port aux Basques Harbour
Dan Ingram, Brad DeYoung, Norm Catto, Evan Edinger
3.1 Introduction and Methodology
Port aux Basques is prone to frequent storm activity, particularly intense winds.
Storm surges are commonly a consequence of such events. This chapter summarizes the
investigations of the long term impacts on water level height, assessing the role of tidal
variation on storm surge elevation. Detailed discussion is presented by Ingram and
DeYoung (2005) and Ingram (2005). The aims of this investigation were:
• to determine whether the tidal regime is changing over time;
• to determine the astronomical variations effecting any changes;
• to relate any residual change in tidal regime to changes in sea level and/or wind or
storm surge activity; and
• to assess the implications, particularly with respect to the impact on port and ferry
operations.
Statistical analysis utilized tide and climate data obtained from the Marine
Environmental Data Service (MEDS) of Fisheries and Oceans Canada, and Environment
Canada, respectively. The tide data dates back to 1935 but contains many large gaps,
particularly during the 1930s through to the 1950s. The set, however, is largely complete
from 1959 to present, although gaps exist due to mechanical problems with the gauge.
For the purposes of this study, records from the 1950s through to the end of April 2005
were analysed. Unfortunately, there is no climate data for the Port aux Basques station
prior to 1966.
The tide and pressure data was analysed using MATLAB (Version 6.5.1.199709
Release 13) in conjunction with T_TIDE. These programs were accessed through a
computer work station in the Department of Physics and Physical Oceanography at
Memorial University. T _TIDE was obtained from Professor Rich Pawlowicz, Ocean
Dynamics Laboratory, University of British Columbia (http://www2.ocgy.ubc.ca/~rich/).
29
3.2 Analysis
Initially, data was reconfigured for compatibility with MATLAB and T_TIDE.
This included converting the dates to the Julian calendar and the times from
Newfoundland Standard Time (NST) to Greenwich Mean Time (GMT). The data was
placed in annual increments for analysis using T_TIDE. Classical tidal harmonic analysis
(Godin, 1972) was completed on the raw, unaltered water level data. This separated the
predicted harmonic tide from the actual recorded water level, and thus separated the tidal
residual from the actual tide.
The dominant tidal constituents were identified from the predicted harmonic tide.
The frequency, amplitude, and phase of each constituent were separated and listed in an
ASCII file. Generally, 67 constituents were identified for each data set but the number
varied depending on the completeness of the record for any particular year.
For this study, only the most significant constituents (those with an amplitude
exceeding 0.0400 m) were investigated further. Eight such constituents were identified;
S2, M2, N2, K1, O1, K2, SSA, and SA. The frequencies of each are listed below in Table
3.1.
30
Table 3.1: Tidal harmonic description, period, and frequency of selected tidal
constituents (modified from LeBlond and Mysak, 1978).
Constituent
Tidal
Harmonic
Description
Period
(semi-diurnal,
diurnal, or longer)
Period
(mean solar
hours)
Frequency
(cycles per hour)
S2 Principal solar Semi-diurnal 12.00 0.0833333
M2 Principal lunar Semi-diurnal 12.42 0.0805114
N2 Longer lunar
elliptic
Semi-diurnal 12.66 0.0789992
K2 Luni-solar
declinational
Semi-diurnal 11.97 0.0835615
K1 Soli-lunar
declinational
Diurnal 23.93 0.0417807
O1 Main lunar Diurnal 25.82 0.0387307
SSA Solar semi-annual Longer period 4393.3
(182.6 days)
0.0002282
SA Solar annual Longer period 8767.6
(365.2 days)
0.0001141
An annual mean time series was plotted for the amplitude of each constituent. The
most evident trends or cycles were shown by K1, N2, M2, O1, and S2.
Once the predicted harmonic tide and its constituents were identified and removed
the raw residual water level data was analysed. It is this component that is of greatest
interest since it includes the atmospheric pressure component, amongst other factors, and
any associated storm surge events.
3.2.1 Residual Water Level
The residual, non-tidal data was zeroed by subtracting the mean from each data
point. Each annual time series was then prepared for filtering in T_TIDE, to remove any
non-tidal noise from the data. For filtering, each series had to be relatively complete,
31
generally with record gaps not exceeding one month. Years with large continuous gaps,
or numerous smaller ones, were omitted for the purposes of filtering and further analysis.
Filtering in MATLAB requires that any time series must be complete with no gaps, and
therefore, any gaps in the record had to be infilled with data that was interpolated. This
could be reasonably done with gaps less than one month in duration, but not with large or
frequent ones. For the purposes of this analysis, simple linear interpolation was used.
This did not fill the gaps with accurate water level data but rather simply filled the voids
allowing a filter to pass over without complications, as filters do not respond well to
discontinuity.
The Butterworth digital lowpass IIR filter (Etter, 1993) was used for each annual
time series. Butterworth filters have maximally flat passbands and stopbands and are
written as:
[B,A] = butter(N,Wn)
with N representing the order of the filter and Wn being the cutoff frequency normalized
to the Nyquist frequency (Etter, 1993). For the filtering of the water level residual, an
order of 6 (N) and a cutoff frequency of 0.03 cph, or roughly 33 hours, were used.
Although the filtered data removes other noise (such as instrumental error and
high frequency variability), permitting a more accurate statistical assessment of trends,
the raw water level residual is still utilised, particularly when dealing with storm and
surge events since the main interest is with the actual water level is those situations.
Therefore, the annual raw residual time series were used to determine annual maximum
events and the length of time that water levels exceeded particular thresholds.
3.2.2 Extreme Water Level Events
Two water level thresholds were used. The most important threshold is a
residual, or surge, that exceeds 60 cm. This is the widely recognised definition of a storm
surge event (c.f. Murty, 1984; Forbes et al., 2004). Figure 3.1 shows the number of
events that exceeded 60 cm each year and the number of hours exceeding this level.
The same data was also plotted using a threshold of 40 cm (Figure 3.2). This
provides an indication of the trend of water level events greater than the mean. Although
32
there may be no evident trend for actual surge events (those exceeding 60 cm), there may
be a large increase in higher water level events. Evident increases in high water levels
may not be sufficiently extreme enough to be classified as surges. Utilising a lower
arbitrary water level threshold in conjunction with the standard storm surge definition
allows better assessment.
Years with a complete data set are identified by the solid blue bars, and those
years with partial records are represented by the grey bars. Any years with significant
gaps, particularly during the winter months, have been omitted and marked with an
asterisk. A data set was considered complete (solid blue) if no gaps exceeding 24 hours
were present in the record, meaning that the yearly data set must be at least 97.3%
complete. The plots were excluded totally (marked by an asterisk) if the winter record
was missing more than 30 days in total, or if the annual data set was missing more than a
total of 90 days. Thus, the winter data set had to be more than 66.7% complete, and the
overall yearly record had to be more than 75.3% complete. All other years were
classified as having partial records (grey shading).
33
1960 1965 1970 1975 1980 1985 1990 1995 2000 20050
1
2
3
4
5
6
7
Year
Num
ber
of
Events
1960 1965 1970 1975 1980 1985 1990 1995 2000 20050
5
10
15
20
25
Year
Dura
tion o
f E
vents
(H
ours
)
(A)
(B)
* * * * * * * * * *
* * * * * * * * * *
34
Figure 3.1: The number of storm surge events (water level exceeding 60 cm) (A) and the number of hours the water level exceeds 60 cm (B) by year in Port-aux-Basques (1959 – 2004). The blue bars indicate a complete data set (less than 1 day total gap). Grey bars indicate partial data sets (a total gap exceeding 1 day but less than 90 days annually and/or 30 days during the winter). Asterisks (*) indicate omitted data sets due to very large gaps (more than 90 days total and/or more than 30 days during the winter).
35
1960 1965 1970 1975 1980 1985 1990 1995 2000 20050
5
10
15
20
25
Year
Num
ber
of
Events
1960 1965 1970 1975 1980 1985 1990 1995 2000 20050
20
40
60
80
100
120
Year
Dura
tion o
f E
vents
(H
ours
)(A)
(B)
* * * * * * * * * *
* * * * * * * * * *
36
Figure 3.2: The number of water level events exceeding 40 cm (A) and the number of hours that the water level exceeds 40 cm (B) by year in Port-aux-Basques (1959 – 2004). The blue bars indicate a complete data set (less than 1 day total gap). Grey bars indicate partial data sets (a total gap exceeding 1 day but less than 90 days annually and/or 30 days during the winter). Asterisks (*) indicate omitted data sets due to very large gaps (more than 90 days total and/or more than a 30 days during the winter).
37
3.2.3 Climate Factors
Atmospheric pressure data was converted to a water height equivalent (in metres)
for comparison with water level data. This allows an assessment as to how much, if any,
of the water level fluctuation is pressure dependent.
Wind speeds were converted to m/s and was used to calculate the drag coefficient
(CD) using the methods of Large and Pond (1981). The drag coefficient was reduced to
10 m height and neutral atmospheric conditions (CDN) (Large and Pond, 1981).
Once the CDN was defined, the zonal (u) and meridional (v) components of wind
speed and the wind stress was resolved into its zonal (τx) and meridional (τy) components:
τx = ρA·CDN·u(u2 + v2)1/2
τy = ρA·CDN·v(u2 + v2)1/2,
where ρA is the density of air (approximately 1.26 kg/m3).
Using the zonal and meridional components, the absolute mean wind stress (τ)
values could be calculated (in N·m-2 or Pa) as:
|τ| = (τx2 + τy
2)1/2.
As an absolute value the wind stress was plotted as a time series for composition
with the residual water level and atmospheric pressure data plots. For this study, only the
absolute values were considered. If specific storm events and associated impacts were to
be studied, it would be valuable to consider each directional component separately. This
would be particularly true when investigating the relationship between any given wind
direction and the recorded water level in Port aux Basques Harbour.
3.3 Interpretation
3.3.1 Tidal Cycles
The most obvious cyclic patterns are seen with the amplitudes of M2, O1, and K1,
all of which display two clear oscillations with a period of about 18 years each (figure
3.3, 3.4. 3.5). These are thus likely the dominant components of the 18.6-year tidal cycle.
A longer time series, however, would be required to make any definite interpretations.
38
1930 1940 1950 1960 1970 1980 1990 2000 20100.41
0.415
0.42
0.425
0.43
0.435
0.44
0.445
0.45
0.455
0.46
YEAR
Am
plit
ude (
m)
Figure 3.3: Amplitude for tidal constituent M2 (1935 - 2005) based on analysis of hourly data from each year.
39
1930 1940 1950 1960 1970 1980 1990 2000 20100.07
0.075
0.08
0.085
0.09
0.095
0.1
0.105
0.11
0.115
YEAR
Am
plit
ude (
m)
1930 1940 1950 1960 1970 1980 1990 2000 20100.065
0.07
0.075
0.08
0.085
0.09
0.095
YEAR
Am
plit
ude (
m)
Figure 3.4: Amplitude for tidal constituent O1 (1935 - 2005) based on analysis of hourly data from each year.
Figure 3.5: Amplitude for tidal constituent K1 (1935 - 2005) based on analysis of hourly data from each year.
40
For each constituent, the 18-year cycle can be attributed to the previously
identified tidal cycle, although the 2 separate 18-year oscillation sets are of different
variance. A longer time series that illustrates more of the cycles would be required to
make any interpretations. The same can be said for downward trend, as it cannot be
accurately explained without a longer time series.
3.3.2 North Atlantic Oscillation
The cyclic pattern of the constituents, particularly M2 that has the dominant
influence due to its relatively large amplitude, was also compared to the North Atlantic
Oscillation (NAO; Hurrell et al., 2003).
The M2 and NAO display a similar cyclic pattern with similar periods (Figure
3.6). The time series are also plotted along with the annual maximum surge. The annual
maximum surge bar plot has been colour coded on the basis of completeness of the
record. Years with no significant record (1964 and 1979) have been omitted completely.
To evaluate the relationship between M2 and the hours of exceedence of a 40 cm water
level and the NAO, scatter plots were constructed (Figure 3.7). From these plots it is
clear that there is no real correlation, although all three variables exhibit some cyclical
pattern.
41
1960 1965 1970 1975 1980 1985 1990 1995 2000 20050.41
0.42
0.43
0.44
0.45
0.46
0.47
M2 Amplitude
Wate
r Level (m
)
Year
1960 1965 1970 1975 1980 1985 1990 1995 2000 20050
0.2
0.4
0.6
0.8
1.0
Annual Maximum Surge
Year
Wate
r Level (m
)
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005-6
-4
-2
0
2
4
6
NAO Index
Year
(A)
(B)
(C)
42
Figure 3.6: Yearly comparison of the amplitude of tidal constituent M2 (A), the NAO Index (B), and annual maximum surge height (de-tided residual) (C). Complete data sets and those with gaps are shown in blue and grey, respectively.
43
-6 -4 -2 0 2 4 60.4
0.5
0.6
0.7
0.8
0.9
1.0A
nnual M
axim
um
Surg
e (
m)
NAO Index
-6 -4 -2 0 2 4 60
20
40
60
80
100
120
140
NAO Index
Dura
tion (
Hours
)(A)
(B)
44
Figure 3.7: Scatter plots of the NAO Index versus the annual maximum surge height (A) and the number of hours per year that the water level exceeds 40 cm (B) (1959 – 2004). Note the lack of correlation between the two variables in each plot.
45
Scatter plots were also constructed comparing the NAO Index versus the number
of events exceeding 40 cm and 60 cm and the number of hours that the water level
exceeded 60 cm. No relationship was evident in either plot. Similarly, no relationship
was present when the NAO was plotted against the annual maximum surge either. These
results complement the work of Karn (2004) who indicated that the local significance of
the NAO is very variable and no clear relationship or trend exists with respect to wind
speed in Atlantic Canada.
3.3.3 Residual Water Level
The residual water level displays a very clear seasonal trend, as is evident when
the monthly mean residual water level is plotted (Figure 3.8). The fall and winter months
have a higher mean water level and a higher variance than do the spring and summer.
This is expected as the stormiest months are during the fall and winter, which would
cause increased surge activity and generally higher water levels. Based on mean seasonal
data (1959-2005), the ratio of the standard deviations of the mean winter (January,
February, March) and summer (July, August, September) water level is approximately
1.6, a considerable difference.
46
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
Month
Wate
r Level (m
)
Figure 3.8 Monthly mean water level (de-tided residual) and variance from 1959 – 2005
There is a clear seasonality shown by the data, with higher water levels in the fall
and winter months (Figure 3.8). Therefore, the plot displaying the mean annual water
level (Figure 3.9) should be used primarily to further emphasize the large variability in
the water level, as well as the challenges of working with an incomplete, very fragmented
data set.
47
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
Month
Atm
ospheric P
ressure
(H
eig
ht equiv
ale
nt in
metres)
Figure 3.9: Monthly mean atmospheric pressure (height equivalent in metres) and variance from 1959 – 2005.
3.3.4 Influence of Atmospheric Pressure and Wind on Water Level
Residual water level is greatly influenced by atmospheric pressure and local wind,
amongst other less significant factors. For Port aux Basques, its location with respect to
northerly and north-easterly tracking low pressure systems and their associated winds
provide many examples of this interaction.
