DOCUMENT RESUME

ED 19B 015 SE 034 410

AUTHOR Lucy, Jon: And OthersTITLE The Chesapeake: A Boating Guide to Weather.

Educational Series Number 25.TNSTITUTION Virginia Inst. of Mar in:: Science, Gloucester Point,

Va.SPONS AGENCY National Oceanic and Atmospheric Administration

(DOC), Rockville, Md. National Sea Grant Program.PUB DATE Aug 90GRANT NA79AA-D-00055NOTE 27r.: Contains photographs which may not reproduce

well.AVAILABLE FP OM Sea Grant Communications Office, Virginia Inst. of

Marine Science, Gloucester Point, VA 23062($1.001.

EDRS PRICE MF01/PCO2 Plus Postage.DESrRTPTORS Accident Prevention: *Boat Operators; Climate:

*Meteorology: *Navigation: Safety: *Safety Education:*Weather

TDENTTETTTS *Chesapeake Bay

ABSTRACTThe purpose of this publication is to promote a

better understanding of how basic weather features develop onChesapeake Bav and enable boaters to enjoy the Bay's uniquewaterways. Sections include: (11 Chesapeake Bay climate: (2) generalweather features: f31 seasonal trends: (4) sources of weatherinformation and forecasts: (51 weather service warnings: and (6)weather and boating safety. (Author/C01

***********************************************************************Reproductions supplied by EDRS are the best that can be made

from the original document.***********************************************************************

THE

CHESAPEAKE:a boating guide to

WEATHERU.S. DEPARTMENT OF HEALTH,

EDUCATION& WELFARENATIONAL INSTITUTE OF

EDUCATION

THIS DOCUMENT HAS BEEN REPRO.DUCED EXACTLY AS RECEIVED FROMTHE PERSON OR ORGANIZATION ORIGIN-ATING IT POINTS OF VIEW OR OPINIONSSTATED DO NOT NECESSARILY REPRE-SENT OFFICIAL NATIONAL INSTITUTEOFEDUCATION POSITION OR POLICY

jon lucy, terry ritter, ferry larue

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SEA GRANT PROGRAMVirginia Institute of Marine Science

College of William and MaryGloucester Point, Virginia

2

THE

CHESAPEAKEa boating guide to

WEATHER

by

Jon LucyMarine Recreation Specialist

Sea Grant Marine Advisory ServicesVirginia Institute of Marine Science

And Instructor, School of Marine Science,College of William and Mary

Gloucester Point, Virginia

Terry RitterMeteorologist in Charge

National Weather ServiceNorfolk, Virginia

Jerry LaRueMeteorologist in ChargeNational Weather Service

Washington, D.C.

Educational Series Number 25

First PrintingDecember 1979

Second PrintingAugust 1980

A Cooperative Publication of V IMS Sea Grant Marine Advisory Servicesand NOAA National Weather Service

3

AcknowledgementsFor their review and constructive criticism,

appreciation is expressed to Messrs. HerbertGroper, Chief, Community Preparedness Staff,Thomas Reppert, Meteorologist, Marine WeatherServices Branch and Michael Mogil, EmergencyWarning Meteorologist, Public Services Branch,all of NOAA National Weather Service Head-quarters, Silver Spring, Maryland; also to Dr. RollinAtwood, Marine Weather Instrrctor, U.S. CoastGuard Auxiliary, Flotilla 33, Kilmarnock, Virginiaand Mr. Carl Hobbs, Geological Oceanographer,Vlfv1S. Historical climatological data on Chesa-peake Bay was provided by Mr. Richard DeAngelis,Marine Climatological Services Branch, NationalOceanographic Data Center, NOAA EnvironmentalData Service, Washington, D.C. Thanks go to MissAnnette Stubbs of VIMS Report Center for pre-paring manuscript drafts and to Mrs. Cheryl Teagleof VIMS Sea Grant Advisory Services for com-posing the final text.

This work is a result of research sponsored (inpart) by the Virginia Institute of Marine ScienceInstitutional Sea Grant Program, supported by theOffice of Sea Grant, NOAA, under Grant Number(NA79AA-D-00055). The U.S. Government isauthorized to produce and distribute reprints forgovernmental purposes notwithstanding any copy-right notation that may appear hereon. DESIGN BY DICK COOK

ContentsP AG E

CHESAPEAKE BAY CLIMATE 3

GENERAL WEATHER FEATURES 3

Winds 3

Waves 3

Clouds 5

SEASONAL TRENDS, NOVEMBER THROUGH APRIL.. 5

Fog 6

Cold Air and Water Temperatures 6

Cold Fronts 10

SEASONAL TRENDS, MAY THROUGH JULY 10

Thunderstorms 10

Lightning 12

SEASONAL TRENDS, AUGUST THROUGH OCTOBER 13

Hurricanes 15

Chesapeake Bay Hurricane Holes 15

Waterspouts 17

SOURCES OF WEATHER INFORMATION AND FORECASTS 17

WEATHER SERVICE WARNINGS - WHAT THEY MEAN 20

WEATHER AND BOATING SAFETY 20

---A-MORE-IDEALBOAT ING-area-than -Otiesapeake) Bay would be difficult to find along the Atlantic,

Seaboard With thousands of miles of shelteredshoreline, good water depth and proximity tomajor urban centers, the Bay is a boatman's par,a-disc. However, the Bay's many protected harborsand relatively narrow width (a boatman normallycan keep at least one shore in sight at all times)tend to produce a feeling of false security about

--the-need-to-keep-a-close watch-on- weather- condibons.

The purpose of this publication is to remindboatmen that the-Bay has many different weathermoods, some of which can change quite rapidly.In addition, it should promote a better under-

_ standing of how basic weather features developon the Bay and enable boatmen to enjoy the.,Chesapeake's unique waterways with fewer wea-ther surprises.

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CHESAPEAKE BAY CLIMATE

The climate of the Bay is established by itslocation in mid latitudes on the eastern edge ofthe North American continent. This locationresults in winter climate being regulated by thepolar continental influence, while summer ischaracterized by continental tropical weatherwith infrequent invasions of cooler air. Theclimate is tempered by marine influences whichmost noticeably result in milder winter tem-peratures than those found inland at similarlatitudes.

Fall, winter and spring are characterized byoccasional storm systems producing wind gustsof over 50 knots*, rarely up to 70 knots, aboutonce a year. Such winds usually come fromthe south, northwest or north, but about once inten ?ears strike the area from the east, causingunusually high storm surges.

Summers are characterized by weak low pres-sure systems rarely producing winds as high as 30knots. The Bay also experiences the majority ofits annual average of 30 thunderstorm days duringsummer, and these, of course, may produce thehigher winds noted formerly. Often associatedwith cold fronts, these storms occur most fre-quently from May through August.

Hurricanes are experienced in the Bay aboutonce every ten years, generally coming in the latterhalf of the boating season (August-October).

