Post on 07-Oct-2020
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Lessons Learned During the 2017-2018 Hurricane Seasons
Lessons Learned During the 2017-2018 Hurricane Seasons
Daniel Brown National Hurricane Center
Daniel Brown National Hurricane Center
WindThat’s What Most Think About
WindThat’s What Most Think About
WaterWhat Most Do Not Consider
WaterWhat Most Do Not Consider
U.S. Atlantic Tropical Cyclone Deaths1963-2012
U.S. Atlantic Tropical Cyclone Deaths1963-2012
Water accounts for about 90% of the
direct deaths
Tornado 3%Wind 8%
Offshore 6%
Other 1%
Surf 6%
Rain27%
Storm Surge49%
Rappaport 2014
2017-18 Hurricane Seasons2017-18 Hurricane Seasons12 Tropical Storms and Hurricanes Affected the U.S. • Five category 5 landfalls
– 4 by Irma in the Caribbean– 1 by Maria in the Caribbean
• Costliest year on record for the US with $265 Billion in damage – 2nd (Harvey), 3rd (Maria) and 5th (Irma) costliest U.S.
individual storms
• Several hundred direct and indirect deaths in the US, but NONE known from storm surge
2017 Records & Other Highlights2017 Records & Other Highlights
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Harvey - $125 Billion Irma - $50 Billion
Maria - $90 BillionUnited States Facts & Figures
• More than $265 billion in damage• Several hundred direct and
indirect deaths• Maria was the strongest hurricane
to make landfall in Puerto Rico since 1928
• Historic rains from Harvey
• TS Alberto struck the U.S. before the official start of the season
• Gordon made landfall along the northern Gulf coast as a strong tropical storm
• Slow-moving Florence produced record setting rainfall in the Carolinas
• Michael (category 4) was the most-intense Florida Panhandle landfall on record
2018 Records & Other Highlights2018 Records & Other Highlights
Florence - $24 Billion Michael - $25 Billion
United States Facts & Figures• Florence produced more than 30 inches of rainfall in North Carolina
breaking a state record set during Floyd (1999) • Michael had the 3rd lowest minimum pressure at landfall in the
continental United States• Michael is the 4th strongest by maximum winds on record in the U.S.• Michael is the strongest U.S. landfalling hurricane since Andrew
(1992)
New GOES-16 Satellite Provided High-Resolution Images of Hurricane Harvey
Hurricane Harvey$125 billion in damage – 68 fatalities
Hurricane Harvey$125 billion in damage – 68 fatalities
• Deadliest hurricane in Texas since 1919
• Storm surge maximum of 8-10 feet near Rockport
• Meandering track after landfall led to historic rainfall – Over 60 inches!
• 57 total tornadoes from Texas to Tennessee
First Issuance of a Storm Surge Warning in the United States
First Issuance of a Storm Surge Warning in the United States
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Storm Surge WarningStorm Surge Warning Quick Transition from Wind/Surgeto Inland Flooding Threat
Quick Transition from Wind/Surgeto Inland Flooding Threat
Hurricane HarveyRecord Setting Rainfall
Hurricane HarveyRecord Setting Rainfall
60.58 inches of rain at Nederland, TX broke the U.S. tropical cyclone rainfall record of 52 inches set in Hawaii in 1950.
Focus on Impacts and HazardsRainfall & Flooding
Focus on Impacts and HazardsRainfall & Flooding
• Potential for extreme rainfall well forecast• NHC began mentioning potential for heavy rainfall a day before Harvey
regenerated in the Gulf (3 days prior to landfall)
Hurricane Irma Hurricane Irma
• Category 4 landfall in the Florida Keys• Category 3 landfall in SW Florida• Significant surge damage in Florida
Keys, and wind impacts across much of the state
Hurricane Irma Hurricane Irma
5 days before landfall
Actual
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Storm Surge Highly Sensitive to Track!Irma 2017
Storm Surge Highly Sensitive to Track!Irma 2017
Observed Track & Simulated Storm Surge
~30 nm
Sanibel Is.