Every storm and associated surge is unique. There is no one template or set of
guidelines outlining how a particular system will impact any given area. There is,
however, some strong relationships that exist between water levels and atmospheric
pressure and wind (Table 3.2). Atmospheric pressure, similarly to water level, shows
48
obvious seasonality. The mean monthly pressure, plotted as height equivalent, is
basically the inverse of the water data for the same period (1959-2005).
Table 3.2. Recorded and calculated data for selected storm events.
Recorded / Calculated Variable JAN 2000 OCT 1974 FEB 1969
Maximum actual (m) nd 2.15 2.54
Maximum residual (m) nd 0.51335 0.82421 Water Level
High tide prediction (m) 0.53636 0.49543 0.49543
Atmospheric Minimum recorded value (kPa) 96.98 97.73 98.24
Pressure Minimum height equivalent (m) -0.41787 -0.34918 -0.3044
Proportion of surge due to pressure (%) nd 68% 40%
Maximum speed (km/h) 96 84 93
Direction (deg) 180 170 110
Direction (descriptor) S S E Wind
Max stress (Pa) 1.9842 0.87116 1.1858
Seasonal sea-level rise is illustrated in the monthly mean water level, or is at least
an active factor, amongst others such as wind stress. The opposite is true during the
summer months. The variance is much less and the mean is much smaller. The obvious
seasonal difference in variance, for both the water level and atmospheric pressure, is
likely due primarily to the climatic regime. Port aux Basques is prone to fall and winter
storms and such isolated events will create anomalies in the data and thus increases the
variance. Conversely, the summer months are relatively calm and the isolated storms are
typically less severe resulting in less variability in the data.
The influence of atmospheric pressure is evident for specific storm events as well.
A relationship clearly exists as the water level and wind peak at relatively the same time
as the pressure dips to a minimum. This example displays a somewhat idealistic
representation of the relationship. Other factors, such as wind direction and lag times
attributed to low pressure system movement, are also involved. In this example, the
maximum surge of 0.824 m peaked at approximately 1530 hrs GMT on 4 February. This
practically coincided with the high tide, producing a combined water level of 2.54 m
above chart datum. This is the ‘worse case scenario’ with respect to destructive impacts
for storm surges. If the maximum surge occurred during low tide the actual water level
would be much less since the water level resulting from the harmonic tide would not be
49
factored in. When a high tide and surge coincide there is essentially a stacking effect and
the already elevated water level, as a result of the high tide, is further elevated due to the
surge. The impact is enhanced even further in the event that the high tide is the higher of
the two of the daily cycle and/or it occurs during spring tide conditions.
High winds were prevalent for about 24 hours during the 4 February storm, both
preceding and following the maximum surge. The peak sustained winds (93 km/h) were
logged at 0530 hrs GMT and exhibited a stress of about 1.19 Pa. These winds subsided
for some time later that day but returned again to reach a maximum of 89 km/h (a wind
stress of 0.93 Pa) at 1230 hrs GMT. Thus, the maximum surge lagged the peak winds by
about 3 hours. At this time the stress was gauged to be about 0.93 Pa. Peak winds,
however, primarily serve as a gauge of maximum intensity and the duration of significant
50
30 31 32 33 34 35 36 37 38 39-1
-0.5
0
0.5
1
Wate
r Level (m
)
Year Day
30 31 32 33 34 35 36 37 38 39-1
-0.5
0
0.5
1
Pre
ssure
Heig
ht
(m)
Year Day
30 31 32 33 34 35 36 37 38 390
0.5
1
1.5
2
Year Day
Win
d S
tress (
Pa)
0.824 m
98.24 kPa-0.304 m
89 km/h0.93 Pa
93 km/h1.19 Pa
(A)
(B)
(C)
51
Figure 3.10: Time-series plot of residual water level (A), atmospheric pressure (height equivalent) (B), and wind stress (C): 31 January – 9 February 1969. winds must be noted as well. Often the winds have weakened by the time of the surge
maximum but the sea state still demonstrates the effects of the previously intense winds.
As a result, it cannot be assumed that wind stress does not have a significant impact
simply due to a decrease in velocity at the time of the surge. Similarly to the impact of
atmospheric pressure, the effects on the water level often lag in time. The ocean does not
react instantaneously to changes in environmental or meteorological influences. It takes
time to adjust and thus water level values commonly, but not always, lag wind and
pressure changes.
3.3.5 Extreme Water Level Events
Extreme water level events are relatively common in Port aux Basques. During
the partially complete water level record, there were a total of 69 surge events (residual
water level greater than 60 cm) that persisted for approximately 230 hours over the 45
year period (1959 – 2004), an average of 1.5 events and 5.2 hours of surge conditions
annually. This estimate is less than the actual number, as many events were not logged
due to the very fragmented record. However, the extreme water level record for Port-
aux-Basques displays an oscillating pattern. Some years with a complete data record
indicate no extreme events, while others with only a limited number of water level
records show a large number.
3.4 Recommendations and Suggestions for Future Work
The methods and techniques used for this research were very applicable and
proved to be effective, but the data set was a limiting factor. With a relatively short and
fragmented data set, long term trends could often not be identified. This was particularly
true for changes with respect to storm surge frequency; either exceeding the 40 cm or 60
cm threshold, and maximum storm surge height. It was clear, however, that storm surges
are very variable over the duration of the data.
To make a better assessment of the long term trends, a long time series would
have to be analysed. Unfortunately, the tide gauge in Port-aux-Basques was not installed
52
until 1935 and the record is largely incomplete until 1959 and contains large gaps for the
duration of the record. Therefore, this project can possibly serve as the starting point, or
base-line, for continuing research as more data is collected at Port-aux-Basques. Ideally,
the time-series would be expanded at the end of each year. This, however, will mean that
an obvious trend cannot be established for many more years. The outcome is unknown,
especially as there are predictions that climate change is accelerating and its impacts will
likely be more apparent.
Another option would be to reconstruct the past record. This would involve
significantly more statistical analysis, but is possible. Any such re-construction would be
based on tide gauge records from other Atlantic Canada locations that were operational at
the time. The recent water level data from Port-aux-Basques would first be compared to
the data from other stations. Once a correlation is established the past gaps in the record
would be able to be roughly interpolated. If the other gauge records pre-date 1935, the
records preceding the first Port-aux-Basques data could be interpolated as well. Such
interpolations would not be perfectly accurate for event- or storm-specific water levels,
but could be used to determine the frequency and approximate magnitude of surges.
Thus, it will enable the input of more data to better establish a trend. Actual water levels
could not be determined due to the large local-variability in Atlantic Canada. The same
storm system often has a very different impact in different locations, even if they are
geographically close.
Future research could also be enhanced by upgrading the tidal network. The
gauges should be maintained in a manner that large gaps are not present and any gaps are
not as frequent in the record. This is especially true for the winter months when storms
are more prevalent and having a record of the water level is more critical. Essentially, the
present state of the Atlantic Canadian tide gauge network is not acceptable for scientific
research nor for public safety. This can be exemplified very clearly during the very
intense and destructive storm of January 2000. During this severe storm the gauge was
not operational, had not been for 130 days prior to the surge (since 14 September 1999)
and did not log data for another 38 days after. The total non-operational period for this
gap was 168 days, and many other gaps in the record exceed this. Notably, at least 3
other intense storms (wind stress > 1.5 Pa) impacted the area during this period, and these
53
water levels were not logged. The networks require adequate maintenance and associated
funding, in order for significant and productive research to continue and for public safety.
3.4 Summary
• There is no clear net change in tidal regime for the period of tidal records for Port
aux Basques (1935-present). There is, however, an indication of the de-tided
residual increasing over time (approximately 10 cm over the 46-year record; 1959
to 2005). Unfortunately, this increase cannot be accurately interpreted since the
data set is highly fragmented, but some of the increasing trend is likely due to
relative sea level rise in the area.
• There is a clear seasonal trend in mean water level. The mean and variance is
higher during the fall and winter than in the spring and summer.
• The atmospheric pressure exhibits a clear seasonal trend. The pressure is lower
with a higher variability during the late fall and winter.
• There is no obvious correlation between the NAO and the tidal constituents, such
as M2, or storm surge activity (neither by frequency in terms of number of events
or duration nor by maximum surge height).
• The annual number of events that exceed 60 cm shows no real trend and there has
been little change in the annual maximum storm surge elevation.
• The maximum water level for extreme events, such as the January 2000 storm,
that have been excluded from the data record can be roughly estimated using
basic statistical correlations based on the recorded meteorological conditions
along with the records of other previous storm/surge events.
• Tidal gauge networks require adequate maintenance and associated funding, in
order for significant and productive research to continue and for public safety.
54
4. Records and Physical Impact of Wreckhouse Events
Norm Catto, Jennifer Straatman, Dale Foote, Dermot Kearney
4.1 Previous Research
Wreckhouse Events have impacted surface transportation through southern
Newfoundland since the construction of the Newfoundland Railway, and numerous
anecdotes exist (Morris, 1977; Harding, 1992; Lingard, 1997). Studies and archival
documentation concerning these events, however, are surprisingly limited. Four previous
studies have considered the impacts on transportation and hydroelectric transmission in
the area.
Sutherland et al. (1963) investigated extreme wind events and train delays in the
Wreckhouse-St. Andrews area for the period 1956-1962, at the request of Canadian
National Railways. The wind data used in the study was from the weather station
observations at St. Andrew’s, which the authors related to weather conditions at
Wreckhouse. The meteorological component of the study incorporated the conclusions
of earlier research by Janz, using data obtained between 1948 to1958. Further discussion
of the relationship between conditions at Wreckhouse and wind data from surrounding
stations is presented in chapter 5 of this report.
The majority of the events occurred with southeasterly winds ahead of warm fronts
or trowels, and could develop quickly. The phenomenon was a result of the cold air
becoming trapped between the advancing warm front and the high terrain a few miles
inland. With continued pressure from the warm air, the cold air was forced through the
natural funnel at much greater than normal velocity. It was proposed that a mechanism
similar to the Bernoulli affect could be the cause of the strong winds.
The majority of the abnormal winds originated from the east or southeast, ahead of
warm fronts, and diminished rapidly with the passage of the front. They occurred
predominately from the late fall to early spring with few or no events during the summer.
Wind speeds increased very rapidly over short periods of time, reaching 144 km/h (90
mph) with gusts to 190 km/h (120 mph). A total of 130 gale force events were
documented between 1956 and 1962, of which 84% originated from the east or southeast.
These winds were responsible for the delays in rail traffic.
55
Sutherland et al. (1963) stated that the abnormal winds producing Wreckhouse
Events were assisted by funneling along the flanks of the Red Rock Hills, Sugar Loaf Hill
and Table Mountain. The presence of the Horizontal Wave Forest at Red Rock Hills was
associated with the wind regime. The climatology of Wreckhouse events is discussed
further in chapter 5 of this report.
Sutherland et al. (1963) were primarily concerned with delays to rail traffic (Tables
4.1, 4.2, 4.3). Days with wind speeds in excess of 65 km/h (40 mph) were compared with
traffic delay data obtained from the office of the Superintendent of the Line of the CNR.
Train delays occurred on 44 days with gale force (or stronger) winds recorded at St.
Andrew’s, and on 13 days with lower wind speeds. All of the train delays occurred when
the wind was from the east, southeast, or south. Most of the gales occurred during the
months of November through March. Over the 8 year period, the 57 delays represent an
average of 7.1 per year.
As traffic was delayed on approximately 33 % of the number of days with gale force
or stronger winds, Sutherland et al. (1963) also looked at the number of consecutive
hours the winds were strong, hypothesizing that perhaps the strong winds did not last
very long, and therefore did not conflict with the train schedule. They concluded that
there was insufficient data to explain why train delays only occurred on some of the days
with strong winds, but not others, and why delays sometimes occurred when the winds
were not as strong (i.e. less than 65 km/h). The longest train delay was 19.5 hours, the
shortest 1.5 hours.
Table 4.1 Number of train delays by month and year in the Wreckhouse area,
1956 to 1962
Month
Year Jan Feb Mar Apr MayJun Jul Aug Sep Oct Nov Dec Total
1956 0 0 0 0 0 0 0 0 1 1 2 1 5
1957 1 3 2 1 0 0 0 0 0 0 1 2 10
1958 1 3 0 2 0 1 0 0 0 0 1 1 9
1959 2 0 3 0 0 0 0 0 0 0 2 0 7
1960 2 5 0 0 0 0 0 0 0 0 2 0 9
1961 3 0 1 0 2 0 0 0 0 0 0 0 6
1962 0 1 1 1 0 0 0 0 0 0 3 4 10
Total 9 12 7 4 2 1 0 0 1 1 11 8 56
56
Table 4.2 Days of strong winds in relation to the number of train delays 1956 to
1962
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
Days of strong winds 23 16 15 10 9 3 0 0 4 9 18 23 130
Days of delays with
winds over 40 MPH 6 9 6 3 2 0 0 0 1 2 7 8 44
Days of delays with
winds under 40 MPH 3 3 1 1 0 1 0 0 0 0 2 2 13
Table 4.3 Trains delays in comparison with wind direction 1956 to 1962
Wind Direction N NE E SE S SW W NW Total
Days of strong winds 0 0 27 82 9 7 2 3 130
Days of delays with
winds 40 MPH or over 0 0 14 27 5 0 0 0 46
Days of delays with
winds less than 40 MPH 0 3 2 7 1 0 0 0 13 Weather Engineering Corporation of Canada (1982) examined the cause of the
extremely high winds at St. Andrew’s and elsewhere in the Codroy Valley that damaged
Newfoundland and Labrador Hydro transmission towers along TL-214, with a goal of
assessing design and maintenance. Using the data obtained from the St. Andrew’s
weather station for the period 1953-1966, the frequency distribution and extreme values
of the wind speed were determined as well as return periods of extreme wind events and
the probability of occurrence of any wind speed.
Rawinsonde data from Argentia, obtained during severe storms, was used to
calculate wind speed frequency distributions for 305 m (1000 ft) elevation and compared
with the surface observations at St. Andrew’s. The results indicated the wind speeds at St.
Andrew’s were stronger at a given return period than were winds 305 m above the
ground, in contrast to normal conditions elsewhere.
This study downplayed the role of funneling or channeling of the winds through
gaps in the high terrain as the cause of the extreme winds. Using wind data from other
recording equipment, the study indicated areas of divergent flow off the Long Range
Mountains were also regions of severe winds. It was proposed these winds were a type of
57
fall-wind caused by the rapid downslope flow off the Long Range Mountains. When east
or southeast winds off the interior plateau of the Long Range Mountains reached the
escarpment, would drop-off quickly to the low lying areas at Wreckhouse and St.
Andrews. Local channeling of the wind through river valleys modified the winds but it
was essentially a downslope wind phenomena. The study investigated the relationship
between downslope wind storms in the Codroy Valley and the energy of the air stream.
Theoretical relationships were applied for two storms and the results correlated well with
observed winds and damage to transmission lines in the Codroy Valley. The study also
investigated the extreme gustiness of the downslope winds and concluded the Boyd gust
formula fitted the observations at St. Andrew’s to a good approximation.
The primary objective of this study was to assess the design of Transmission Line
214. Consideration of the data indicated that TL 214 should be designed to withstand an
extreme sustained wind speed of 177 km/h, with gusts to 235 km/h.