The Bay's configuration and orientation signifi-cantly affect wind and weather patterns importantto boatmen (Fig. 1). The relatively straight courseof the Bay extends in a north-south direction fornearly 200 miles (332 kilometers). The westernshore of the lower Bay is cut deeply by five tri-butaries varying 2-8 miles (3-13 kilometers) inwidth at their mouths and exhibiting northwestfetches of as much as 20-40 miles (32-64 kilo-meters). On the Bay's eastern shore the numeroustributaries are generally less significant in theirdimensions. The width of the Bay is greatest inVirginia, where the distance between shores rangesapproximately 11-27 miles (18-43 kilometers).The Maryland area of the Bay averages 5-10 miles(8-16 kilometers) in width.

GENERAL WEATHER FEATURES

WINDS

As a very general rule, the prevailing winds overthe Chesapeake tend to follow its north-southorientation. Mid-channel winds can be expected

1 knot = 1 nautical mile pr hour (mph), 1.15 mph or 1.85kilometers per hour.

I

to be southerly during warm months and northerlyduring the cold portion of the year. However, themany smaller bays, inlets, islands and tributaries ofthe Chesapeake interfere with prevailing wind flowpatterns, resulting in local winds which can differdrastically from the general pattern.

Differences in Bay water temperature and airtemperature influence wind direction and speed,particularly as compared to patterns over adjacentland surfaces. During cooler months, the passage oflight, warm prevailing winds over cold water canresult in reduced winds on the Bay as compared towinds inland, unless the warm winds are strong.During warmer months, whenever cold air movesover warm Bay water, winds will be stronger andmuch more gusty over the Bay than over adjacentland surfaces, due to the unstable situation of coldair overlying rising air warmed by the water.

Another characteristic of winds around the Bayis the sea breeze effect. Occurring during warmermonths, sea breeze is caused by differences be-tween air temperatures over the land and water.Basically, air warmed over heat-absorbing landareas is lighter than adjacent air over relativelycooler Bay water. The lighter air rises, causing thecooler air over the Bay to move towards land tofill the void. Sea breeze is noticeable when the twoair masses differ by as little as 5°F (about 3°C) andincreases as differences become greater.

The sea breeze effect is largely responsible forthe strong diurnal variation in wind speeds over theBay during the boating season. When no majorweather disturbances are governing the Bay's windpatterns, winds will tend to be very light at night,increasing in strength during the late morning.Maximum winds occur in mid afternoon whenair mass temperatures over land and water differthe most, with wind speed falling off rapidly atdusk. Such winds are generally stronger nearthe shore, especially where shore elevations arehigher, and at the mouths of rivers. Normalsummer day winds may be nearly calm in theearly morning and increase to approximately 15knots by mid afternoon. As a result of the seabreeze effect, better conditions for high speedboating occur in the morning, while afternoonsgenerally favor sailors.

WAVES

The state of the sea is governed primarily bywind speed and duration, as well as the fetch(distance) over which the wind blows. Windsfrom the north or south have the greatest fetch

3

in the Bay, but northwest winds also have a con-siderable fetch of 20-40 miles (32-64 kilometers)off the mouths of any of the major western shoretributaries. The width of the lower Bay providesconsiderable fetch for strong westerly or easterlywinds associated with major storm systems andcold fronts.

Wind takes time to affect wave height andperiod (time between successive waves). Suddenwind increases or changes in direction may take anhour or more to produce maximum wave heights.Choppy waves are the immediate result of signifi-cant changes in wind speed or direction. A suddensquall does not build huge waves, but rather pro-duces a chaotic sea with steep, short-period waves.However, if the new wind conditions persist longenough, maximum wave heights will be achievedand can cause problems. A rule of thumb for openwaters is, that given sufficient time, wave heightwill increase one additional foot (0.3 meter) foreach seven-knot increase in wind speed.

Water depth and interactions of prevailing wavepatterns with wakes from other craft can affectthe nature of waves. Shallow or shoal water willincrease the steepness of waves, thereby producingdangerous choppy situations which can swamp orcapsize a boat. This must be considered if oneseeks the protection of the lee shore to reduce thefetch of westerly or easterly winds in the Bay.As one moves inside the fish trap (pound netstand) line close to shore, the bottom frequentlyshoals quite rapidly.

Boat wakes can interact with existing waves toproduce a choppy sea, or even unusually highwaves if a wake joins with and enhances an existingwave. Large, swell-like wakes from commercialvessels such as freighters and tankers traversing theBay will also be encountered by recreationalboatmen.

CLOUDS

During much of the year, cloud cover over theBay is essentially the same as that over the adjacentland mass. However, during the spring and sum-mer, when Bay water is cooler than the air over-lying the land, the cooler water inhibits develop-ment of low level cumulus clouds during latemorning and afternoon hours. These clouds maycover most of the sky over land, while the sky overthe Bay will be completely clear (Fig. 2). In fall,the opposite effect results when Bay water iswarmer than the air over land. This situationusually develops with the passage of a cold front

9

00,

Figure 2. Effect of early June water temperatures oncloud cover over the Bay region. Cool air temperature overwater (relative to that over land) inhibits cloud formationover the Bay during late morning and afternoon.

and may result in few if any clouds over the land,while the Bay is nearly cornifletely cloud covered.

SEASONAL TRENDS,NOVEMBER THROUGH APRIL

Much of this period is characterized by roughweather, and it should be treated with caution bythe casual boatman and experienced mariner,alike. However, it is the time of year that manywaterfowl hunters expose themselves to the Bay'selements in rather frail craft, while both ends ofthe period encompass good boating clays. Theperiod is characterized by large weather systemsand storm fronts generally heralded by slowlyincreasing cloud cover and winds. As storm sys-tems move up the Atlantic coast in a northerlyor northeasterly direction, the strongest windsnormally occur ahead of the storm. Over the Bay,in particular its southern half, the leading winds ofsuch storms come out of the northeast quadrantwith speeds of 30-50 knots and higher. Northwest

5

winds, which usually follow these storms, can bequite strong and gusty and may persist for severaldays.

Strong cold fronts also cross the Bay from westto east during November through March, often pro-duced gusty northwest or northerly winds of25-45 knots over open water, while winds a fewmiles inland are considerably lighter. For example,the City of Richmond, Virginia might be ex-periencing northwest winds of about 10 knots,while along the shore at the Bay mouth windvelocities are at least 50 percent higher. The un-stable condition of cold air moving over therelatively warm water, as well as reduced frictionsurface presented by the water, are responsiblefor the gustier winds over water. Regarding thisphenomenon, remember that a doubling of windvelocity results in a four-fold increase in windforce, a tripling in velocity a nine-fold increase,etc. (Force = Mass x Velocity2).

Naturally, wave conditions associated with theblustery winds of the period can become quitesevere and prove hazardous to small and mediumsize boats. Problems with bad chop resulting fromwinds opposing strong tidal currents are also morepronounced during this time and have to beconsidered. Northerly winds of 25 knots or higherhave a long fetch down the Bay and can easilybuild wave heights to 5-7 feet (1.5-2 meters) in itssouthern extremities. Westerly winds producetheir highest waves in the widest section of theBay, particularly east of the Potomac and Rappa-hannock Rivers. At the mouths of these and otherlarge rivers, tide and wind also can interact tofurther aggravate wave conditions. Easterlywinds will produce their highest waves along theseaside beaches and at the Bay mouth wherenortheasters can result in wave heights of 10 feet(3 meters) or more.