TRO Engineering (2002) conducted a further assessment of TL-214 for
Newfoundland and Labrador Hydro. Based primarily on the Weather Engineering
Corporation (1982) report, it was recommended that TL-214 be redesigned to withstand
gusts to 235 km/h, rather than the original design standard of 177 km/h for individual
gusts. TRO (2002) conducted a design analysis based on the higher gust value, focusing
on phase spacing, horizontal insulator swing, and conductor design. A central concern
was ensuring that conductors had sufficient weight so that they would not be displaced by
strong winds towards the cross-arms, as contact between the two would result in design
failure.
ADI Limited (1994) conducted a study of Wreckhouse winds and their effect on
truck traffic, to assess the cost effectiveness of a wind warning system. Warning signs
and markers have subsequently been installed along the highway. The intent of this study
was to assess the magnitude of accidents and delays, and to discuss remedial measures,
rather than to analyze the meteorological situation.
Over the five year period 1989-1993, ADI Limited (1994) documented 17
rollover/high wind blowoff accidents. Of these, only 9 (59%) occurred during the winter
months of November through March, suggesting that high winds are possible during any
season. The estimated average cost of each accident, based on insurance claims for
58
vehicles and cargo, was ca. $50,000 in 1993 (estimated by AJ Bell and Grant Ltd.,
Insurance Brokers, Halifax), equivalent to ca. $70,000 in 2006. The mean annual cost
estimate from 1989-1993 was $170,000, equivalent to $236,000 in 2006. These figures
do not include uninsured losses, and also refer only to the value of the hardware involved.
The cost of delays was also estimated by ADI Limited (1994). At Doyles, high
winds force westbound truckers to remain parked until the winds subside. The estimate
of 25 such events per year, each one lasting approximately 6 hours, affecting
approximately 100 trucks per event, produces a value of 15,000 truckers hours per year
lost in delays in each direction, for a total of 30,000 hours lost in delays per year. With
adjustment for inflation between 1993 and 2006, the total estimated loss by truck traffic
delay each year is ca. $1.9 million. This figure does not include delays to smaller, non-
commercial vehicles, or costs involved with response to accidents or road maintenance
and repair.
4.2 Archival Research – Western Star
The previous studies involved relatively short investigations of specific forms of
transportation and infrastructure. Although estimates for highway traffic delays for the
period 1989-1993 are broadly valid for 2006, given the meteorological data available (see
Chapter 5) and the similarity in driving practices and vehicle design, comparison of rail
and road delays would not produce a valid estimate of the amount of change resulting
from changed climatic factors. Consequently, efforts were made to investigate archival
sources, in an attempt to determine if accident and delay frequencies had changed
throughout the period of railroad operation. Any such changes could then be considered
in light of changes in railroad equipment and maintenance protocols.
The Western Star newspaper (based in Corner Brook) was the most constant
source of data concerning derailments and delays. Publication of the Western Star started
in April 1900, and has continued until the present. Due to time constraints, and the lack
of detailed archival cataloguing of the newspaper, it was decided to investigate three
sample periods of two years each. This involved studying all of the issues from 1901-
1902, 1931-1932, and 1951-1952. All references to train delays due to any climate or
weather-related cause for the line between Stephenville and port aux Basques were noted.
59
These dates were chosen because they avoided the World Wars (1914-1918,
1939-1945) which would have limited the type of information published in a newspaper.
The earlier volumes of the paper had a reasonable account of such local information, but
later volumes, particularly those from the 1950s, had expanded to include more
international news, advertisements, and current clothing fashions, at the expense of local
news.
The data from 1901-1902 indicated a total of 9 recorded delays. This figure
represents the lowest possible estimate, as only the most extensive delays would be
considered newsworthy. The most significant event occurred on 25-27 November 1901,
and involved storm surge damage as well as high winds:
Friday 29 November 1901 Vol. 2 No. 62 [p. 3] “TERRIFIC GALE Held up
Express Train AT CODROY! Monday’s express to connect with the S.S.
Glencoe was held up at Little River station all night. A terrific gale swept
through the Codroy valley and carried the waters of the ponds in clouds of
spray for hundreds of yards. It seemed as though rain was descending in
torrents whereas really the night was comparatively clear. It was hardly safe
to be moving from car to car on the train, the force of the wind being so
great as to almost lift a man off his feet. In view of last year’s accidents, in
which one train was blown from the track and burnt up and another entirely
derailed, the railway people are acting prudently in stalling the trains during
such peculiar weather conditions ...”
[p. 4] “TIDAL WAVE Visits West Coast. Great Damage to Railway. Not
for seventeen years has the West Coast been visited by such a tide as that
experienced on Wednesday forenoon. Fortunately the day was calm and
there was no swell on, otherwise stores and dwellings would have been
floating about … at Grand Bay, or, to be more accurate, at Barachois, about
five miles east of Port au Basques, the terminus of the railway, the wind
blew with great force and the trestle work and gravel bed succumbed to the
ceaseless lashing of the waves. The ballast was washed from under the ties
and piles for nearly a hundred yards and all traffic became suspended. The
60
express for St. John’s with the Glencoe’s mails and passengers was stalled at
Port au Basques and did not leave until 5 o’clock yesterday afternoon,
reaching here shortly after four o’clock this morning.
“The express from St. John’s to connect with the Glencoe was held up at
Little River Wednesday night and was unable to reach P.A.B. The
passengers and mails were transferred to a train on the opposite side of the
washout and conveyed to Port au Basques, where they arrived at 5 p.m.
yesterday. The Glencoe left an hour or two later for North Sydney.”
In contrast, study of the issues from 1931 and 1932 produced no references to
storm activity or related delays. One article did comment upon heavy winds and snow at
Port aux Basques, but specifically mentioned that this did not affect the train schedules.
Study of the 1951-1952 issues revealed discussion of three storms sufficient to
cause damage and delay to railway traffic. The 29 June 1951 issue (p. 5) also reported
that,
“Two Men Badly Injured When Gale Blows Truck Over On The Highway.
St. Andrews – (Special) – An accident occurred on the Trans-Canada
Highway last Sunday when a truck turned over and two men were badly
injured. It is reported that the truck blew over during a severe southeast gale
which raged over the Valley that day. This is the first accident to occur on
the new highway.”
The low totals for delays recorded in the Western Star for these sample years
(between 0 and 4.5 per year for the three time periods) contrast with the annual average
of 7.1 delays per year noted by Sutherland et al. (1963). Improvements in engine design,
weather forecasting, and track maintenance would be expected to result in decreasing
total delays over time, under a regime of consistent climate. However, the low totals
more likely reflect a lack of reporting of incidents in the Western Star, rather than an
actual increase in the number of delays. Comparison of the 3 delays reported over the
1951-1952 period in the Western Star with the 7.1 yearly average noted between 1956
61
and 1962 suggests that under-reporting is more likely than a rapid increase in gale
frequency.
4.3 Canadian National Archives
Delays to rail traffic should primarily be recorded by the operators.
Consequently, inquiries were made to locate the CN archival material relevant to the
Newfoundland Railway, although previous efforts in this regard in conjunction with other
studies (e.g. Catto and Hickman, 2004; Catto, 2006b) had proven unsuccessful.
The CN archives are part of the Library and Archives Canada collection in
Ottawa (Record Group 30). The available records appear to consist of the Newfoundland
Railway Records for 1881, 1884, and 1904-1946, specifically including:
1) income and expenditure graph 1904-1946
2) tariffs and pay book 1915-1949
3) photographs and time table 1928
Initial investigation, facilitated by Library and Archives Canada staff, revealed no
material pertinent to delays of traffic, or to repairs of the line. The available records
concerned primarily tariffs, timetables, price books of supplies, and bills paid. Further
research would entail diligent analysis of all the materials, but the preliminary
investigations suggest that no archival materials pertaining to delays in traffic have been
maintained.
4.4 Other Archival Research
On advice from Library and Archives Canada, the Merrilees Transportation
Collection website, part of the Library and Archives Canada website
(http://www.collectionscanada.ca/trains/h30-6000-e.htm) was consulted, but yielded no
useful information. Further research in the archives of the Canadian Railroad Historical
Association, assisted by Josee Vallarand, archivist; the Provincial Archives of
Newfoundland and Labrador (including the Reid Collection); the Railway Coastal
Museum (of NL), assisted by Pam Correstine, former archivist; the AC Hunter Library;
and the City of St. John’s archives also proved unsuccessful.
62
Search at the Provincial Archives of Newfoundland and Labrador revealed a
single item of potential interest. File 321 “Reid Nfld Railway, Statements, 1902-1919”, in
addition to containing general statements of expenses such as maintenance of the entire
railway line, also contains a chart entitled “Data – Reid Newfoundland Railway” which
lists the miles of track, tons of freight carried, passengers carried, tie renewals, and other
data for 1902 to 1919. It also lists train derailments, for the entire line, between 1904 and
1919. Derailment totals varied from 13 (1908) to 94 (1918). Neither the chart nor
anything else in the file specifies the cause of the train derailments. The high totals,
however, do suggest that train derailments were common occurrences, and thus perhaps
were not comprehensively reported in newspapers at the time.
4.5 Summary
• At present, it is not possible to assess if any change has occurred in the
frequency of Wreckhouse Events, as judged from resultant delays to transportation,
over the historical record. The available archival data appears to be inadequate for
such an assessment.
• Recent events, documented by meteorological data, are discussed in Chapter 5.
Historically, Wreckhouse Events have been known and respected since the initial
railway construction period.
• The most recent cost estimates of disruption to highway traffic, summarized by
ADI Limited (1994), suggest that accidents cost ca. $236,000 annually, and delays
cost a further $1.9 million (as measured in 2006 dollars). Thus, the cost of
Wreckhouse Events to the provincial economy is in excess of $ 2.1 million
annually.
• This figure only includes insured losses and delays, and does not include delays
or damage to smaller, non-commercial vehicles, or costs involved with response to
accidents or road maintenance and repair.
63
5. Climate and Meteorological Analyses
Dale Foote and Dermot Kearney
5. 1. Introduction
Southwestern Newfoundland and the Cabot Strait are vital to maintaining a link
between the Island of Newfoundland and the rest of Canada. It is important that regular
ferry service into the harbour at Port aux Basques and traffic movement via the Trans-
Canada Highway be maintained. Highway traffic is often disrupted in the Wreckhouse
area due to severe localized winds and ferry traffic due to high winds and rough seas in
the Cabot Strait.
An analysis of the region’s wind and wave climatology over the past 35 to 50 years
has been used to determine if there are any significant changes in wind velocity, duration
and frequency and wave height. Several data sources were exploited:
1. Environment Canada’s National Meteorological Data Archives.
2. The AES40 North Atlantic Wind and Wave Climatology.
3. Environment Canada’s 100 Year (1901 - 2000) Tropical Cyclone Climatology for
cities.
The southwest coast of Newfoundland and the adjacent waters of the Cabot Strait are
located near the primary storm tracks of North America. Storms track south or southeast
of the Cabot Strait or to the west or northwest through the Gulf of St. Lawrence toward
Labrador or the Labrador Sea. Frequent and intense storm activity is often associated
with low pressure systems approaching the Cabot Strait from the south. This is primarily
due to the proximity of the North American landmass to the warm waters of the Gulf
Stream. When cold air originating over the continental landmass, clashes with warmer
moist air over the Gulf Stream, frequent cyclogenesis occurs. This makes the Gulf Stream
off the eastern seaboard of the United States the most active area for cyclogenesis in the
North Atlantic. When these storms move northeastward toward Atlantic Canada they can
rapidly intensify in a favourable oceanic environment.
64
The interaction of these weather systems with the high terrain over southwestern
Newfoundland can cause complex wind patterns, prevailing wind at Port aux Basques to
be easterly, which is opposite to that of most places in North America, and severe
downslope wind storms observed at Wreckhouse and St. Andrew’s.
Downslope wind storms are observed on the lee side of major mountain ranges
such as the Canadian Rockies and the European Alps. These storms also occur on much
smaller geographical scales as observed at Wreckhouse in southwestern Newfoundland
and les Suetes winds at Cheticamp on Cape Breton Island (Desjardins, 1995). They occur
when stably stratified air is forced to rise over a topographic barrier causing oscillations
or disturbances in the mean flow. Depending on the height and shape of the terrain as
well as the vertical wind and temperature structure of the lower atmosphere, different
wind regimes can result including the Wreckhouse and les Suetes winds. During these
events air is forced over a topographical barrier and upon reaching a supercritical flow
(Froude number >1), will accelerate on the lee side of the barrier. As the disturbance
descends and accelerates intense winds can be concentrated at the ground, analogous to a
hydraulic jump, after which the flow begins to adjust back to a subcritical flow (Froude
number <1). Results of numerical model simulations on the les Suetes in Cape Breton
indicate a hydraulic analogy is applicable to describing that wind phenomena.
Simulations of the Wreckhouse wind events would likely give a similar result.
In addition to the baroclinic synoptic scale storms that develop in the mid
latitudes and move through the study area, the Atlantic tropical weather season between
June and November, and the associated tropical storms and hurricanes, may affect the
Cabot Strait region. Most of these storms weaken as they move northward and enter
cooler waters and some transition into an extra-tropical low or post-tropical system.
Whether storms originate in the mid latitudes or tropical areas of the Atlantic
Ocean, the Cabot Strait region is prone to frequent storms with high winds, heavy
precipitation, large waves and storm surges.
65
5.2. Data Sources
5.2.1 Environment Canada’s National Meteorological Data Archive
Environment Canada (EC) maintains the archive of meteorological data in Canada
and this study uses data from several sites contained in the archive: Port aux Basques
(WZB), Burgeo (WBF), Stephenville (YJT), Sydney (YQY), Wreckhouse (XWR) and St.
Andrew’s. Observation site history discussions are given below.
Figure 5.1. Map showing the locations of wind measurement stations used in the
Southwest Newfoundland Cabot Strait Transportation Study.
The weather observations taken at Port aux Basques have a long and dynamic
history. The earliest reports date back to 1929 when the observations were taken at the
old Telegraph and Cable office. They were taken twice daily from an anemometer on top
of a 150 foot cliff on a 20 foot tower. There were some meteorological inspector reports
from the early 1930s but it appears the location of the observations remained at the
telegraph office. No inspector’s reports were found for most of the 1930s and all of the
1940s. In 1955 the station was moved to the Loran transmitting station approximately 1.5
66
miles southwest of the Canadian National Railway station in Port aux Basques. From
1955 until June 1966 there were no wind measurements taken in Port aux Basques. In
June of 1966 the U2A anemometer at St. Andrew’s was relocated to Port aux Basques on
a hill 56 feet ASL and placed on a 43 ft high tower. The hill sloped away to the ocean in
all directions except north and northeast where the terrain gradually rose to 200 feet ASL
approximately three quarters of a mile away. There were no changes to the observation
location until August 1983 when it was moved, 800 ft to the north northeast, to its current
location. On this site the anemometer was 32 metres higher on the hill and placed on a 10
meter tower.
Meteorological observations at the Stephenville Airport began in January 1953
when the American military operated the facility as Harmon Field. From 1953 to June
1966 there were no inspector’s reports available. The Americans operated two wind
monitoring systems located at each end of the 10,000 foot runway 09-27. In 1966 the
Department of Transport managed the airport and a new anemometer was temporary
installed on a 6 metre tower until later in the year, likely September (MSC
Meteorological Inspector Brian Hulan, personal communication). The anemometer
remains at the same location today.
Meteorological observations in Burgeo began in the summer of 1966 and continue
today at the original location. The height of the anemometer has remained constant at 10
metres however in the summer of 1969 the type was changed from a 45B to a U2A. The
anemometer rests on a 10 metre tower on small hill 75 ft above MSL which is 40 feet
above station elevation. The site is well exposed in all directions.