FOG

Fog can become a serious problem, especiallyfrom January through April. Most of the Bay's30-40 dense fog days per year occur during thispeiiod. Fog on the Bay most often forms whenwarm moist air with a dew point higher than theBay's water temperature moves over the area fromthe south to southeast. (Dew point is that tem-perature at which the air's moisture contentreaches saturation point or 100 percent relativehumidity). As the warm moist air passes over thecooler water, the air can drop in temperature toits dew point and its water vapor can condense into

6

minute water droplets (fog). Formation of densefog is more common as one moves offshore, andshould be anticipated on unusually warm, humiddays during winter or spring. Visibility during coldseason fogs will often be near zero if winds are lessthan 10 knots. Higher winds will produce slightlybetter visibility, but still much less than one mile.

Although it happens frequently, fog shouldnever catch the observant boatman totally by sur-prise. There are several good clues indicating thatfog formation is imminent. According to DonaldWhelp ley in Weather, Water and Boating (CornellMaritime Press, Inc., Cambridge, MD, 1961) andWilliam Kotsch in Weather for the Mariner (2ndEdition, Naval Institute Press, Annapolis, MD,1977) fog formation is likely if:

* Fog formed in the same area the previousnight and weather conditions are still re-latively unchanged

* There are sustained, warm, moist winds outof the south blowing over colder land orwater surfaces

* The daytime sky appears hazy and not veryblue, while the horizon is ill-defined; atnight, light beams appear misty

* The sky is clear at sunset, the wind light andthe air humid

* The difference between air temperature andthe dew point (determined with a slingpsychrometer) is 10°F (5-6°C) or less and theexpected minimum temperature will be closeto the present dew point

Once fog has set in, Whelpley states there arecertain things to look for that signal it will breakup:

* If fog was in the area the previous day andlifted, it will likely lift about the same timeagain

* If the air temperature is rising, the fog will"burn off" as the air temperature rises abovethe dew point; however, if moderate windsare blowing, the warming trend will be slow,and if rain is falling through the fog, therewill be no heating by the sun, furtherslowing the warming process

* Changes in wind direction or increases inwind velocity can move the fog out of thearea or lift it off the water surface, im-proving visibility

COLD AIR ANDWATER TEMPERATURES

Fall, winter and early spring bring with them

TABLE 1. AVERAGE SURFACE WATER TEMPERATURES ( °F)' IN CHESAPEAKE BAY

LocationYears of

Observations Jan Feb Mar Apr May JunMonthJul Aug Sep Oct Nov Dec

Little Creek, VA(Norfolk)36 55'N 76 11'W

6 40 41 47 55 66 74 79 80 75 1 66 55 45

Solomons, MD(Patuxent River)38 19'N 76 27W

32 38 38 43 53 65 74 80 80 76 165 54 43

Baltimore, MD 56 37 37 43 53 64(Patapsco River)

39 16'N 76 35W

PotentialHypothermiaPeriod

74 80 80 75 1 65 54 43

PotentialHypothermia

Period

* °C = 9.556 (°F-32)

Source; United States Coast Pilot 3, Atlantic Coast, Sandy Hook to Cape Henry, 15th Ed., National Ocean Survey, NOAA,Washington, D.C., July 1977.

low air and water temperatures that can be silentkillers. Falling overboard or capsizing during thecooler months of the year can prove fatal, althoughnot directly from drowning. Emersion in coldwater (water cooler than 70°F or 21°C) quicklylowers the body's core temperature and can be aproblem in the Bay from October through May(Table 1). Called hypothermia, the lowering ofbody core temperature first results in shivering,then los', of manual dexterity and finally musclerigidity. Continued cooling brings on mentalconfusion, which renders a person powerless tohelp himself. Unconsciousness soon follows,and if drowning has not occurred before coretemperature reaches 85°F (29.5°C), heart failurecompletes the scenario.

Wearing a close fitting, garment type foamflotation jacket can dramatically increase survivaltime over 300 percent in cold water. The nextbest precaution is wearing a more standard typepersonal flotation device so that you do not haveto tread water or swim to stay afloat. Heat lossoccurs primarily from the head, chest and groinareas of the body and movement causes a greater

rate of loss. If in cold water with no flotationdevice, never use the drownproofing method ofperiodically >ubmerging the head, since this is oneof the quickest ways to lose body heat (Table 2).

A flotation device allows one to assume theHeat Escape Lessening Position (H.E.L.P.), ifalone in the water, or the HUDDLE position(Fig. 3). In 50°F (10°C) water, survival time usingH.E.L.P." or the HUDDLE position is approxi-mately four hours, as compared to only two hourswhen having to swim or tread water. At mid-winter Bay water temperatures (approximately35°F or 1.7°C), the H.E.L.P. and HUDDLE posi-tions provide about 2.7 hours survival time ascompared to 1.2-1.4 hours for swimming or tread-ing water without a flotation device (Fig. 4). Re-member that all survival times indicated herein arefor the "average" person. Small people cool fasterthan large people, children faster than adults andthin people faster than fat people.

Cold air temperatures can also cause hypo-thermia in boatmen inadequately dressed or whoseclothes got wet from spray. Multiple layers of lightclothing provide better protection than one heavy

7

TABLE 2. PREDICTED SURVIVAL TIMES FOR AN AVERAGE PERSONIN 50°F (10°C) WATER*

SITUATION SURVIVAL TIME (HOURSI

NO FLOTATION

Drownprooi ing 1.5

Treading Water 2.0

WITH FLOTATION

Swimming 2.0

Holding still 2.7

H.E.L.P. or HUDDLE 4.0

UVic Thermofloat Jacket 9.5

* Clothing worn was cotton shirt, pants, socks plus running shoes.

Source: University of Victoria research results presented at the "Cold Water Survival and Rescue Symposium" sponsoredby the U.S. Coast Guard and American National Red Cross, Santa Rosa Junior College, Santa Rosa, CA, Feb., 1979.

garment. If spray is anticipated, a water repellentor waterproof outer garment should be worn. Ifboating in cold weather, watch fellow crew mem-bers for signs of sluggishness, slurred speech ormental confusion, all signs of creeping hypo-thermia. Using proper methods for re-warming

hypothermia victims is essential, and such methodsare described in appropriate pamphlets availablefrom the U.S. Coast Guard.

Also remember that when you add wind ex-posure to existing low temperature conditions,the actual chilling effect on exposed flesh is much

Treading water Drownproofing No H.E.L.P. H.E.L.P. Huddle

Figure 3. Possible in-the-water survival positions; the H.E. L.P. and HUDDLE positions provide the greatestsurvival times (adapted from "Cold Water Survival and You." Chesapeake Bay Magazine 8 (7), 1978.J. Groene).

812

Comparative Cold Water Survival Times20

18

16

14

12

10

8

6

4

2

HELP POSITION I: IHUDDLE POSITION /I iNORMAL FLOATING W/PFD

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25 35 45 50

TEMPERATURE ( Degrees F.)