Sydney Airport, as with Port aux Basques and Stephenville, has an inconsistent
anemometer height and location history (see Karn, 2004). From June 1950 to August
1968 the anemometer location and height were changed several times. On August 31,
1968 the wind observations began at the present location and height.
Wreckhouse, located northwest of Port aux Basques in the Codroy Valley, is an
open and barren stretch of land where trains were once blown off their tracks by severe
local windstorms. Now it is usually large transport trucks that fall victim to these
powerful winds (see Chapter 4). The place name Wreckhouse has thus become
synonymous with the Wreckhouse wind phenomena.
67
The meteorological observations, taken at Wreckhouse, have been consistent in
location and height since January 2000. Between 1953 and 1966 the observations were
taken at St. Andrew’s and in the 1980s and early 1990’s at the nearby Starlight Lounge.
These sites are in different areas of the Codroy Valley and also experience the
Wreckhouse Effect.
5.2.2 AES40 North Atlantic Wind and Wave Climatology
The AES40 data set was developed at Oceanweather a specialized consulting firm
serving the coastal and ocean engineering communities with support from the Climate
Research Branch of Environment Canada. The hindcast involved the kinematic reanalysis
of all significant tropical and extra-tropical storms in the North Atlantic for the period
1954-2003. This data set has the advantage of being consistent in its temporal and spatial
resolution and with the height of its predicted wind. There was no need for
homogenization of the data and changes in the wind climatology will be attributable to
the forecast climatology.
5.2.3 Environment Canada 100 Year (1901 - 2000) Tropical Cyclone Climatology for
Cities
Environment Canada has analyzed 100 years of tropical cyclone tracks through
Atlantic Canada and recorded when these storms pass within 260 kilometres of 33
different locations. It was determined in 1986 by Barks and Richards of EC Atlantic that
tropical cyclones coming within 260 km of a location have a high probability of
producing gale force winds at that location.
We have decided to use the criteria of a tropical cyclone passing within 260
kilometres of Sydney or Port aux Basques to indicate when a tropical cyclone had the
greatest probability of impacting travel through the Cabot Strait or southwestern
Newfoundland.
68
Figure 5.2 Winter Storm Tracks
(A) Great Lakes Lows (B) Cape Hatteras/Cape Cod Lows
(C) Gulf of Mexico Lows
Joint Frequency Distribution
Burgeo, NL Complete History (1966-2004)
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
6.91
3.56 2.91
4.59
6.02
14.05
6.54
2.98
2.43 3.06
2.99
4.70
5.53
13.33
9.84
6.07
4.50
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Figure 5.3 Wind speeds and directions, Burgeo
69
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) Complete History
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.32
3.86 2.27
2.35
5.95
21.71
4.93
2.40
2.18 3.18
2.40
2.01
3.53
13.66
13.20
8.91
4.14
Wind Speed ( kmh)
1 11 21 31 41 51
Figure 5.4 Wind speeds and directions, Port aux Basques
Joint Frequency Distribution
Stephenville A, NL (1967-2004) Complete History
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
7.54
3.63 1.77
7.63
10.42
8.48
2.04
1.49
1.91 4.66
3.10
5.29 12.07
14.24
6.80
5.24
3.71
Wind Speed ( kmh)
1 11 21 31 41 51
Figure 5.5 Wind speeds and directions, Stephenville
70
Joint Frequency Distribution
Sydney A, NS (1967-2004) Complete History
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.36
7.99
3.13
2.96
2.44
3.43
2.44
2.77
3.56
9.31 10.44
11.49
9.28
12.20
6.06
4.61
4.54
Wind Speed ( kmh)
1 11 21 31 41 51
Figure 5.6 Wind Speeds and directions, Sydney
5.3 Analysis
5.3.1 Inhomogeneous data
Inhomogeneous data is the result of an inconsistent measurement history, i.e.
changes in location, measurement technique or instrumentation. As documented in the
site histories section some data used for this report has such inconsistencies. Two
methods of correcting for non homogenous data were considered for this report.
1. Using the ratio of monthly averages before and after a modification in the sampling
methodology to develop a correction factor to apply to one portion of the data. This
method works well when only one variable changes. When there are changes occurring
in climatological and sampling methods at the same time it is difficult to quantify what
percent of change is due to instrumentation.
71
2. Correction of the wind speed using the standard atmosphere approximation. This
method does not incorporate frictional effects, changes in horizontal location or
atmospheric profiles that deviate from the standard atmosphere, for example stable or
unstable lower level lapse rates.
A robust analysis of the magnitudes of the various components that may
contribute to a step change associated with an in-homogeneity is beyond the scope of this
study. Adjustment of monthly means based on the ratio of monthly averages before and
after a measurement change is susceptible to being confused with natural interannual
variability. Therefore any analysis on long-term trends will be confined to the portions of
the climatology with minimal change in observing routine and homogenization of the
wind data will not be attempted.
All the trend analysis values in the paper were obtained using the Kendall’s tau
test for trend and associated p-values.
5. 3.2 Historical measured winds
The prevailing wind over North America is generally westerly. However, local
topography has an influence on the wind direction at any given location. The individual
stations sites for our study area have a wide variety of mean annual wind speeds and
directions.
Burgeo and Port aux Basques are influenced by cold air dammed along the
mountains and funnelling from the fjords along the south coast of Newfoundland. These
topographical effects cause prevailing winds, especially during the summer, to be
easterly. Doherty (1991) described a favourable meteorological pattern that causes the
coastal easterlies often observed at Port aux Basques and Burgeo. “Flows from the south
or southwest combine with cold sea surface temperatures to produce very stable air in
low levels. The stable flow is blocked by the hills along the south coast of Newfoundland
resulting in easterly surface winds along the coast”. (Doherty, 1991). Burgeo has a high
occurrence of easterly winds especially during the warmer months. Due to higher
topography near Port aux Basques than Burgeo, Port aux Basques experiences more
72
episodes of easterly winds. These terrain effects will likely have an impact in determining
any long term trends in the wind climatology of the southwest coast.
Stephenville Airport also has strong topographical forcing on its prevailing winds
but not as obvious as Burgeo or Port aux Basques. St. Georges Bay lies directly to the
southwest of the observing station causing the prevailing southwesterly winds to blow
relatively unimpeded. However the mountains that lie to the north and east of the
observing station increase the frequency of easterly winds in two ways.
• Redirection of synoptic scale flow ahead of an approaching low pressure system
from the south or southeast direction to the east to northeast direction.
• Katabatic/drainage winds can develop and flow down the mountainsides under
clear skies and a weak synoptic scale isobar pattern.
Sydney Airport’s prevailing wind direction is from the southwest quadrant with
the wind blowing between south and west 54% of the time. The remaining 46% is spread
relatively evenly between west northwest and south southeast. Sydney Airport is the least
topographically influenced observing station included in this study (Karn, 2004).
5.3.2.1 Yearly Mean Wind Speeds
Station Trend (kph/Year) N p-value**
Burgeo (WBF) -0.14 35 <0.001
Port aux Basques (WZB)
+0.078 38 0.003
Stephenville (YJT)
+0.025 38 0.208
Sydney (YQY) -0.13 36 <0.001
** Significant at 5% level. Table 5.1 Yearly mean wind speeds
Yearly mean wind speeds were calculated for all for observing stations by
summing all hourly observations for a calendar year and dividing by the number of
observations. The results are presented in Table 5.1. All statistical significance tests
were conducted at the 5% level.
73
Figure 5.7 Yearly average wind speed, Burgeo
Wbf Yearly Average Wind Speed
0
5
10
15
20
25
30
35
40
1960 1970 1980 1990 2000 2010
Year
Kp
h
Figure 5.8 Yearly average wind speed, Port-aux-Basques
Wzb Yearly Average Wind Speed
0
5
10
15
20
25
30
35
40
1960 1970 1980 1990 2000 2010
Year
Kp
h
Figure 5.9 Yearly average wind speed, Stephenville
Yjt Yearly Average Wind Speed
0
5
10
15
20
25
30
35
40
1960 1970 1980 1990 2000 2010
Year
Kp
h
74
Figure 5.10 Yearly average wind speed, Sydney
Yqy Yearly Average Wind Speed
0
5
10
15
20
25
30
35
40
1960 1970 1980 1990 2000 2010
Year
Kp
h
The results for Burgeo and Sydney Airport indicate a statistically significant
decreasing trend while Port aux Basques has a statistically significant increasing trend.
The p-values for these trend lines were very small. The slight increasing trend at
Stephenville is not statistically significant.
5.3.2.2 Yearly Maximum Wind Speeds
Station Trend (kph/Year) N p-value**
Burgeo (WBF) <.001 35 0.81
Port aux Basques (WZB)
+0.50 38 0.023
Stephenville (YJT)
0 38 0.69
Sydney (YQY) -0.40 36 0.002
** Significant at 5% level. Table 5.2. Yearly maximum wind speeds
Yearly maximum wind speeds were determined for the stations by selecting the
maximum wind speed for a calendar year. The results are presented in Table 5.2. All
significance tests were conducted at the 5% significance level.
The overall trends for yearly maximum wind speeds in table 2 are consistent with
the yearly mean wind speeds in table 1 where the results for Burgeo and Sydney Airport
indicated a decreasing trend while Port aux Basques had an increasing trend. However,
75
Figure 5.11 Yearly maximum wind speed, Burgeo
Wbf Yearly Maximum Wind Speed
0
20
40
60
80
100
120
140
1960 1970 1980 1990 2000 2010
Year
Kp
h
Figure 5.12 Yearly maximum wind speed, Port aux Basques
Wzb Yearly Maximum Wind Speed
0
20
40
60
80
100
120
140
1960 1970 1980 1990 2000 2010
Year
Kp
h
Figure 5.13 Yearly maximum wind speed, Stephenville
Yjt Yearly Maximum Wind Speed
0
20
40
60
80
100
120
140
1960 1970 1980 1990 2000 2010
Year
Kp
h
76
Figure 5.14 Yearly maximum wind speed, Sydney
Yqy Yearly Maximum Wind Speed
0
20
40
60
80
100
120
140
1960 1970 1980 1990 2000 2010
Year
Kp
h
the slight decreasing trend at Burgeo is not considered to be statistically significant at the
5% level whereas Sydney’s decreasing trend is statistically significant with a p-value of
.002. There was no trend observed in Stephenville's data however it is not statistically
significant at the 5% level. Both Port aux Basques and Sydney’s trends are in the
opposite direction but both are statistically significant at the 5% level.
5.3.2.3 Annual Wind Speed Category Percentages
Annual wind speeds are divided into four categories: <19 knots, strong [19 to 33
knots], gale force [34 to 47 knots] and storm force [48 to 63]. Sustained hurricane force
winds rarely happen so they have not been included in these figures. However when
sustained storm force winds are measured they are often accompanied by hurricane force
wind gusts.
Table 5.3 contains results of the statistical analysis on the annual wind data using
the Kendall Tau test for trend. The results show that the majority of the change that has
been analyzed in the annual mean wind speeds is a result of a redistribution of winds in
the <19 knots and the strong categories. Changes in gale force winds have had less
obvious trends and they tend to be an order of magnitude smaller. Trends in storm force
winds are 2 orders of magnitude smaller.
77
Table 5.3.
Station/Category Trend (%/Year) N p-value**
Burgeo < 19 knots
+0.250 35 <0.001
Burgeo Strong
-0.233 35 <0.001
Burgeo Gale force
-0.011 35 0.120
Burgeo Storm force
0 35 0.629
Port aux Basques < 19 knots
-0.19 38 0.066
Port aux Basques Strong
+0.147 38 0.019
Port aux Basques Gale force
+0.043 38 0.007
Port aux Basques Storm force
+0.005 38 0.001
Stephenville < 19 knots
-0.021 38 0.249
Stephenville Strong
+0.025 38 0.247
Stephenville Gale force
< -0.001 38 0.939
Stephenville Storm force
< -0.001 38 0.628
Sydney < 19 knots +0.15 36 <0.001
Sydney Strong
-0.15 36 <0.001
Sydney Gale force
-0.005 36 0.001
Sydney Storm force
Insufficient Data
** Significant at 5% level. 5.3.2.4 Seasonal Wind Speed Category Percentages
Seasonal wind speed category graphs are presented in Appendix B and divided
into four categories: <19 knots, strong [19 to 33 knots], gale force [34 to 47 knots] and
storm force [48 to 63]. Sustained hurricane force winds have not been included. The
seasonal wind categories were calculated using climate data counts of the number of
78
times a wind speed fell within the desired category. The seasonal totals were obtained
and divided by the total number of observations and multiplied by 100 to obtain the
percentage of occurrence. Tables 5.4A to 5.4D contain results of the statistical analysis
on the seasonal wind data using the Kendall Tau test for trend. The majority of change is
due to the redistribution of winds between the <19 knots and the strong wind categories.
This is particularly evident in the summer and fall and is due to the seasonal cycle to
lower wind speeds. In the warmer months the higher wind speed categories have
insufficient data to determine a trend for most stations
5.3.3 Comments on the Seasonal Wind Speed Categories
The analysis for Burgeo indicates a statistically significant increasing trend in the
<19 knots category and a statistically significant decreasing trend for most of the higher
wind categories for all months. The exceptions occur in the spring and fall where the gale
wind category has a decreasing trend that is not statistically significant.
The analysis for Port aux Basques indicates a decreasing trend in the <19 knots
category and an increasing trend for the higher wind speed categories. The gale force
wind category indicates a statistically significant increasing trend for all seasons.
When the trend analysis is applied to the data between 1990 and 2002 for Port aux
Basques, there is a statistically significant decreasing trend for the <19 knots category
and a statistically significant increasing trend for the higher wind categories for most
seasons.
The analysis for Stephenville indicates a decreasing trend for the <19 knots
category and increasing trend for the higher wind speed categories however the trends in
all months are not statistically significant at the 5% level.
The analysis for Sydney indicates there is a statistically significant increasing
trend in the <19 knots category and a statistically significant decreasing trend for the
higher wind categories for all months.