Figure 4. Effect of in-the-water survival positions on survival time(Source: U.S. Coast Guard).

greater than under still conditions. Brisk windconditions in combination with temperaturesslightly below freezing can produce the samechilling effect as temperatures 30-40°F (17-22°C)

55 65 70

lower in still conditions. The following windchill table (Table 3) should be used to bettergauge how much cold weather protection isneeded.

TABLE 3. WIND CHILL

Equivalent Temperatures CFI

CALM 35 30 25 20 15 10 5 0 -5 -10

10 II 22 16 10 3 -3 -9 -15 -22 -27 -34

20Ia 12 4 -3 -10 -17 -24 -31 -39 -46 -53

1

30 i 6 .2 -10 -16 -25 -33 -41 -49 -56 -64

ao 3 -5 -13 -21 -29 -37 -45 -53 -so -69

°C = 9,556 (°F-32)

Source: "Riding Out Winter Storms," National Weather Service. NOAA, PA 79015.

9

13

COLD FRONTS

Thunderstorms are not normally experiencedduring the cold months. March and April, how-ever, bring an increase in such activity. Duringthese months thunderstorms almost always precedecold fronts, but will often decrease in intensityafter moving over colder waters. Such frontsgenerally move out of the western quadrantstowards the east at speeds between 10-30 knotswith advancement generally faster in winterthan in summer. Because cold fronts normallyhave a sharply sloping leading edge, they upliftwarmer air ahead of themselves rather abruptly,with the result that such frontal storms are usuallyviolent. The only saving grace is that the steeplysloping frontal edge also means that frontal wea-ther is generally limited to a very narrow band orzone. Therefore, the violent frontal storm isusually brief in duration.

Major squall lines frequently precede coldfronts as much as 100-150 miles (161 -241 :Ho-meters). Because squall lines frequently pack sud-den, strong winds of 34 knots or more, the Na-tional Weather Service may issue a Severe Thunder-storm or Tornado Watch as well as a SpecialMarine Warning. A "watch" usually precedesstorm arrival by an hour or more. Special Marine

Warnings are issued for winds of 34 knots orhigher and waterspout sightings, Severe Thunder-storm Warnings for winds of 50 knots or higherand Tornado Warnings for tornadic winds whenthere is good evidence that any of these condi-tions will occur within one hour.

SEASONAL TRENDS,MAY THROUGH JULY

Typically, weather in this period is fair, withoccasional storms. The land and water warmrapidly in May, reaching peak temperatures inJuly and August. Most of the time the weatheris characterized by clear skies and light to mode-rate winds. However, the most active thunder-storms of the year also occur during this period,producing local squalls with winds up to 50 knotsor higher.

THUNDERSTORMS

Thunderstorms pose considerable danger toboats because of their strong, gusty winds andlightning. They are formed by rising air currentsand normally occur during maximum heating ofthe Earth's surface, or from mid afternoon through

Figure 5. Rapidly approaching clouds at the leading edge of a thunderstorm indicate trouble for smallboats. An alert skip-ler will head for a protected anchorage well ahead of such storms.

10

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Figure 6. With a thunderstorm bearing down from astern, these boatmen are a bit tardyin seeking the protection of shore.

early evening. However, cold fronts also causewarm surface air to rise up over their leading edgeand likewise can produce thunderstorms anytimeday or night. Whenever the passage of such a frontcoincides with the time of maximum daily heatingof the Earth's surface, the most violent thunder-storms usually result. Visible indications thatunusually strong winds are accompanying anapproaching thunderstorm may be the follow-ing:

* A rapidly approaching thunderstorm withwhat appears to be a heavy fog bank under it

* Unusually frequert lightning and thunderin an approaching storm

* A rapidly approaching low cloud or line oflow clouds, with or without a thunder-storm (Fig. 5)

During spring and early summer about six daysof each month include thmderstorms. Thesestorms develop to the \\ est over land and mostoften move out of the southwest at speeds aver-aging 25-35 knots. A particularly careful watchshould be kept on the occasional storm approach-ing out of the northwest. Such thunderstormshave proven to be especially severe, tending to

aft. --aairra....11M.,_11

move more rapidly than normal and sometimespacking peak winds of 70-90 knots. This typestorm struck Norfolk, Virginia, in June 1977capsizing a head boat and tearing away the end ofa fishing pier.

As summer progresses, weather fronts becomeweaker, and most of the thunderstorms resultfrom the sun heating the earth's surface. Thesestorms develop over the land mass to the westbut move more slowly than the storms of springand early summer. Their normal rate of approachis about 10-20 knots or less. During July the Baymay experience 8-9 days of thunderstorms, withAugust averaging 6-7 days.

Boats should head toward safe anchorage when-ever a thunderstorm is considered to be approach-ing (Fig. 6). Storms will generally move in fromthe southwest, west or northwest, but they mayalso come out of either the south or north. Us-ually, thunderstorm activity observed in any ofthe eastern quadrants is not of concern, since sucha storm is already past your location. Alwayshead for shelter sufficiently in advance of anapproaching thunderstorm, since it frequentlyadvances at speeds greater than the normal cruisingspeed of most boats.

11

4

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LIGHTNING

The winds accompanying thunderstorms are notthe only problem such weather systems pose forboats on the Bay. Lightning from these stormsoccasionally strikes boats and is capable of doingconsiderable damage to property and people(Fig, 7). More than 100 persons are killed annuallyby lightning strikes in the United States.

Radio antennas and sailboat masts are the itemson boats most frequently hit by lightning. Theyshould be properly grounded according to methodsdescribed in the National Fire Protection As-sociation's Lightning Protect ion Code of 1977.All large metal objects aboard a boat should beconnected to a ground system consisting of at leastNo. 8 copper wire (approximately 1/8 inch or 3millimeters diameter). The ground connection;nay consist of any metal surface normally sub-merged which has an area of at least one squarefoot (929 square centimeters). Propene' s1 metalrudder, centerboard or keel can be used fur theground connection as well as copper plate of f ixedto the hull.

Remember: The 60° arc cone of protection(Fig. 8) established over a boat by proper ground-ing procedures does not provide absolute safetyf rom lightning. A direct strike can occasionally

PROTECTED ZONESTAYS GROUNDED

PROTECTED ZONE -

PROTECTED ZONE........i.L,TAN TENN4

ANTENNA WITHOUT LTL,-TTN/N6ARRE7TER OR GAP .('' N COIL

.,/' ck' ,"-- 17......,....

Pr;CTE prep ZONE

./'. .../' \.....,.../ ,..

Figure 8. The best lightning protection for small boatsis provided by a proper ground system. For best results,ground the highest structure on your vessel.

1(

enter the area of protection, or a person aboard a"protected" boat can be struck by a side flash oflightning capable of jumping 5-6 feet (1.5-1.8meters) to a ground of less resistance.

A thunderstorm's electrical activity can be usedto tell something about the storm's distance andintensity. Because light travels about a milliontimes faster than sound, the distance in miles toa thunderstorm can be estimated by counting thenumber of seconds between lightning and thunder,and dividing by five (sound travels about 1/5 mileor 0.3 kilometer per second).

A simple AM radio can also warn of impendingthunderstorms and lightning problems. In additionto producing static in harmony with lightningdischarges from an approaching storm, the radiocan tell a boatman when the charged water areaassociated with a thunderstorm surrounds his boat.According to Thorn Bacon in Weather for Sports-men (The Hearst Corporation, N.Y., N.Y., 1974)an AM radio will produce loud hissing or sizzlingnoises (a bacon frying sound) when a storm's"electrical shadow" overtakes a boat.

Warnings of an approaching storm should beheeded and precautions taken long before rainoccurs. In the Florida Sea Grant PublicationBoating Safety - Thunderstorms (Marine AdvisoryProgram, University of Florida, Gainesville, FL32611, 1978), Walter Sitarz, Miami's Port Me-teorological Officer for the National Weather Ser-vice, emphasizes that in many instances of light-ning casualties, no rain was falling at the time ofthe lightning strike. Frequently, strikes occurredjust prior to the onset of a thunderstorm.

Sitarz recommends taking the following light-ning precautions aboard a boat caught in a thun-derstorm, even if the boat is properly grounded:

* Remain in the center of the cabin of aclosed boat when possible.

* Don't go in the water or swim until thestorm passes.

* Keep away from any metal fittings aboardthe boat, particularly those which areconnected to the lightning conductive(ground) system.

* Disconnect the major electronic equipmentnot being used.

* Don't touch the radio equipment or wiring.* On small power boats, lower the radio

antenna and keep a low profile below thefreeboard.

* Ground small sailboats without sophisticatedelectronic systems by using a length ofbattery cable which is clamped to the wire

stays of the mast and allowed to hung overthe side into the water.

* If the boat is near shore, seek refuge under abridge.

* After any lightning storm passes, check theelectrical system and compass. Lightningstrikes have been known to alter the mag-netic characteristics of a boat.

Several additional precautions are recommend-ed by Terry Ritter, Meteorologist in Charge,National Weather Service, Norfolk, Virginia:

* If you must ride out a thunderstorm in aboat, try to avoid shallow water; it does notinsulate a boat from the earth as well asdeep water.

* If you feel your body hair stand on end oryour ;kin tingle, lightning may be about tostrike you. Drop to your knees and bendforward, placing your hands on your knees.Do not lie flat.

A person struck by lightning receives a severeshock and may be burned externally as well asinternally. However, the body retains no electricalcharge and may be handled safely. A personapparently "killed" by lightning can often berevived by prompt, prolonged mouth-to-mouthresuscitation and cardiac massage.

SEASONAL TRENDS,AUGUST THROUGH OCTOBER

This is a fair weather period, although markedby several unusual weather phenomena. Airtemperatures begin a slow decline during latesummer, the decline becoming more rapid in lateSeptember and October. The increasingly coolertemperatures bring a rather abrupt end to thefrequent thunderstorms of July and August. Upto 6-9 thunderstorm days per month are typicalfor portions of the Bay during July and August,while September and October produce only 1-3such days. Thunderstorms during these lattertwo months, while rare, are almost always asso-dated with told fronts that now begin to becomemore vigorous.

The increasing frequency of cold fronts alsomarks a slight overall increase in the percentageof days the Bay experiences dense morning fog.Boatmen need to become fog-wary once again,especially from Annapolis north. The upperreaches of the northern Bay appear to experience

1713

more fog (1-4 days per month) than other areas.During September and October. the Marylandportion of the Bay generally experiences morefoggy days than Virginia waters. Morning fogis the rule, with dense afternoon fog generallyexperienced less than one day per month on theaverage throughout the boating season.

In spite of an increasing number of cold fronts,the overall weather pattern for the period is

Figure 9. Here are some ofthe many Chesapeake Bayhurricane holes providing

good vessel anchoragesduring periods of

high winds.

14

dominated by high pressure systems. Particularlyduring September and October, long spells offair, pleasant weather prevail. It is important tokeep in mind, however, that water temperaturesbegin to dip below 70°F (21°C) again in October,making hypothermia a danger once more foranyone finding himself unexpectedly in the waterfor an extended period of time.

53)

HURRICANES

The fair weather of August through Octoberunfortunately brings with it one "demon" that Bayboatmen must expect to encounter on the averageof once every ten years--the hurricane. Virginia'shurricane season extends from June 1 throughNovember 30, with a peak between mid Augustand the first week of October. The activity peakreflects an increase in the number of hurricanesspawned in the southern North Atlantic that tendto track parallel to the East Coast.

Although hurricanes are rare in ChesapeakeBay, near-hurricane force winds (greater than 64knots) are not uncommon because of severethunderstorm activity and summertime squalls.This makes it important for boatmen to know thelocation of well-protected harbors that providegood landlocked water with adequate depth fordeep draft vessels. So-called ''hurricane holes"are present in most Bay tributaries, according toJulius Wilensky in "83 Hurricanes Ho /es of theEast Coast" (Sea Magazine, August 1978, CPSPublications, Inc., N.Y., N.Y., Copyright 1978).Locations of hurricane holes follow (Fig. 9),as recommended by Wilensky and Jon Lucy(indicated by an asterisk).

Chesapeake Bay Hurricane Ho /es

LOWER BAY (south to north)

Western Shore

1) Linkhorn Bay, off Lynnhaven Bay aboveCape Henry* -- Enter Lynnhaven Inletcautiously because of a shifting bar, butanticipate a well-marked entrance channelwith water depths of 6-10 feet (1.8-3meters); the Inlet and the east channeltowards Linkhorn Bay are crossed byfixed bridges with 35 foot (10.7 meter)clearances; after entering the Inlet, swingwide to the left towards the Great NeckRoad Bridge and proceed into Broad Bay,then through the 6 foot (1.8 meter) deepNarrows into Linkhorn Bay; protectedanchorages can be found in both the southand east branches of the Bay to either sideof Bird Neck Point, with shoreside facilitiesat the ends of each branch.

2) Hampton River, north shore inside Hamp-

ton Roads* -- Cross Hampton Roads BridgeTunnel and enter the channel to the rightbehind the Tunnel island; as you enter thdmouth of Hampton River, be on the look-out for commercial tug and barge traffic;proceed up Sunset Creek on the left wheretwo marinas handle limited numbers oftransient boats; do not anchor in theHampton River channel because of bargetraffic and the River's northeast orien-tation.

3) Lower York River, north shore* - -. Afterpassing Sandy Point, look for day markersindicating the winding channel into thePerrin River where dockage can be foundat the large marina. Drafts of seven feet(2.1 meters) can be accommodated. Evenbetter protection is offered further up theriver in Sarah Creek where good anchorageswith water depths of 7-8 feet (2.1-2.4meters) are available in the northwestbranch up to the repair yard and marina,and in the northeast branch as far as theoyster packing house on the north shore.

4) East River, off Mobjack Bay -- Anchoreither in Putam Creek or in East Riveritself, south of Woodas Point.

5) Corrotoman River, lower RappahannockRiver, north shore After clearing theGrey's Point bridge, (vertical clearanceof 110 feet or 33.5 meters), anchor ineither of the Corrotoman's branches;7 foot (2.1 meter) drafts can be car-ried 2%2 miles (4 kilometers) up theeast branch, while the west branch canhandle 8 foot (2.4 meter) drafts forthe same distance.