79
Table 5.4A. Seasonal Trends DJF
Station/Category Trend
(%/Season)
N P-Value**
Burgeo < 19 knots
+.242 35 0.010
Burgeo Strong
-0.224 35 0.009
Burgeo Gale force
-0.038 35 0.10
Burgeo Storm force
0.00 35 0.579
Port aux Basques < 19 knots
-0.151 38 0.289
Port aux Basques Strong
+0.102 38 0.320
Port aux Basques Gale force
+0.10 38 0.024
Port aux Basques Storm force
+0.002 38
0.260
Stephenville < 19 knots
-0.082 38 0.204
Stephenville Strong
+0.079 38 0.148
Stephenville Gale force
Insufficient data
Stephenville Storm force
Insufficient data
Sydney < 19 knots
+0.224 36 0.001
Sydney Strong
-0.212 36 0.002
Sydney Gale force
-0.012 36
<0.001
Sydney Storm force
Insufficient data
** Significant at 5% level.
80
Table 5.4B. Seasonal Trends MAM
Station/Category Trend
(%/Season)
N P-Value**
Burgeo < 19 knots
+0.254 35 0.002
Burgeo Strong
-0.256 35 0.001
Burgeo Gale force
-0.008 35 0.56
Burgeo Storm force
Insufficient data
Port aux Basques < 19 knots
-0.205 38 0.105
Port aux Basques Strong
+0.152 38 0.133
Port aux Basques Gale force
+0.027 38 0.036
Port aux Basques Storm force
Insufficient data
Stephenville < 19 knots
-0.012 38 0.831
Stephenville Strong
+0.008 38 0.870
Stephenville Gale force
+0.007 38 0.870
Stephenville Storm force
Insufficient data
Sydney < 19 knots
+0.196 36 <0.001
Sydney Strong
-0.196 36 <0.001
Sydney Gale force
Insufficient data
Sydney Storm force
Insufficient data
** Significant at 5% level.
81
Table 5.4C. Seasonal Trends JJA
Station/Category Trend
(%/Season)
N P-Value**
Burgeo < 19 knots
+0.129 35 <0.001
Burgeo Strong
-0.107 35 0.001
Burgeo Gale force
Insufficient data
Burgeo Storm force
Insufficient data
Port aux Basques < 19 knots
-0.010 38 0.025
Port aux Basques Strong
+0.100 38 0.021
Port aux Basques Gale force
Insufficient data
Port aux Basques Storm force
Insufficient data
Stephenville < 19 knots
-0.003 38 0.744
Stephenville Strong
+0.002 38 0.890
Stephenville Gale force
Insufficient data
Stephenville Storm force
Insufficient data
Sydney < 19 knots
+0.066 36 <0.001
Sydney Strong
-0.064 36 <0.001
Sydney Gale force
Insufficient data
Sydney Storm force
Insufficient data
** Significant at 5% level.
82
Table 5.4D. Seasonal Trends SON
Station/Category Trend
(%/Season)
N P-Value**
Burgeo < 19 knots
+0.274 35 <0.001
Burgeo Strong
-0.244 35 <0.001
Burgeo Gale force
-0.012 35 0.382
Burgeo Storm force
Insufficient data
Port aux Basques < 19 knots
-0.156 38 0.084
Port aux Basques Strong
+0.117 38 0.132
Port aux Basques Gale force
+0.032 38 0.018
Port aux Basques Storm force
Insufficient data
Stephenville < 19 knots
-0.009 38 0.660
Stephenville Strong
+0.012 38 0.610
Stephenville Gale force
Insufficient data
Stephenville Storm force
Insufficient data
Sydney < 19 knots
+0.149 36 0.002
Sydney Strong
-0.145 36 0.002
Sydney Gale force
Insufficient data
Sydney Storm force
Insufficient data
** Significant at 5% level.
83
Figure 5.15
Burgeo Annual Wind Speed Categories
% Occurrence vs. Year
0.01
0.1
1
10
1001970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
Year
% < 19
% Strong
% Gale
% Storm
Figure 5.16
Port aux Basques Annual Wind Speed Categories
% Occurrence vs. Year
0.01
0.1
1
10
100
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
Year
% < 19
% Strong
% Gale
% Storm
84
Figure 5.17
Stephenville Airport Annual Wind Speed Categories
% Occurrence vs. Year
0.01
0.1
1
10
100
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
Year
% < 19
% Strong
% Gale
% Storm
Figure 5.18
Sydney Airport Annual Wind Speed Categories
% Occurrence vs. Year
0.01
0.1
1
10
100
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
Year
% < 19
% Strong
% Gale
% Storm
85
5.4 Transportation Interruption Index
Quantitative analysis of long-term trends in mean, maximum and categorical
winds does not address the issue of wind event duration. To investigate the possibility of
long-term trends in wind event duration, and the relative strength of those events, we
have developed a Transportation Interruption Index to help quantify the potential a given
year had to interrupt transportation through the Cabot Strait. In our index a wind event is
defined as lasting three hours and having a minimum wind speed of 63 kph. The
maximum wind speed is then multiplied by the mean wind speed and the resulting
product is multiplied by the duration. The total is then divided by a scaling factor of
11,907, the minimum value attainable from the above calculation. Therefore the
minimum value of the event, TIIe, is 1. The TIIe for the calendar year are then summed to
create the TII. This formula is also described below:
TIIe = ((Max Wind Speed)*(Mean Wind Speed)*(Duration))/11907
TII = ∑TIIe
The TII for Port aux Basques, Burgeo, Stephenville and Sydney are shown in
Figures 5.19 to 5.22. The results for Port aux Basques are further broken down to their
westerly and easterly components in Figures 5.23 and 5.24). The trend analysis for the
TII is shown in Table 5.5.
It is interesting to note the high interannual variability in the TII westerly
component compared to the relatively benign easterly. This graph shows quantitatively
that although the easterly winds are of concern for the Wreckhouse area, it is the
westerlies that have the greatest potential to produce stormy conditions in the Cabot
Strait.
86
Yearly Port aux Basques TII
(1966, 1997 & 1998 removed)
0
50
100
150
200
250
1960 1970 1980 1990 2000 2010
Figure 5.19
Yearly Burgeo TII
(1967-69 removed)
0
50
100
150
200
250
1960 1970 1980 1990 2000 2010
Figure 5.20
Yearly Stephenville TII
0
50
100
150
200
250
1960 1970 1980 1990 2000 2010
Figure 5.21
Yearly Sydney TII(1966-68 removed)
0
50
100
150
200
250
1960 1970 1980 1990 2000 2010
Figure 5.22
87
Figure 5.23 Transportation Interruption Index for Wreckhouse, Westerly winds
Yearly WZB TI Index - Westerly Wind
(1966, 1997 &1998 removed)
0
50
100
150
200
250
1960 1970 1980 1990 2000 2010
Year
TII
Figure 5.24 Transportation Interruption Index for Wreckhouse, Easterly Winds
Yearly WZB TI Index - Easterly Wind
(1966, 1997 &1998 removed)
0
50
100
150
200
250
1960 1970 1980 1990 2000 2010
Year
TII
88
Table 5.5.
Station Trend (per Year) N p-value**
Burgeo -1.13 35 0.002
Burgeo++
-0.011 33 0.988
Port aux Basques +2.40 36 0.004
Stephenville 0 38 0.850
Sydney -0.139 36 < 0.001
** Significant at 5% level. Burgeo++ - For comparison the extreme data for 1971 & 72 has been removed.
5.5 Wreckhouse Area
Port aux Basques and Wreckhouse are geographically close. However, the
topography of southwestern Newfoundland impacts the winds measured at both stations
differently, for identical synoptic weather patterns. Chapter 4 contains information on
past wind studies of the area that highlight the importance of the Wreckhouse wind.
For years the residents of southwestern Newfoundland and forecasters at the former
Newfoundland Weather Centre have known that a relationship exists between easterly
winds measured at Port aux Basques and the downslope winds present in the Wreckhouse
area. This relationship is shown in a graphical manner in Figures 5.25 and 5.27. The data
plotted are hourly observations and the corresponding wind speeds at both observing sites
from 2000 to 2004. The wind speeds would be very close in magnitude without the
topographical effect caused by the mountains and coastline and the data would be plotted
with a slope near one.
Figure 5.25 shows the relationship between the winds at Port aux Basques and
Wreckhouse for wind directions northeast to southerly when the mountains along the
south coast induce a downslope wind at Wreckhouse. This leads to the general
relationship that the winds at Wreckhouse are stronger than those at Port aux Basques for
these directions.
Figure 5.26 is for the westerly direction and shows that the winds at Port aux Basques
generally blow stronger than the winds at Wreckhouse for a similar synoptic scale
weather pattern. This is likely caused by the funnelling and channelling of westerly
89
Figure 5.25 Relationship between Port aux Basques (WZB) and Wreckhouse (XWR) winds, easterly direction
WZB vs XWR Wind Speed
Direction 060-180
0
20
40
60
80
100
120
140
0 20 40 60 80 100 120 140
Wzb Windspeed (kph)
Xw
r W
ind
sp
eed
(kp
h)
Figure 5.26 Relationship between Port aux Basques (WZB) and Wreckhouse (XWR) winds, westerly direction
WZB vs XWR Wind Speed
Direction 230-340
0
20
40
60
80
100
120
140
0 20 40 60 80 100 120 140
Xw
r W
indspeed (kph)
Wzb Windspeed (kph)
90
Figure 5.27 Relationship between Port aux Basques and Wreckhouse winds, easterly storm peaks
Figure 5.28 Inferred Wreckhouse Peak Winds, 1966-2004
C4
xwr wind
2002-04
1999-01
1996-98
1993-95
1990-92
1987-89
1984-86
1981-83
1978-80
1975-77
1972-74
1969-71
1966-68
140
130
120
110
100
90
80
Inferred Wreckhouse Peak Wind
Wzb vs Xwr Easterly Storm Peaks
with Wzb Speed >=57 kph
y = 0.8139x + 42.165R
2 = 0.6123
0
20
40
60
80
100
120
140
0 20 40 60 80 100 120 140
Wzb Wind Spd (kph)
Xw
r W
ind
Sp
d (
kp
h)
91
winds through the Cabot Strait and the exposure of the Port aux Basques area to this wind
direction.
Figure 5.27 displays the relationship differently. Wreckhouse events were identified
and the maximum hourly winds at the Port aux Basques observing station was paired
with the maximum hourly winds at the Wreckhouse observing station. It should be noted
that this is a relationship between hourly winds. There were no gusts analyzed, no special
observations included and some outliers were removed.
The linear regression line equation was used to infer the history of Wreckhouse winds
from the Port aux Basques wind observation data and the results are presented in Figures
5.28 and 5.29. They show considerable inter-annual and inter-decadal variability in the
frequency of Wreckhouse events and the maximum sustained wind expected. However
there are no long term increasing or decreasing trends present in the data.
Wreckhouse Event Total Yearly Hours (1966, 1997 &1998 Removed)
0
100
200
300
400
500
1960 1970 1980 1990 2000 2010
Year
Ho
urs
Figure 5.29 Wreckhouse Wind event total yearly hours. See Chapter 7 for further
discussion.
92
5.6 Wreckhouse Area Wind Climatology
St. Andrew’s 1953-May 1966
Wreckhouse 2000-2004
In Figures 5.30 to 5.35 a Wreckhouse wind event is defined as having occurred if
the mean wind speed reached 75 km/h or more and from directions 080o clockwise to
170o inclusive. Multiple Wreckhouse events could occur for the same synoptic system if
the duration of an event was interrupted by 3 or more hours of lighter wind speeds.
Wreckhouse events have been observed to last for 16 hours at St. Andrew’s and 22 hours
at Wreckhouse. The figures show most Wreckhouse events last longer than 3 hours. Gust
data has not been included.
The annual distribution of Wreckhouse events at St. Andrews’ shows much
variability ranging from 4 events in 1955 and 1957 to 15 in 1963. Similar variability is
observed in six years of data from the Wreckhouse observing station. There were also
more events observed at Wreckhouse however these stations should not be compared.
The St. Andrew’s data was collected from manned observations and the Wreckhouse data
from an automatic weather station. Both stations are separated by several kilometres and
used different wind measuring instruments and recording periods.
The monthly distribution of Wreckhouse events is very similar at both locations
and this is expected. Wreckhouse events occur most often in the winter and early spring
with little or no events during the summer. This is due to the strengthening of the jet
stream and synoptic weather systems in the winter and a weakening during the summer.
Meteorologists in Atlantic Canada have known that Wreckhouse windstorms
mainly occur with southeast winds ahead of low pressure systems that track west or
northwest of the Cabot Strait and much less frequently for ones that track to the southeast
(Figure 5.36). This is also evident from the Wreckhouse wind study (Sutherland, 1963)
that found 20 percent of the Wreckhouse windstorms occurred when low pressure
systems tracked southeast of the Cabot Strait and 80 percent when they travelled to the
west or northwest.
93
Figure 5.30
Yearly Distribution of Wreckhouse Events at St. Andrew's
Maximum Mean Wind Speed >= 75 km/h
0
2
4
6
8
10
12
14
161
95
3
19
54
19
55
19
56
19
57
19
58
19
59
19
60
19
61
19
62
19
63
19
64
19
65
19
66
Year
#E
ve
nts Duration <3 hrs
Duration >=3 hrs
Figure 5.31
Monthly Distribution of Wreckhouse Events 1953-1966 at
St. Andrew's Maximum Mean Wind Speed >=75 km/h
0
5
10
15
20
25
Ja
n
Fe
b
Ma
r
Ap
r
Ma
y
Jun
e
Ju
ly
Au
g
Se
pt
Oct
Nov
De
c
Month
# E
ve
nts
94
Figure 5.32
Total # Observations at St. Andrew's
1953-1966
0
2000
4000
6000
8000
10000
195
3
195
4
195
5
195
6
195
7
195
8
195
9
196
0
196
1
196
2
196
3
196
4
196
5
196
6
Year
Figure 5.33
0
5
10
15
20
25
30
35
2000 2001 2002 2003 2004
Year
#E
ve
nts
< 3 hrs
>= 3 hrs
Yearly Distribution of Wreckhouse Events at
Wreckhouse 2000-2004
Maximum Mean Wind Speed >= 75 km/h
95
Figure 5.34
Monthly Distribution of Wreckhouse Events at
Wreckhouse 2000-2004
0
5
10
15
20
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
# E
ven
ts
Figure 5.35
Total # Observations at Wreckhouse 2000-2004
7200
7400
7600
7800
8000
8200
8400
8600
8800
9000
2000 2001 2002 2003 2004
Year
96
Figure 5.36 Wreckhouse Wind Event Storm Tracks
Tables 5.6A and 5.6B highlight the significance of the Wreckhouse winds in the
Codroy Valley. All maximum annual average wind speeds (all directions), at St.
Andrew’s and Wreckhouse, occurred during Wreckhouse wind events.
Table 5.6A.
Maximum Annual Average Wind Speed
St. Andrew’s, NL 1953-1966
YEAR
Wind Speed (km/h)
(1 Hour Average)
Direction
1953 140o@ 97
1954 140o@ 97
1955 140o@ 100
1956 160o@ 105
1957 110o@ 129
1958 160o@ 116
1959 140o@ 145
1960 180o@ 121
1961 110o@ 145
1962 140o@ 97
1963 140o@ 129
1964 140o@ 126
1965 110o@ 113
1966 Jan-May 110o@ 89
97
Table 5.6B.
Maximum Annual Average Wind Speed
Wreckhouse, NL 2000-2005
YEAR
Wind Speed (km/h)
(1 Hour Average)
Direction
2000 100o@ 128
2001 110o@ 120
2002 120o@ 120
2003 130o@ 126
2004 090o@ 122
2005 100o@ 110
5.7 AES40 Model data
Figures 5.37 and 5.38 show the annual average and maximum wind speeds,
respectively, for the AES40 data point. The results of the statistical analysis are presented
in table 5.7. There is a statistically increasing trend for the average yearly wind over the
period 1955 to 2002. When the 1967 to 2002 time period, roughly the same time that the
data from the observation network is being considered, the statistical significance is lost
and the trend resembles the one in the Stephenville Airport dataset.
Table 5.7.