6) Dividing Creek, north of Fleets Bay, aboutmidway between Rappahannock and Poto-mac Rivers Anchor up the creek justabove Lawrence Cove.

7) Horn Harbor, about 5 miles (8 kilometers)up Great Wicomico River, north shoreThis is the best of several well protectedcreeks going upriver.

Eastern Shore

8) Cape Charles Harbor* -- This harbor ofrefuge located nine miles (14.5 kilometers)

1915

north of the Cape itself can provide pro-tection with transient docks located in thenortheast corner behind the Coast GuardStation; for boats drawing less than fivefeet (1.5 meters), Kings Creek just northof the harbor also offers protection as wellas marina services, but the channel markersmust be followed carefully.

9-10) Occohannock and Nandua Creeks* --

Some protection can be found in Occo-hannock Creek up to the area of DavisWharf, beyond which water depths dropbelow 7-8 feet (2.1-2.4 meters). NanduaCreek to the north has a somewhat tricky,winding channel bordered by shoals, butwith care, protection can be found byrunning up to Nandua.

11-12) Pungoteague and Onancock Creeks* --Good protection is found up PungoteagueCreek in the area of Harborton; furthernorth Onancock Creek provides good stormanchcrage in the area of the Onancocktown dock.

13) Saxis, upper Pocomoke Sound* -- Pro-tection is available in the commercialfishing harbor for boats requiring depths of6 feet (1.8 meters) or less.

MIDDLE BAY (south to north)

Western Shore

14) St. Mary's River, lower Potomac, northshore The new harbor of refuge dredgedto 8 feet (2.4 meters) 1 1/2 miles (2.4 kilo-meters) up the Potomac from Point Look-out may prove satisfactory unless highwater forces waves over the breakwater;best to continue up to St. Mary's Riverwhere good anchorages exist oppositePagan Point or above Horseshoe Point;Carthegena and St. Inigoes Creeks alsooffer good protected anchorages.

15) Mill Creek, Patuxent River, north shoreat Solomons -- Go up to where the creekwidens just east of Old House Cove.

16) Mill Creek, Patuxent River above bridge,western shore -- Another Mill Creek about4 V miles (7.2 kilometers) above river

16

mouth offering good protection; fixedbridge under construction will have 140foot (42.7 meters) vertical clearance.

17) Patuxent River, above the Potomac River --Anchor behind one of many bends afterthe river narrows somewhat, or go up oneof the creeks suiting your draft; theentire river is well shown on NOS ChartNO. 12264.

Eastern Shore

18) Crisfield, off Tangier Sound* -- Anothercommercial harbor where water depths ofat least 7 feet (2.1 meters) are availableand service facilities are good.

19) Nanticoke River, Tangier Sound, behindBloodsworth Island -- Anchor up in theriver off the channel or in any of the manycreeks up the length of the river.

UPPER BAY (south to north)

Western Shore

20) Rhode River, south of Annapolis betweenWest and South Rivers -- Go up past theflashing green light and anchor betweenHigh Island and steep south shore or go upSillman Creek (7-8 foot or 2.1-2.4 meterdepths).

21) Little Round Bay, up Severn River, offRound Bay -- Above Annapolis one mustopen a bascule highway bridge and aswinging railroad bridge, then clear a fixedhighway bridge (80 foot or 24.4 metervertical clearance); anchor in Little RoundBay west of Round Bay, staying eithernorth or west of St. Helena Island; creeksabove and below Round Bay are also goodanchorages.

22) Stony Creek, off Patapsco River, southshore Excellent protection is found inupper reaches, e.g. between Sloop Coveand Long Cove or in Nabbs Creek, as wellas in other coves and creeks.

23) Frog Mortar Creek off Middle River, northshore -- One of several good creeks offMiddle River; go to upper reaches of riverpast the marinas; the best room and pro-

tection is found in the west fork east ofMartin Marietta Airport (5-7 foot or 1.5-2.1 meter depths).

Eastern Shore

24) Dun Cove, off Harris Creek, behind Tilgh-man Island -- Anchor in either of thetributaries extending north and northeastfrom the cove; Harris Creek offers goodprotection where it narrows before dividinginto two branches; the Choptank Riverimmediately to the south of Harris Creekalso offers good protection in its tributariesand the bends of the river above Cam-bridge.

25) Tred Avon River, north of entrance toChoptank River -- Good anchorages can befound above Oxford in Plaindealing Creekand Trippe Creek, as well as other creeksfarther up the river.

26) Miles River, behind Tilghman Point -- Bestprotection is found in Leeds or HuntingCreeks on the north shore, or above thebascule bridge in the river itself; Glebe andGoldsborough Creeks are also safe anchor-ages.

27) Wye River, north of Miles River -- Get be-hind one of the river's many bends, inone of the creeks to the east or anywherearound Wye Island.

28) Chester River, north of Kent Island --About 11 miles (17.7 kilometers) upriveron the west bank, Reed Creek provides agood anchorage; the river on up to Chester-town offers good protection in severaltributaries or in the river itself behind oneof the many bends.

29) Sassafras River, head of the Bay TurnerCreek, 4 1/2 miles (7.2 kilometers) abovethe mouth on the south shore, offers thebest protection, although the entranceis narrow; good protection can also begained by anchoring off the channel atbends in the river up to Georgetown.

Remember, the anchorages mentioned here maybe crowded because of their popularity. If youmust look elsewhere for good protection, look forbodies of water in which an extra high tide up to

2.1

12 feet (3.7 meters) above mean high water can behandled. Also remember that if you are actuallyexpecting the eye of a hurricane to come ashore inyour area, the best protection in the NorthernHemisphere is in the left rear quadrant with 'respectto where the storm's eye is expected to intersectthe coast (determine the left rear quadrant whilefacing away from the approaching storm along itsprojected track).

In seeking protected anchorages, also rememberthat a hurricane usually will produce cast or north-east wind speeds of 70-100 knots, followed bylesser winds from the west or northwest. A hurri-cane's high winds and tides also require that anchorline scope be increased from the usual 7:1 ratio toa 10:1 ratio. If a protected harbor has limitedswing room for anchored craft, two anchors shouldbe used 180 opposed to each other. Reduce thelikelihood of dragging by anchoring in sand or hardmud rather than grassy bottom or soft mud.

Waterspouts

Waterspouts are occasionally sighted in the Bayand should be avoided because of their potentiallydestructive nature. Strangely enough, the pheno-menon occurs most often during fair weather inlate summer and early fall. Fair-weather water-spouts are caused by cooler air overriding a bodyof warm moist air and are usually associated withcloud build-up over the Bay. At the cool/warm airinterface, conflicting wind patterns often describecircular patterns, producing a usually short-livedcolumn of wind and water with wind speeds of 50knots or less. However, a boat struck by such awaterspout can sustain considerable damage.

Another type of more dangerous waterspoutmay form in association with the leading edge of acold front or the squall line associated with afront. Such waterspouts are truly tornados overthe water, and winds may exceed 200 knots. Theyshould be avoided at all cost because of theirdestructive winds and low pressure interior. If awaterspout appears to be approaching your boat,steer a course 90° perpendicular to the spout'spath. A moored boat in the path of a tornadicspout should have its hatches and ports open tohelp equalize the pressure within the boat as thespout passes.