AES40 Trend
(kph/Year)
N p-value **
Yearly Average (1955-2002) +0.028 48 0.032
Yearly Maximum (1955-2002) +0.106 48 0.080
Yearly Average (1967-2002) +0.007 36 0.733
Yearly Maximum (1967-2002) -0.004 36 0.859
** Significant at 5% level. Figure 5.39 shows the mean daily maximum wind for winter (DJF) and (figure 10.6)
shows the annual frequency of gale force or greater winds. The analysis is given in Table
5.7A. Figures 5.40 and 5.41 show box plots of winter daily maximum winds and monthly
maximum winds, respectively. The lack of statistical significance shown in Table 5.7A
98
Figure 5.37
AES 40 Yearly Average Wind Speed
0
5
10
15
20
25
30
35
40
1950 1960 1970 1980 1990 2000 2010
Year
Kp
h
Figure 5.38
AES 40 Yearly Maximum Wind Speed
0
20
40
60
80
100
120
140
1950 1960 1970 1980 1990 2000 2010
Year
Kp
h
99
Figure 5.39
AES 40 Mean Winter Daily Max Wind
30
35
40
45
50
55
1950 1960 1970 1980 1990 2000 2010
Year
kp
h
Figure 5.40
Year
Daily Max (kph)
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
1956
1955
100
80
60
40
20
0
AES40 Winter Daily Max Winds
100
Figure 5.41
Year
Monthly Max W
ind Speed
2002/03
2000/01
1998/99
1996/97
1994/95
1992/93
1990/91
1988/89
1986/87
1984/85
1982/83
1980/81
1978/79
1976/77
1974/75
1972/73
1970/71
1968/69
1966/67
1964/65
1962/63
1960/61
1958/59
1956/57
1954/55
100
90
80
70
60
50
40
30
Monthly Max Winds
Figure 5.42
AES 40 Count of > 34 Kts(1954 & 2003 removed)
0
10
20
30
40
50
1950 1960 1970 1980 1990 2000 2010
Year
Co
un
t
can also be seen in these plots with considerable interannual variability but no clear trend
is evident.
101
Table 5.7a.
AES40 Wind
Trends
Trend
(+/-)
N p-value **
Mean Winter (DJF) Maximum Wind
+ 48 0.294
Annual Frequency of Wind >= 34 knots
+ 48 0.227
AES40 yearly wind speeds were sorted into marine wind categories for a calendar year.
The results are presented in Figure 5.43 and the statistical analysis is presented in table
5.8. All significance tests were conducted at the 5% significance level.
Figure 5.43
AES40 Annual Wind Speed Categories
0.1
1
10
100
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
Year
Perc
en
tag
e
%<strong
% strong
%gale
Table 5.8.
Wind Category
1955-2002
Trend
(kph/Year)
N p-value **
< Strong (19 knots) -0.080 48 0.032
Strong (19 to 33 knots) +0.080 48 0.029
>= Gale (34 knots) +0.006 48 0.380
** Significant at 5% level.
102
The result for the strong category indicates a statistically significant increasing
trend while the less than strong category has a statistically significant decreasing trend.
The p-values for these regression lines were 0.029 and 0.032 respectively. The increasing
trend for the gale force or greater category is not statistically significant at the 5% level.
This analysis indicates an overall decrease in weaker winds but it does not translate into
an increased frequency of more extreme winds.
An analysis of the AES40 wave data set for the Cabot Strait is presented in
Figures 5.44 and 5.45. The results are summarized in Table 5.9.
Figure 5.44
Yearly Peak Sig and Max Wave Height
(1954 & 2003 removed)
0
5
10
15
20
1950 1960 1970 1980 1990 2000 2010
Year
He
igh
t (m
)
Sig Wave
Max Wave
Figure 5.45
Yearly Count of Wave >= 4 m(1954 $ 2003 removed)
0
10
20
30
40
50
60
70
1950 1960 1970 1980 1990 2000 2010
Year
Co
un
t
103
Table 5.9.
Yearly AES40 wave
value 1955-2002
TREND
cm/yr
N p-value **
Peak Maximum wave height
+0.070 48 0.002
Peak Significant wave height
+0.035 48 0.005
Count of Waves >= 4 metres
0.00 48 0.850
** Significant at 5% level. The result for the peak yearly maximum and significant wave height categories
indicate a statistically significant increasing trend. The annual count of significant wave
heights greater than 4 metres show no trend that is not statistically significant.
5.8 Environment Canada 100 Year (1901 - 2000) Tropical Cyclone Climatology
Few meteorological phenomena capture the attention of meteorologists, the media
and the general public as hurricanes do. Images of these storms charting their way
through the Gulf of Mexico causing the evacuation of millions of people have a way of
leaving an impression. Eventually many of these storms make their way to Atlantic
Canada near south-western Newfoundland (Figure 5.46) where they can take many
forms. The most common scenarios for a tropical cyclone that passes through Atlantic
Canada is to weaken as it crosses eastern North America or weaken over the cold waters
of the North Atlantic. In these cases the winds will diminish considerably below
hurricane strength and the widespread torrential rain will diminish to areas of heavy
showers. Hurricane Ophelia (2005) is a good example.
However there are scenarios when these storms maintain their strength and make
landfall as full-fledged hurricanes or interact with processes in the upper atmosphere that
will cause intensification. These storms are accompanied by torrential rains, hurricane
force winds and damaging waves and storm surge. In October 2000 hurricane Michael
made landfall on the south coast of Newfoundland as a category one hurricane.
104
Figure 5.46 Tropical cyclone tracks
Environment Canada has analyzed 100 years of tropical cyclone tracks as they pass
through Atlantic Canada and recorded when these storms pass within 260 kilometres of
33 different locations. We have decided to use the criteria of a tropical cyclone passing
within 260 kilometres of Sydney or Port aux Basques to determine when a tropical
cyclone might impact travel through the Cabot Strait or southwestern Newfoundland. The
results are shown in Figures 5.47 and 5.48. Figure 5.47 shows the monthly frequency
distribution of tropical cyclone activity with September being the most active month.
Figure 5.48 shows the annual frequency of tropical cyclone activity over 100 years. An
active year consists of 3 storms and many years in which no storms pass within 260 km
of the Cabot Strait area. There is no obvious trend in tropical cyclone activity over the
study area.
105
Figure 5.47
Figure 5.48
Tropical Cyclone Frequency by Year
Port-aux Basques and Sydney
260 km radius
1901-2000
0.00
1.00
2.00
3.00
4.00
19
01
19
03
19
05
19
07
19
09
19
11
19
13
19
15
19
17
19
19
19
21
19
23
19
25
19
27
19
29
19
31
19
33
19
35
19
37
19
39
19
41
19
43
19
45
19
47
19
49
19
51
19
53
19
55
19
57
19
59
19
61
19
63
19
65
19
67
19
69
19
71
19
73
19
75
19
77
19
79
19
81
19
83
19
85
19
87
19
89
19
91
19
93
19
95
19
97
19
99
5.9 Discussion: Inhomogeneous Data
In order to draw as much trend information from the data as possible the
inhomogeneities in the data, documented and perhaps otherwise, need to be considered.
To determine if a change in wind speed is related to changes in the physical environment
or changes in the observation history it is helpful to determine when the wind speed
changed. If the change corresponds with an observation method or location change it
raises the possibility that the increase or decrease in wind speed is not entirely natural but
Tropical Cyclone Frequency by Month
Port-aux-Basques and Sydney
260 km radius
1901-2000
0
10
20
30
Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec
106
caused by the non-homogeneous nature of the measurements. A double mass curve is an
arithmetic plot of the accumulated values of observations of two variables that are paired
in time and thought to be related. As long as the relationship remains constant the double-
mass curve will appear as a straight line; a deviation denotes the timing of a change1. The
annual percentages of strong winds for our observation sites where inhomogeneities exist
are compared to the annual percentages of strong winds AES40 data set where
inhomogeneities do not exist. Results are displayed in Figures 5.49 to 5.53.
Figure 5.49 shows the accumulated annual percentages of strong winds for all 4
sites plus the AES40 site. Note the relative consistent slope of the AES40 data when
compared to the historical climatological data.
Figure 5.50, Burgeo indicates changes in 1975, 1979, 1985 and 1993. However
none of these inflexion points correspond to dates of change in the site history.
Figure 5.51, Port aux Basques indicates changes in 1972, 1980, 1984, 1992 and
1997. There were changes to site history in 1983, 1991 and 1998.
Figure 5.52, Sydney indicates changes in 1971, 1978, 1982, 1989 and 1993 and
possible more.
Figure 5.53, Stephenville indicates slight changes in 1974, 1988, 1994 and 1996.
None of these inflexion points correspond to dates of changes as indicated by the
inspector reports.
From the analysis of the double mass curve it appears the wind data observed at
Stephenville has the highest probability of being the least affected by the documented
inhomogeneities in its observational history. The changes present in its curve do not
correspond to the documented changes in observing method or location. The observations
at Burgeo also have a high probability of not being affected by the documented changes
in observing method but there seems to be a significant and persistent reduction in the
percentage of strong winds beginning in the mid 1980s. This could be a natural reduction
in the local winds or the result of changes in the physical environment that are not
documented in the inspector’s reports. The changes in the Port aux Basques curve
correspond to changes in observing method. Changes in Sydney’s curve are so dramatic it
1 http://amsglossary.allenpress.com/glossary
107
Figure 5.49
Accumulated % Strong Winds VS. Year
0
100
200
300
400
500
600
700
800
900
1000
1960 1970 1980 1990 2000 2010Year
%
AES40
YJT
WBF
WZB
YQY
Figure 5.50
Double Mass Curve:% Strong Winds
WBF VS. AES 40
0
100
200
300
400
500
600
700
800
0 200 400 600 800 1000
108
Figure 5.51
Double Mass Curve:% Strong Winds
WZB VS. AES 40
0
100
200
300
400
500
600
700
0 200 400 600 800 1000
Figure 5.52
Double Mass Curve:% Strong Winds
YQY VS. AES 40
0
50
100
150
200
250
300
0 200 400 600 800 1000
Figure 5.53
Double Mass Curve:% Strong Winds
YJT VS. AES 40
0
50
100
150
200
250
300
0 200 400 600 800 1000
109
is hard to imagine such changes occurring naturally in such a short period of time.
Accordingly the Stephenville and Burgeo historical data will be given the greatest weight
when determining the presence of long term trends.
5.9 Summary of Overall Trends
Our analysis of the wind regime for southwestern Newfoundland and the Cabot
Strait included an analysis of historical and model derived climatological data, model
derived wave statistics and data presented in Environment Canada's 100 year tropical
cyclone climatology for the last 35 to 50 years. A considerable portion of our analysis
indicates that there is no trend in extreme wind events for the area.
5.9.1 WBF, YJT and AES40 wind data
The climatology of historical wind data from Stephenville and Burgeo and the AES40
model derived climatological data presented does not indicate a clear trend in the
historical mean or extreme wind conditions of southwest Newfoundland and the Cabot
Strait.
• The yearly average wind observed at Burgeo has a statistically significant
decreasing trend. However, between 1986 and 1990 the annual percentage of
strong winds significantly decreases and there is an equally dramatic increase in
the percentage of less than strong winds. It appears that a significant and
permanent inhomogeneity may have been introduced into the data during that
period that has not been documented.
• The increasing trend in the maximum yearly wind at Burgeo is not statistically
significant.
• Stephenville’s trends are increasing for yearly average and maximum winds but
they are not statistically significant at the 95% confidence level.
• The AES40 data has a statistically significant increasing trend in yearly average
winds. However the increasing trend in maximum winds is not statistically
110
significant at the 95% confidence level when considering the entire data set.
When the data pre-1966 is removed, i.e. the time period being analyzed is the
same as Stephenville and Burgeo, the statistical significance is lost and the overall
trend is similar to Stephenville’s.
• When the duration and intensity of individual wind events for Burgeo and
Stephenville are considered, by analyzing the TII, the trends emulate the trends in
the mean winds. Burgeo’s TII decreasing over time and Stephenville with no
significant trend. However, when the 2 extreme years are removed from the early
period of Burgeo’s time series for comparison, the statistical significance is lost
and it gives the same answer as the Stephenville TII analysis.
5.9.2 AES40 wave data
The results for the wave data emulate the wind data such that the maximum data, yearly
peak maximum wave height and the annual count of significant wave heights greater than
4 metres are not statistically significant. However the mean annual significant wave
height, like the mean average wind, does show a slight, statistically significant, increasing
trend
5.9.3 Wreckhouse data
The data show considerable inter-annual and inter-decadal variability in the frequency of
Wreckhouse events and the maximum sustained wind expected. However, there are no
long term trends present in the data.
5.9.4 100 year tropical storm climatology data
There has been no clear scientifically determined consensus that tropical cyclones are
increasing in frequency or intensity. Active and in-active periods for tropical cyclones in
the Atlantic basin last between 25 and 40 years each and it is possible that we are 10
years into an active cycle (Chris Landsea, http://www.aoml.noaa.gov/hrd/tcfaq/G4.html).
111
The data for the Cabot Strait area that has been analyzed confirms the large inter-annual
and inter-decadal variability in tropical storm frequency with no clear long term trend
present.
5.11 Acknowledgements
We would like to acknowledge the following people who greatly aided in the preparation
of this report:
• Gerard Morin and Rick Fleetwood of the Atlantic Climate Centre in Fredericton,
New Brunswick.
• Neil Burgess, Canadian Wildlife Service
• Jack Cossar, Brian Hulan, Andre Dwyer and Gerry Rockwood of the
Environmental Monitoring Division, Atlantic Region.
• Jerry Pulchan, Environmental Protection
• Dr. Leonard Lye, Memorial University of Newfoundland.
• Doug Mercer, George Parkes, Ming Szeto, Bruce Whiffen and Bridget Thomas of
Environment Canada, Atlantic Region.
• Peter Bowyer, Canadian Hurricane Centre
• Kevin Pike, Environmental Protection
112
6. The Value of Economic Loss Associated with Weather-Related Delays on the
North Sydney-Port aux Basques Marine Transportation Link in 2003 and 2004
Wade Locke
6.1 Introduction
This report was prepared as part of the study entitled: Storm and Wind Impacts on
Transportation, Southwest Newfoundland. The purpose of this report is to estimate the
economic loss associated with weather-related delays associated with Marine Atlantic’s
marine transportation service between North Sydney, Nova Scotia and Port aux Basques,
Newfoundland and Labrador.
The economic costs associated with weather related delays on the North Sydney-Port aux
Basques run averaged $3.5 million per year. The estimates for each year were:
• $2.1 million in 2003; and
• $4.9 million in 2004
6.2 Methodology and Results
There are no published data available on the number and duration of weather-related
delays or on the number of passengers or commercial vehicles affected by these delays
for the marine transportation link between North Sydney, Nova Scotia and Port aux
Basques, Newfoundland and Labrador. However, Marine Atlantic records a daily
Situation Report for the ships that it operates on this run.2 For the purpose of this study,
Marine Atlantic provided the 2003 and 2004 Situation Reports for both the Port aux
Basques and North Sydney ports. This meant that 1,462 reports were reviewed and
analyzed for this study3.
2 The four ships that provided marine transportation services between Port aux Basques and North Sydney between 2003 and 2004 were: the MV Caribou, the MV Joseph and Clara Smallwood, the MV Leif Ericson and the MV Atlantic Freighter. 3 All data are available from Norm Catto on request.
113
These reports indicated for each day of the year and for all of the ships involved in this
route the following information:
• the number of passengers;
• the number of passenger-related vehicles;
• the number of commercial vehicles;
• the time of departure and the time of arrival; and
• whether the ship was late leaving or arriving and the reason why, including
specifying weather-related delays.
For each of the ships operating on the Nova Scotia/Newfoundland and Labrador run, it is
possible to determine the number of weather-related delays and their duration. In
addition, it is possible to determine the number of passengers and commercial traffic that
was affected by these delays. Because of the normal variation in sailing times, only
delays of two hours or more are included in this analysis.
For each weather-related delay of two hour or more, the corresponding number of
passengers and commercial vehicles are recorded. As well for each delay, the number of
passenger hours are calculated as the product of the number of passengers and the
number of hours involved in that specific delay. Similarly, the number of commercial
vehicle hours is calculated as the product of the number of commercial vehicles involved
in the delay times the number of hours associated with the delay. This information is
presented in Table 6.1.
114
Table 6.1: Weather Related Delays on the North Sydney-Port aux Basques Run
for Marine Atlantic in 2003 and 2004
Ship Delay Hours
Passengers Commercial
Vehicles Passengers
Hours
Commercial Vehicles
Hours
Year - 2003
Caribou 168 2,414 918 25,388 9,706
Smallwood 257 2,266 730 35,733 14,303
Atlantic Freighter 3 6 61 18 183
Leif Ericson 232 1,881 946 22,298 12,099
Combined 660 6,567 2,655 83,437 36,291
Year - 2004
Caribou 417 4,061 1,251 83,665 22,244
Smallwood 461 4,185 1,724 70,177 25,806
Atlantic Freighter 150 60 421 1,106 7,072
Leif Ericson 349 2,300 862 50,818 18,955
Combined 1,377 10,606 4,258 205,766 74,077
Average – 2003 and 2004
Caribou 292 3,238 1,085 54,526 15,975
Smallwood 359 3,226 1,227 52,955 20,055
Atlantic Freighter 77 33 241 562 3,628
Leif Ericson 291 2,091 904 36,558 15,527
Combined 1,018 8,587 3,457 144,601 55,184
The next step involved trying to assign a value to the lost time associated with these
weather-related delays. In this analysis, it is assumed that the economic value of a
specific unit of time saved from transportation projects is equivalent to, but of opposite
sign, for the same-sized unit of time lost due to weather-related delays.
Transport Canada, in their Guide to Benefit-Cost Analysis4 suggests using $24.00 per
hour in 1990 dollars for the value of business travel by automobile saved from
transportation projects in Canada and using $9.10 per hour in 1990 dollars where
“reliable information on trip purpose (i.e., business/non-business) is not available.” Since
there is no data on which of the passengers are traveling for business or other purposes,
the $9.10 per is used to value the lost time for passengers caused by the weather delay.
The lost time associated with commercial vehicles is valued at $24.00 per hour. In order
to take into account the level of inflation that has occurred between 1990 and 2003 and
4 See http://www.tc.gc.ca/Finance/BCA/en/Section7.htm.
115
2004, these dollar estimates are adjusted to their 2003 and 2004 equivalents utilizing the
Consumer Price Index for Canada (1992=100).5 Making these adjustments yields:
• $11.93 per hour for passengers and $31.46 for commercial vehicles in 2003; and
• $12.15 per hour for passengers and $32.05 for commercial vehicles in 2005.
Applying these values to the weather-related delays generates the economic value of the
lost time on the North Sydney-Port aux Basques run as a result of weather in 2003 and
2004. These estimates are presented in the following table.
Table 6.2: Value of Weather Related Delays on the North Sydney-Port aux Basques
Run for Marine Atlantic in 2003 and 2004
Ship Passengers
Hours
Commercial Vehicles
Hours
Dollar Value of
Passengers Delays
Dollar Value of
Commercial Vehicles Delays
Total Value of Weather Delays
Year – 2003
Caribou 25,388 9,706 $302,879 $305,351 $608,230
Smallwood 35,733 14,303 $426,295 $449,972 $876,267
Atlantic Freighter 18 183 $215 $5,757 $5,972
Leif Ericson 22,298 12,099 $266,015 $380,635 $646,650
Combined 83,437 36,291 $995,403 $1,141,715 $2,137,118
Year –2004
Caribou 83,665 22,244 $1,016,524 $712,904 $1,729,428
Smallwood 70,177 25,806 $852,651 $827,082 $1,679,733
Atlantic Freighter 1,106 7,072 $13,438 $226,658 $240,096
Leif Ericson 50,818 18,955 $617,439 $607,508 $1,224,946
Combined 205,766 74,077 $2,500,051 $2,374,152 $4,874,203
Average – 2003 and 2004
Caribou 54,526 15,975 $659,701 $509,127 $1,168,829
Smallwood 52,955 20,055 $639,473 $638,527 $1,278,000
Atlantic Freighter 562 3,628 $6,826 $116,207 $123,034
Leif Ericson 36,558 15,527 $441,727 $494,071 $935,798
Combined 144,601 55,184 $1,747,727 $1,757,933 $3,505,660
5 The CPI (1992=100) was 93.3 in 1990, 122.3 in 2003 and 124.6 in 2004.
116
6.3 Conclusion
Weather-related delays on the North Sydney-Port aux Basques run had an average
economic loss of $3.5 million per year. The corresponding losses for 2003 and 2004
were $2.1 million and $4.9 million, respectively. These weather-related delays involved
6,567 passengers and 2,655 commercial vehicles in 2003. Weather-related delays were
more frequent in 2004 than in 2003. Specifically, in 2004 there were 10,606 passengers
and 4,258 commercial vehicles that experienced delays on the Port aux Basques-North
Sydney run. Moreover, the number of hours of weather related delays in 2004 were
nearly double those of 2003: 1,377 hours in 2004 versus 660 hours in 2003.
117
7. Summary and Discussion
The southwest coast of Newfoundland has been subjected to many significant
storms resulting in property destruction. The storm of January 2000 is the most recent
event causing significant damage to Channel-Port aux Basques. Analysis of this event
has served as a model for predicting the impact of future storms. The coastline of
southwestern Newfoundland has been subject to at least 5 storm surge events since
January 2000, including those resulting from Hurricane Gustav (12 September 2002) and
Hurricane Frances (2 September 2004).
The estimated economic damage from the January 2000 event exceeded $1
million. However, study of other flooding events in Newfoundland indicates that actual
costs were more than twice the reported figures in all instances. Applying a similar
standard to Port aux Basques would suggest that the actual financial impact of the 21-22
January 2000 storm surge event would approach $ 3 million. This figure does not
account for any losses resulting in disruption to transportation between Port aux Basques
and the remainder of Newfoundland.
The effectiveness of any particular storm at a location depends upon the angle of
wave attack, the number of previous events during the season, and other local factors.
Adjacent beaches can exhibit very different responses to a particular storm, as was
evident on southwestern Newfoundland beaches impacted by Hurricanes Gustav (2002)
and Frances (2004).
Although the relationship between changes in hurricane frequency and magnitude,
and increases in air temperature or sea surface temperature, is not clear at present, and
consensus does not exist, it is apparent that the North Atlantic is currently undergoing a
period of increased hurricane activity. Planning emergency response measures to cope
with the impact of storm surges associated with either hurricanes or mid-latitude cyclones
is necessary. Exercises such as “Operation Dolphin”, conducted at Channel- Port aux
Basques in June 2006 (Seguin et al., 2006) are vital planning and preparatory tools.
Tsunamis are the products of seismic activity, and are not related to climate.
However, their potential impact on the southwest Newfoundland coastline is similar to
that for storm surges. The frequency of tsunami events cannot be assessed at present.
118
Sea level is currently rising at Port aux Basques at ca. 3.3 mm/a. Rising sea level
will allow successive storm surges to rise higher and penetrate further inland. The
shoreline at Port aux Basques Harbour is not sensitive to coastal erosion resulting from
sea level rise. Coastal erosion is occurring along dune-backed sandy shorelines, such as
those at JT Cheeseman and Sandbanks Provincial Parks.
There is no clear net change in tidal regime for the period of tidal records for Port
aux Basques (1935-present). There is, however, an indication of the de-tided residual
increasing over time (approximately 10 cm from 1959 to 2005). Unfortunately, this
increase cannot be accurately interpreted since the data set is highly fragmented, but
some of the increasing trend is likely due to relative sea level rise in the area.
There is a clear seasonal trend in mean water level. The mean and variance is
higher during the fall and winter than in the spring and summer. The atmospheric
pressure exhibits a clear seasonal trend. The pressure is lower with a higher variability
during the late fall and winter.
There is no obvious correlation between the NAO and the tidal constituents, or
storm surge activity (neither by frequency in terms of number of events or duration nor
by maximum surge height). In contrast to the situation in eastern Newfoundland,
considering the North Atlantic Oscillation is not an effective predictor or explanation for
surge activity at Port aux Basques. The annual number of events that exceed 60 cm shows
no real trend and there has been little change in the annual maximum storm surge
elevation.
The maximum water level for extreme events, such as the January 2000 storm,
that have been excluded from the data record can be roughly estimated using basic
statistical correlations based on the recorded meteorological conditions along with the
records of other previous storm/surge events. However, the lack of tide gauge data from
the period surrounding the January 2000 storm represents a serious limitation on
interpretation of this event, and on the ability to recognize long-term trends and predict
the pattern of future storm surge events. Tidal gauge networks require adequate
maintenance and associated funding, in order for significant and productive research to
continue and for public safety.
119
Historically, Wreckhouse Events have been known and respected since the initial
railway construction period. At present, it is not possible to assess if any change has
occurred in the frequency of Wreckhouse Events, as judged from resultant delays to
transportation, over the historical record. The available archival data appears to be
inadequate for such an assessment.
The data show considerable inter-annual and inter-decadal variability in the
frequency of Wreckhouse events and the maximum sustained wind expected.
Differences in analysis and treatment of the same set of meteorological data can produce
seemingly different results. The variations in results reflect the relatively short length of
the data set available, and the difficulties in assessing the data.
Figures 7.1 and 7.2 illustrate data generated during preliminary analysis, and
presented in 2005. The data include the percentage of Wreckhouse winds in excess of 57
km/h, a critical value for the interruption of transportation (Figure 7.1), and the inferred
peak velocity for Wreckhouse winds (Figure 7.2). Both data sets suggest a trend of
increasing Wreckhouse events, based on analysis of data from ca. 1967 to 2004.
Figure 7.1 Percentage of Wreckhouse easterly winds in excess of 57 km/h. Graph
prepared by Dale Foote and Dermot Kearney from Environment Canada data, 2005.
% of WZB easterly winds >= 57 kph
0
5
10
15
20
25
30
1960 1970 1980 1990 2000 2010
Year
%
120
Figure 7.2 Inferred yearly peak Wreckhouse wind velocities, based on data from
ca. 1967 to 2004. Graph prepared by Dale Foote and Dermot Kearney from Environment
Canada data, 2005.
However, subsequent analysis, reported in chapter 5 of this report and including
data from 2005, suggests that the activity of Wreckhouse winds may be much more
variable. Figures 7.3 and 7.4 suggest that there is no apparent long-term trend in the
Wreckhouse wind data, with peak wind velocities (Figure 7.3) and total yearly hours
(Figure 7.4)
Inferred yearly Wreckhouse Peak wind
80
90
100
110
120
130
140
1960 1970 1980 1990 2000 2010
Year
2 m
inu
te P
eak w
ind
(kp
h)
121
C4
xwr wind
2002-04
1999-01
1996-98
1993-95
1990-92
1987-89
1984-86
1981-83
1978-80
1975-77
1972-74
1969-71
1966-68
140
130
120
110
100
90
80
Inferred Wreckhouse Peak Wind
Figure 7.3 Inferred Wreckhouse Peak wind velocities, three year averages, 1966-2004.
Wreckhouse Event Total Yearly Hours (1966, 1997 &1998 Removed)
0
100
200
300
400
500
1960 1970 1980 1990 2000 2010
Year
Ho
urs
Figure 7.4 Wreckhouse Event total yearly hours
122
The available data thus are subject to different interpretations. The increased wind
velocities documented at Port aux Basques, as discussed in chapter 5, indicate that wind
velocities at Wreckhouse would also increase, as these two phenomena are linked
meteorologically. However, increases in mean wind velocity at Port aux Basques may
not translate directly into increases in peak wind velocity at Wreckhouse.
At present, it is prudent to conclude that Wreckhouse events will not become less
frequent in the future, and could become more frequent. The problems of data analysis
also strongly indicate that more detailed, locally specific investigations are necessary.
They further highlight the absence of reliable (or any) archival data, which could be used
to assess a longer-term change in the number and severity of events (replacing a 40-year
recording period, with gaps, with a longer time series). The problem is similar to the
difficulties in interpreting the tidal and storm surge record, which is also relatively short
and contains significant gaps.
Assessment of climate change and variation is contingent on reliable, complete data
recorded over long periods of time. Unfortunately, missing data severely hinders
interpretation of climate patterns for both Port aux Basques and Wreckhouse.
The most recent cost estimates of disruption to highway traffic, summarized by
ADI Limited (1994), suggest that accidents cost ca. $236,000 annually, and delays cost a
further $1.9 million (as measured in 2006 dollars). Thus, the cost of Wreckhouse Events
to the provincial economy is in excess of $ 2.1 million annually. This figure only
includes insured losses and delays, and does not include delays or damage to smaller,
non-commercial vehicles, or costs involved with response to accidents or road
maintenance and repair.
Analysis of trends of mean wind speed indicate a statistically significant increasing
trend at Port aux Basques, combined with statistically significant decreasing trends for
Burgeo and Sydney Airport. These differences reflect the influence of local topography
on wind velocity. They also indicate a necessity for detailed local measurements at
several sites, in order both to establish long-term regional trends and for local forecasting
in aid of marine navigation.
123
There is high interannual variability in westerly wind disruption to marine
transportation. Although easterly winds are of concern for the Wreckhouse area, it is the
westerlies that have the greatest potential to produce stormy conditions in Cabot Strait.
Weather-related delays on the North Sydney-Port aux Basques run had an average
economic loss of $3.5 million per year. The corresponding losses for 2003 and 2004
were $2.1 million and $4.9 million, respectively. These weather-related delays involved
6,567 passengers and 2,655 commercial vehicles in 2003. Weather-related delays were
more frequent in 2004 than in 2003. Specifically, in 2004 there were 10,606 passengers
and 4,258 commercial vehicles that experienced delays on the Port aux Basques-North
Sydney run. Moreover, the number of hours of weather related delays in 2004 were
nearly double those of 2003: 1,377 hours in 2004 versus 660 hours in 2003.
Adding the costs for transportation delays related to storm and wind activity along
the route from Channel- Port aux Basques through Wreckhouse suggests an average loss
of $ 5.6 million annually. These costs represent the current losses due to storms, surges,
and winds, and do not consider the potential of increased future losses due either to
changes in the condition of the infrastructure or to any changes in climate. The available
data suggest that the climate regime, as it currently exists, is sufficient to have significant
economic impact to transportation in Southwestern Newfoundland.