SOURCES OF WEATHERINFORMATION AND FORECASTS

Chesapeake Bay normally is divided into twoforecast areas, with Windmill Point at the mouth

17

of the Rappahannock River being the dividingpoint. While this breakoff point is partly a matterof convenience, it is significant in that the portionof the Bay to the north generally experiencesfronts 6-12 hours ahead of the southern Bay area.Slow moving systems also may linger 6-12 hourslonger in, or even stall over, the lower Bay.

Under unusually extreme weather conditions,the Bay may be divided into four separate fore-cast areas to allow more detailed forecasting. Anyappropriate combination of the areas may also beutilized for making forecasts. The forecast zonesare: (1) north of Baltimore Harbor, (2) BaltimoreHarbor to the Patuxent River, (3) Patuxent Riverto Windmill Point and (4) south of WindmillPoint. The tidal portion of the Potomac River (5)may be singled out as a fifth forecdst area (Fig.10).

Figure 10. National WeatherService (NWS) forecast areas for

Chesapeake Bay and adjacentoffshore waters; locations

of NWS VHF-FM transmitters areindicated by ( ).

18

Forecasts for the ocean side of the easternshores of Maryland and Virginia are called coastalforecasts and cover an area from Cape Henlopen,Delaware to the Virginia/North Carolina line and20 miles out to sea. The coastal forecast normallycovers this entire area at one time, but it may bebroken into a northern and southern componentwith Chincoteague, Virginia as the breakoff point(Fig. 10).

Prudent boatmen planning an outing on theBay should begin monitoring marine weatherforecasts 12 to 24 hours in advance of their de-parture time. Weather-wise mariners will alsostart taking mental or even written notes on basicweather conditions in this same time frame. Thishelps one to achieve a sense of the developingweather patterns that are likely to be experiencedwhile on the Bay.

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od

The most complete and current weather fore-casts and warnings for the Chesapeake Bay andcoastal areas are taped and broadcast over VHF-FM radio channels by National Weather Serviceoffices every 4-6 minutes, around the clock. Theyinclude the latest marine forecasts, special weatherstatements, warnings and observations for bothland and marine areas. Observations are updatedevery three hours by Weather Service personnel.Forecasts are updated every six hours, at approxi-mately 5:00 a.m., 11:00 a.m., 5:00 p.m. and11:00 p.m. Amended forecasts arc issued when-ever observed conditions differ significantly fromthe taped forecasts.

National Weather Service VHF-FM transmittershave an approximate line of sight range of 30-70miles (48-113 kilometers), depending upon thesensitivity of individual receivers. The broadcastsfrom these stations can be picked up on permanentVHF radios carried in many boats, or on inexpen-sive portable VHF radios. More expensive portableunits contain an alarm tone that is automaticallysounded when weather warning broadcasts aremade. Appropriate transmitter locations areindicated in Table 4 and Figure 10.

TABLE 4.TRANSMITTER LOCATIONS AND FREQUENCIES

Norfolk, VA 162.55 MHz (Weather 1)

Richmond, VA 162.475 MHz (Weather 3)

Manassas, VA 162.55 MHz (Weather 1)

Heathsville, VA 162.40 MHz (Weather 2)

Salisbury, MD 162.75 MHz (Weather 3)

Baltimore, MD 162.40 MHz (Weather 2)

The U.S. Coast Guard also transmits weatherinformation in combination with "Notice toMariners" reports on a Single Side Band frequencyof 2671.4 KHz. These broadcasts are made atscheduled times only, but have a range of 200-300miles (322-483 kilometers). Bay forecasts aremade at 9:33 a.m. and 10:30 p.m. EST fromGroup Hampton Roads and Group Eastern Shore.Weather warnings are broadcast upon receipt onthe same frequency as well as on VHF-FM fre-quency 157.1 MHz (Channel 22) from HamptonRoads and Baltimore. All Coast Guard stations

TABLE 5. MARINE FORECASTSFROM TELEPHONE RECORDINGS

FORECASTAREA

Hampton Roadsand Vicinity

TELEPHONENUMBER

(804) 853-3013(Norfolk)

Lower Chesapeake (804) 222-7411Bay (Richmond)

Baltimore toPatuxent andTidal Potomac

(202) 899-3210(Wash., D.C.)(301) 761-5380(Baltimore)

COMMENTS

Can hold line forforecaster between6:00 a.m. and 6:00p.m.

Can hold line forforecaster between9:00 a.m. and 5:30P.m.

Forecaster availablebetween 9:00 a.m.12:00 p.m. and 1:00p.m. - 4:00 p.m.

broadcast severe emergency weather warnings(Special Marine Warning Bulletins) on VHF-FMfrequency 156.8 MN, (Channel 16).

Coast Guard weather forecast information,derived from the National Weather Service, is alsobroadcast at prescribed times by the NorrolkMarine Operator. Broadcasts are made at 6:00a.m., 12:00 p.m., 6:00 p.m. and 12:00 a.m. ESTon Single Side Band frequency 2538 K1-1/ andapproximately 10 minutes later on 2450 K1-1/.Weather warnings are broadcast when received,with repeat broadcasts customarily IS minuteslater, and then at 1-2 hour intervals.

National Weather Service offices throughoutthe Bay area also provide a telephone marineweather information service for the onshoremariner (Table 5). Because of the large demandfor this japed message service, the lines are fre-quently busy.

Another source of marine weather forecastinformation is commercial AM and FM radiostations and television stations. Numerous stationsaround the Bay include marine information intheir regular weather forecasts. A few stations atthe mouth of the Bay and in the Baltimore areahave their own boats on the water during the boat-ing season's weekend and holidays. These boatsreport current marine weather conditions andforecasts over the air. However, care should beexercised in using only commercial radio andtelevision stations for weather information, sincetheir forecasts and weather warnings arc notalways up-to-the-minute because of communi-cation delays.

2319

A final source of weather information, grad-ually being phased out, is the warning displaysignal. Signals are posted at many marinas, CoastGuard stations and other prominent boatingcenters, primarily during daylight hours only.The signals consist of a single red pennant for asmall craft advisory, two red pennants for a galewarning, a single square flag with a Hack centerfor a storm warning, and two such square flags fora hurricane warning.

WEATHER SERVICE WARNINGSWHAT THEY MEAN

SMALL CRAFT ADVISORY -- Such advisoriesare issued when wind and sea conditions are ex-pected to cause problems for small craft. Althoughthe term "small craft" has never been defined, itis considered to pertain to boats up to approxi-mately 24 feet (7.3 meters) in length. During thewarmer season (April-November), advisories areissued when winds of at least 20 knots are ex-pected, since such winds can produce three foot(0.9 meter) waves. During the colder months(December-March), minimum conditions forissuing advisories are winds of 25 knots, which cangenerate up to four foot (1.2 meter) waves. SmallCraft Advisories are just what they say - advice.In giving this "advice" the National Weather Ser-vice must assume that boatmen know the capa-bilities of their individual craft and can judgewhether it is safe to venture out in their particulararea.

SPECIAL MARINE WARNING -- Such warn-ings are issued when sudden strong winds of atleast 34 knots are expected. The most frequentuse of Special Marine Warnings is for approachingsevere thunderstorms, but a waterspout sightingreport or a strong cold front packing brief butsufficient winds might require a warning. Fore-casters generally have rather limited informationconcerning the actual strength of winds in severethunderstorms or the area of the Bay such stormsmight actually strike. Therefore, when a warningis issued fo1 these severe storms, boatmen shouldimmediately seek protected waters. In seeking alee shore, remember that the strong, gusty windsassociated with thunderstorms will come from thesouthwest to-northwest direction in nearly everyinstance on the Bay.

20

GALE WARNINGS - - Such warnings are madeWhen prolonged winds of 34-47 knots are expect-ed. In unprotected waters, 35 knot winds can buildup five foot (1.5 meter) waves. Only the largestboats should be on the Bay.

STORM WARNINGS - - Prolonged winds rangingbetween 48 and 63 knots warrant issuance ofStorm Warnings. All boats and oceangoing shipsshould stay in port or seek out a safe anchorageif a Storm Warning is posted.

HURRICANE WARNINGS -- When this warn-ing is issued, winds exceeding 64 knots are ex-pected and every vessel should be securely mooredin port or tucked into one of the many hurricaneholes formerly listed. Moorings should be doubledor strengthened to withstand the extra strains thatwill be placed upon them. If mooring at a dock,allow for increased water heights of as much as12 feet (3.7 meters) above normal mean highwater. Insure that your boat will not ride over topof piles and risk being holed.

Chesapeake Bay has experienced Category I

hurricanes, which have sustained winds of 74-95mph and produce a storm surge 4-5 feet (1.2-1.5meters) above mean sea level. At least once,in 1933, the Bay experienced a Category H hurri-cane, which had sustained winds up to 96-110mph and generated a storm surge of 6-8 feet(1.8-2.4 meters) above mean sea level. Meteoro-logists believe the Bay could encounter a CategoryIII storm with sustained winds of 111-130 mphand a storm surge of 9-12 feet (2.7-3.7 meters).

WEATHER AND BOATING SAFETYThe National Weather Service provides the

marine weather forecasts and warnings to enhancethe enjoyment and safety of the boating commu-nity. The forecast and warning system is notinfallible, however. For example, thunderstormscan produce dangerously strong winds over a smallarea which escape detection by the WeatherService's observation system. Therefore, boatmenmust remain aware of developing weather condi-tions when underway and be able to reach safetywhen conditions become threatening. As men-tioned before, it also is imperative that boatmenknow how Ieir craft will handle under variouswind and wave conditions that might be encoun-tered on the Bay, and heed the weather according-ly. The smart skipper will keep an alert weathereye while he enjoys the Bay's unparalleled boatingresources.

APPENDIX

BOATING SAFETY CLASSES

For additional information on boat handling,weather and boating safety tips, contact the U.S.Coast Guard's Fifth District Office (431 CrawfordStreet, Portsmouth, VA 23705) or the local U.S.Power Squadron and ask about enrollment in theirboating safety classes. A comprehensive boatinghome study course and other boating safetyinformation are available from the Safety Officer,Virginia Commission of Game and Inland Fish-eries, P. O. Box 11104, Richmond, VA 23230.

MARITIME EMERGENCY ANDDISTRESS RADIO PROCEDURES

SPEAK SLOWLY AND CLEARLY

CALL:

1. If you are in DISTRESS (i.e. threatened bygrave and imminent danger) transmit LheInternational Distress Call on either 2182KHz (AM, MAE or SSB), 156.8 MHz (VHF-FM) or Channel 9 for Citizens Band "MAY-DAY (repeated 3 times) this is (your vessel'sname and call sign repeated 3 times)."*

2. If you need INFORMATION or ASSIS-TANCE from the COAST GUARD (otherthan in a DISTRESS), call "Coast Guard" oneither 2182 KHz or 156.8 MHz (the Distressand Calling frequencies). In this situationyou will normally be shifted to a commonworking frequency allowing the DISTRESSfrequencies to remain open.

*The Radiotelephone Alarm Signal (if available)should be transmitted prior to the Distress call forapproximately one minute. The RadiotelephoneAlarm Signal consists of two audio tones, ofdifferent pitch, transmitted alternately. Its pur-pose is to attract the attention of persons onwatch and shall only be used to announce that adistress call or message is about to follow.

IF ABOARD A VESSEL IN TROUBLE - GIVE:

1. WHO you are (your vessel's call sign andname).

2. WHERE you are (your vessel's position inlatitude/longitude or true bearing and dis-tance in nautical miles from a widely knowngeographical point; local names known onlyin the immediate vicinity are confusing).Indicate method of determining your posi-tion: give actual LORAN readings, depth ofwater, radiobeacon bearings, etc. Indicatewhich information you are certain of andwhich position information may be doubtful.

3. WHAT is wrong (nature of distress or diffi-culty).

4. KIND of assistance desired.

5. NUMBER of persons aboard and the conditionof any injured.

6. Present seaworthiness of your vessel.

7. Description of your vessel; length, type,cabin, masts, power, color of hull, super-structure and trim.

8. Your listening frequency and schedule.

9. Emergency equipment: color and typeof flares, lights, number and descriptionof life jackets, flotation cushions andliferafts.

10. End your message with: "This is (yourvessel's name and call sign). Over."

11. Wait for a response. If no answer, repeatyour call. If still no answer, try anotherchannel or frequency.

21

IF OBSERVING ANOTHER VESSEL IN DIFFI-CULTY.- GIVE:

1. Your position, and (if possible) the bearingand distance of the vessel in difficulty.

2. Nature of distress or difficulty.

3. Description of the vessel in distress or diffi-culty.

4. Your intentions, course and speed, etc.

5. Your radio call sign, name of your vessel,listening frequency and schedule.

The Distress Call has absolute priority over allother transmissions and need not to be addressedto any particular station. Any mariner hearing aDistress Call shall immediately cease all trans-missions capable of interferring with the distressmessage and shall continue to listen on the fre-quency which the call was heard.

IF YOU HAVE A MEDICAL CASE SEND:

1. Name of vessel and call sign.

2. Position.

3. Patient's name, age, sex, race and nationality.

4. Nature of problem (symptoms, locations of

pain or injury and whether or not the patientis conscious).

5. Whether or not the patient is ambulatory(able to walk).

6. Patient's temperature and pulse. Difficultbreathing?

7. Whether or not patient is bleeding, and if so,is bleeding controlled?

8. Duration of pain.

9. Previous similar episode (if yes, treatment anddiagnosis).

10. Medicine taken and medicine available.

11. Private physician's name, phone number andhospital address.

12. Description of vessel, intentions and maxi-mum speed possible.

13. Weather: wind direction and speed, waveheight and visibility.

Sources: Mid Atlantic Marine Communications,Fifth Coast Guard District, U.S. Coast Guard,Summer 1979; Marine Communications for theRecreational Boater, SSIC 16772, U.S. CoastGuard, 1979.

r.

222 6

4

Dick Cook