124
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134
9. Appendices
Appendix A
Station Histories STEPHENVILLE - 48 32’/58 33’
DATE
ANEMOMETER ELEVATION/
HEIGHT
ANEMOMETER TYPE
WIND RECORDER TYPE
MANNED/ AUTO
WIND SPEED AVERAGING
PERIOD (MINUTES)
Jan/53 Unknown/ 3.96m AN-GMQ-11 UNKNOWN MANNED ? June/66 7.92m/ 6m U2A MONRO MANNED 1 Sept/66 7.92m/ 10.0m U2A MONRO MANNED 1 ?/1980 7.92m/ 10.0m 78D ELECTRONIC MANNED 2
BURGEO- 47 37’/57 37’
DATE
ANEMOMETER ELEVATION/
HEIGHT
ANEMOMETER TYPE
WIND RECORDER TYPE
MANNED/ AUTO
WIND SPEED AVERAGING
PERIOD (MINUTES)
July/66 22.73m/ 10.0m 45B WIND RUN MANNED 60 Sept/69 22.73m/ 10.0m U2A MONRO MANNED 10
Oct 02/91 22.73m/ 10.0m U2A MONRO MANNED and AUTO8
10
July 31/95 22.73m/ 10.0m U2A N/A AUTO8 10
SYDNEY - 46 10’/60 03’
DATE
ANEMOMETER ELEVATION/
HEIGHT
ANEMOMETER TYPE
WIND RECORDER TYPE
MANNED/ AUTO
WIND SPEED AVERAGING
PERIOD (MINUTES)
June/53 55.5m/ 19.5m 45B WIND RUN MANNED 60 August/55 55.5m/ 19.8m 45B WIND RUN MANNED 60
November/59 55.5m/ 19.5m U2A MONRO MANNED ? February/65 55.5m/ 16.4m 45B WIND RUN MANNED 60
July/66 55.5m/ 10.0m U2A MONRO MANNED 1 August/68 55.5m/ 10.0m U2A MONRO MANNED 1 June/72 55.5m/ 10.0m U2A/R MONRO MANNED 1 ?/1980 55.5m/ 10.0m U2A/R MONRO MANNED 2
November/96 55.5m/ 10.0m 78D ELECTRONIC MANNED 2
135
PORT AUX BASQUES
SITE DESCRIPTION
DATE
ANEMOMETER ELEVATION/
HEIGHT
ANEMOMETER TYPE
WIND DISPLAY
WIND SPEED AVERAGING
PERIOD (MINUTES)
Telegraph and Cable Office
1929
45.5m/ 6.1m
?
?
?
Loran Transmitting Station
1955
N/A
N/A
N/A
N/A Mouse Island 47 34’/ 59 10’
June/66 17.0m/ 13m U2A MONRO 10
800m NNE of previous location
August/83 49m/ 10m U2A DIAL 10
Manned/Auto (no change in
location)
October/91 49m/ 10m U2A DIAL 10
AWOS (no change in
location)
Spring/98 49m/ 10m 78D ELECTRONIC 10
ST. ANDREWS-47 46’ /59 19
’
DATE
ANEMOMETER ELEVATION/
HEIGHT
ANEMOMETER TYPE
WIND RECORDER TYPE
MANNED/ AUTO
WIND SPEED AVERAGING
PERIOD (MINUTES)
1953-May 1966 21.0/1.83m 45B NONE MANNED 60
WRECKHOUSE-47 42’ / 59 18
’
DATE
ANEMOMETER ELEVATION/
HEIGHT
ANEMOMETER TYPE
WIND RECORDER TYPE
MANNED/ AUTO
WIND SPEED AVERAGING
PERIOD (MINUTES)
Jan 2000 31.7 m/10m R.M Young NONE AUTO 2
136
Appendix B: Seasonal Graphs
Burgeo Seasonal Wind Speed Categories
DJF 1970-2004
0.01
0.1
1
10
1001
97
0
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Burgeo Seasonal Wind Speed Categories
MAM 1970-2004
0.01
0.1
1
10
100
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
137
Burgeo Seasonal Wind Speed Categories
JJA 1970-2004
0.01
0.1
1
10
100
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Burgeo Seasonal Wind Speed Categories
SON 1970-2004
0.01
0.1
1
10
100
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
138
Port aux Basques Seasonal Wind Speed Categories
DJF 1967-2004 (1998 removed)
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Port aux Basques Seasonal Wind Speed Categories
MAM 1967-2004 (1998 removed)
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
139
Port aux Basques Seasonal Wind Speed Categories
JJA 1967-2004
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Port aux Basques Seasonal Wind Speed Categories
SON 1967-2004 (1997 removed)
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
140
Stephenville Airport Seasonal Wind Speed Categories
DJF 1967-2004
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Stephenville Airport Seasonal Wind Speed Categories
MAM 1967-2004
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
141
Stephenville Airport Seasonal Wind Speed Categories
JJA 1967-2004
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Stephenville Airport Seasonal Wind Speed Categories
SON 1967-2004
0.01
0.1
1
10
100
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
142
Sydney Airport Seasonal Wind Speed Categories
DJF 1969-2004
0.01
0.1
1
10
100
19
69
19
72
19
75
19
78
19
81
19
84
19
87
19
90
19
93
19
96
19
99
20
02
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
Sydney Airport Seasonal Wind Speed Categories
MAM 1969-2004
0.01
0.1
1
10
100
19
69
19
72
19
75
19
78
19
81
19
84
19
87
19
90
19
93
19
96
19
99
20
02
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
143
Sydney Airport Seasonal Wind Speed Categories
JJA 1969-2004
0.01
0.1
1
10
100
19
69
19
72
19
75
19
78
19
81
19
84
19
87
19
90
19
93
19
96
19
99
20
02
Year
% O
cc
urr
en
ce
% < 19
% Strong
% Gale
% Storm
144
Appendix C: Wind Rose Diagrams
Joint Frequency Distribution
Burgeo, NL (1966-2004) February
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.52
5.43 4.01
6.19
6.03
7.84
4.15
2.03
1.48 2.39
2.32
3.73
3.57
12.89
16.65
9.99 6.80
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) March
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
5.23
4.71 4.33
7.43
7.66
11.22
4.96
2.35
1.96 2.97
2.98
4.13
4.71
13.18
9.99
6.41
5.76
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) April
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
5.84
4.26 3.80
6.06
8.56
18.21
7.67
3.08
2.37 2.37
2.43
3.67
4.53
11.79
6.16
4.84
4.36
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
145
Joint Frequency Distribution
Burgeo, NL (1966-2004) May
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
7.58
2.72 2.39
4.51
7.04
21.20
11.06
3.54
2.65 2.28
2.31
4.89
5.18
11.00
4.61
3.77
3.28
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) June
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
9.19
2.15 1.51
2.31
4.48
23.78
12.02
4.34
2.85 2.40
2.73
5.79
6.00
11.05
4.12
3.12
2.17
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) July
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
11.37
1.39 1.19
1.63
4.11
24.49
11.30
4.60
3.27 2.65
2.69
5.54
7.08
10.72
4.05
2.33
1.60
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) August
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
12.19
1.93 1.54
2.34
5.03
16.12
7.05
3.44
3.14 4.08
4.34
6.77
7.85
12.53
5.54
3.57
2.54
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
146
Joint Frequency Distribution
Burgeo, NL (1966-2004) September
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
9.73
3.03 2.38
3.90
5.44
11.77
5.30
2.68
2.91 4.05
3.73
5.65
6.82
15.15
8.10
5.55
3.81
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) October
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
6.68
3.62 3.22
4.27
5.72
9.86
4.40
2.81
2.38 3.69
3.68
4.81
6.54
16.55
9.87
6.90
5.01
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) November
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.07
3.60 3.15
5.60
6.99
9.84
3.87
2.22
2.17 3.66
3.04
4.02
4.61
15.63
14.35
7.95
5.24
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
Joint Frequency Distribution
Burgeo, NL (1966-2004) December
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.56
5.07 3.99
5.46
6.02
7.72
3.84
2.34
2.02 3.21
2.67
3.25
4.58
14.79
16.28 8.69
6.48
Wind Speed ( Kilometers Per Hour)
1 11 21 31 41 51
147
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) January
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
1.37
4.21 3.16
3.28
5.40
8.17
2.69
2.32
2.33 3.63
3.26
2.77
5.54
15.61
16.03
14.38
5.86
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) February
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.35
4.61 3.18
2.96
6.34
10.09
3.39
2.03
1.72 3.03
2.71
2.28
4.21
17.28
16.56
12.49
4.78
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) March
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.98
4.58 2.93
3.44
7.20
17.55
4.41
2.16
2.06 3.20
1.90
1.60
3.50
14.16
14.00
10.05 4.30
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) April
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 10% intervals.Calms included at center.
2.77
4.41 2.77
2.55
6.89
28.52
5.48
2.27
1.57 1.90
1.40
1.23
2.68
11.11
13.82
7.15
3.50
Wind Speed ( kmh)
1 11 21 31 41 51
148
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) May
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 10% intervals.Calms included at center.
3.34
3.13 1.67
1.88
5.60
35.40
6.65
2.10
1.39 1.79
1.29
1.05
1.96
11.37
13.02
5.71
2.65
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) June
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 10% intervals.Calms included at center.
3.92
2.18 0.94
1.07
4.13
37.82
7.15
2.18
1.54 1.66
1.41
1.09
2.11
12.27
13.13
5.27
2.12
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) July
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 10% intervals.Calms included at center.
3.99
1.32 0.66
0.80
4.41
39.06
7.16
2.42
1.67 2.25
1.70
1.35
2.74
13.16
11.82
3.88
1.62
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) August
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
5.70
2.30 1.17
1.34
5.89
24.99
5.39
2.77
2.78 4.15
2.83
2.18
3.21
14.63
12.21
5.84
2.62
Wind Speed ( kmh)
1 11 21 31 41 51
149
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) September
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
5.04
4.13 1.80
1.99
5.66
17.76
4.54
2.76
2.76 4.05
2.78
2.22
3.03
13.44
15.08
8.82
4.14
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) October
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.12
4.62 2.34
2.12
5.87
15.22
3.60
2.47
2.65 3.97
2.97
2.71
3.96
15.44
13.69
10.02 5.21
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) November
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
1.98
4.65 2.86
2.87
5.75
13.56
3.42
2.28
2.59 3.98
3.01
2.50
3.95
14.64
14.30
11.93
5.73
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Port aux Basques, NL (1966-2004) December
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
1.75
5.24 3.29
3.35
6.48
9.95
3.29
2.22
2.29 3.49
2.83
2.53
4.47
13.92
15.64
13.14
6.12
Wind Speed ( kmh)
1 11 21 31 41 51
150
Joint Frequency Distribution
Stephenville A, NL (1967-2004) January
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.34
3.51 2.95
6.81
9.18
7.62
1.50
1.38
1.57 4.49
2.83
3.39
7.41
20.66
12.21
7.08
4.08
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) February
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
5.64
4.18 2.19
8.09
10.56
7.50
1.45
1.11
1.26 4.36
2.50
4.00
8.39
17.94
10.54
6.29
4.01
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) March
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
7.58
4.33 2.70
9.41
11.70
9.04
2.15
1.52
1.79 4.05
2.61
4.98 11.06
12.08
6.03
4.92
4.06
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) April
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
6.86
4.50 3.80
8.18
13.07
12.49
3.58
2.17
1.92 3.29
2.40
5.52 11.07
8.51
4.35
4.44
3.84
Wind Speed ( kmh)
1 11 21 31 41 51
151
Joint Frequency Distribution
Stephenville A, NL (1967-2004) May
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
8.27
3.30 2.99
7.95
14.18
10.45
2.57
1.82
1.70 3.73
2.68
6.40 12.93
9.30
3.72
4.53
3.47
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) June
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
11.10
2.57 3.00
6.86
9.52
8.13
2.28
1.44
1.94 4.29
3.03
6.65 16.27
11.96
3.49
4.37
3.10
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) July
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
12.70
1.63 2.57
6.68
8.34
7.03
2.04
1.31
1.98 4.71
3.49
7.90 19.11
12.62
2.99
2.91
2.00
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) August
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
9.88
2.39 3.19
7.21
8.65
6.49
1.33
1.22
1.90 5.36
4.15
7.52 18.15
12.14
3.87
3.89
2.66
Wind Speed ( kmh)
1 11 21 31 41 51
152
Joint Frequency Distribution
Stephenville A, NL (1967-2004) September
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
8.33
3.45 3.80 8.14
9.26
6.42
1.69
1.28
2.38
5.88
3.86
5.63 13.27
12.45
5.93
4.73
3.49
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) October
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
6.25
4.59 3.87
7.82
8.86
7.15
1.82
1.44
2.28 5.44
3.57
4.81
10.24
14.90
7.05
5.62
4.30
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) November
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.58
4.27 3.08
6.60
10.22
8.77
1.92
1.63
2.24 5.05
3.13
3.26
7.40
17.49
9.11
6.78
4.48
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Stephenville A, NL (1967-2004) December
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.42
4.33 3.63
6.57
9.85
9.21
1.80
1.31
1.57 4.40
2.38
2.30
6.96
18.69
11.54
6.59
4.44
Wind Speed ( kmh)
1 11 21 31 41 51
153
Joint Frequency Distribution
Sydney A, NS (1967-2004) January
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.51
5.54 2.37
2.07
1.84
3.12
1.77
2.51
3.09 7.19
7.51
9.90
11.04
19.48
9.45
5.81
4.80
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) February
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.57
9.11
2.86
2.91
2.57
3.50
2.02
2.27
2.71 6.91
7.08 9.07
8.89
17.53
8.84
5.82
5.35
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) March
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.69
11.66
3.82
3.62
3.10
3.55
2.44
2.70
3.60
8.51
8.12
8.56
7.76
12.19
6.52
5.33
5.84
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) April
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.76
12.08
5.85
4.27
3.80
4.86
3.82
3.83
3.85
8.22
7.91
7.53
6.36
9.44
4.92
4.85
5.66
Wind Speed ( kmh)
1 11 21 31 41 51
154
Joint Frequency Distribution
Sydney A, NS (1967-2004) May
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.04
11.91
4.71
4.13
3.63
4.22
3.12
3.39
4.27
10.90
11.12
9.68
6.36
7.11
3.65
3.70
5.06
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) June
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.03
8.86
3.49
2.96
2.49
3.32
2.69
3.27
4.03
11.50
14.14
14.09
8.06
7.75
3.37
2.76
3.19
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) July
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.11
4.86 2.83
2.32
1.69
2.78
2.18
2.51
3.80
13.21
17.26
16.71
9.71
8.26
3.32
2.34
2.11
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) August
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.64
5.45 2.80
2.60
2.07
3.26
2.11
2.24
3.32
10.22
14.43
16.76
11.34
9.53
3.67
2.88
2.68
Wind Speed ( kmh)
1 11 21 31 41 51
155
Joint Frequency Distribution
Sydney A, NS (1967-2004) September
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
4.50
6.99
2.79
2.70
1.95
3.43
2.13
2.33
3.25
9.57 11.24
13.80
10.52
10.75
5.79
4.33
3.93
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) October
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.52
6.90
3.14
2.90
1.75
2.90
2.37
2.67
3.54
8.68 10.25
12.81
10.24
12.09
5.99
5.30
4.96
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) November
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
3.36
6.54
3.16
2.76
2.33
3.14
2.06
2.49
3.49
9.05
8.47
9.37
10.04
14.37
8.08
5.97
5.31
Wind Speed ( kmh)
1 11 21 31 41 51
Joint Frequency Distribution
Sydney A, NS (1967-2004) December
N
S
W E
No observations were missing.Wind flow is FROM the directions shown.Rings drawn at 5% intervals.Calms included at center.
2.46
5.98 2.24
2.27
2.06
3.01
2.45
3.02
3.59 7.32
7.12
8.96
10.69
17.84
9.23
6.16
5.61
Wind Speed ( kmh)
1 11 21 31 41 51