Ft. Myers Beach
~50,000 people with 3+ foot surge
~200,000 people with 3+ foot surge
Forecast Track &Simulated
Storm Surge a Day Before
Landfall
Miami
Miami
Jacksonville, FL Credit: CBS News
Significant Storm Surge Impacts Far from the Center
Significant Storm Surge Impacts Far from the Center
Potential Storm Surge Flooding MapPotential Storm Surge Flooding Map
• Available when a hurricane watch or warning is in effect for the Atlantic and Gulf coasts of the United states (about 48 hours before winds begin on the coast)
Shows height above ground that the
water could reach
Hurricane Irma Hurricane Irma Over Eighty Indirect Deaths in Florida
Most frequent factors: cardiovascular, loss of electricity, vehicle accident, and evacuation
Hurricane Maria Hurricane Maria
• Category 4 landfall in Puerto Rico, but category 5 winds likely occurred at some elevated locations
• Significant storm surge and devastating rain-induced flooding occurred
• Death toll remains highly uncertain
Hurricane Maria Hurricane Maria Consistent NHC Forecasts
Every NHC forecast predicted landfall
in Puerto Rico.
All but the first predicted major hurricane intensity
at landfall.
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Hurricane Florence Hurricane Florence
• Category 4 over the Atlantic• Category 1 landfall in North Carolina• Significant surge damage in portions of
eastern North Carolina• Storm slowed producing more than
30 inches of rains in parts of North Carolina
Hurricane Florence Unexpected Strengthening
Hurricane Florence Unexpected Strengthening
Category 1 to 4 in 36 hours – no model suggested this would occur
Hurricane Florence Intensity Forecast Difficulty
Hurricane Florence Intensity Forecast Difficulty
NHC missed period of rapid strengthening and then over-forecast intensity near landfall
NHC Intensity Forecasts – Florence (2018)
Hurricane Florence In-house 6- and 7-day Forecasts
Hurricane Florence In-house 6- and 7-day Forecasts
Some long-range forecasts suggested Florence would re-curve over the central Atlantic
NHC Experimental 6- and 7-day forecasts
Track Forecast Success During Florence’s Approach to the U.S.Track Forecast Success During
Florence’s Approach to the U.S.
Some long-range forecasts suggested Florence would re-curve over the central Atlantic
Record Setting Rainfall Predicted Record Setting Rainfall Predicted
5-day Rainfall Forecast
Forecast vs. Observed Rainfall
Observed 5-day Total
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Weather Prediction CenterExcessive Rainfall Graphic
Weather Prediction CenterExcessive Rainfall Graphic
Highlights Risk of Flash Flooding
More from Greg Carbin later today
Hurricane Michael Hurricane Michael
Photo courtesy of Getty Images
Photo courtesy of Georgia National Guard
Pine Tree Damage in AndrewHurricane Michael
Hurricane Andrew
Hurricane Andrew
Comparing Michael and Andrew (1992) Tree Damage
Comparing Michael and Andrew (1992) Tree Damage
Tracking Hurricane Michael Tracking Hurricane Michael
Intensity Forecasting StrugglesNHC Forecasts Major Hurricane but Too Low
Intensity Forecasting StrugglesNHC Forecasts Major Hurricane but Too Low
NHC forecast above guidance but not
high enough
Storm Surge Products Provide“Reasonable Worse-Case” Scenario
Storm Surge Products Provide“Reasonable Worse-Case” Scenario
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“Officials Warn it Could be Storm of the Century”
“Officials Warn it Could be Storm of the Century”
“Life-threatening wind, surge closing in”
Track Forecasts Very Consistent in Showing Threat to the Florida Panhandle
Track Forecasts Very Consistent in Showing Threat to the Florida Panhandle
Improvements in Track Forecasting3-day Forecasts in 1990
Improvements in Track Forecasting3-day Forecasts in 1990
1992
Improvements in Track Forecasting3-day Forecasts Today
Improvements in Track Forecasting3-day Forecasts Today
1992
Shrinking Forecast ConeMeans More Impacts Outside Cone
Shrinking Forecast ConeMeans More Impacts Outside Cone
Challenge Communicating RiskChallenge Communicating Risk
• “This is just a CAT 1 hurricane”• “It has never flooded here before”• “I’ve been through a CAT 3, nothing happened here”• “I saw the new forecast, that GFS thing says it won’t
come here, phew!”• “This is the same surge forecast as the last one and I
didn’t flood then”• “We are going to evacuate for all CAT1 hurricanes from
now on”• “Ah great, I have a GIS map. Finally something accurate”• “We just had our 100 year storm last year”
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Key Messages and Social MediaKey Messages and Social Media
Use of Twitter, Facebook, and Facebook Live to provide live
storm updates
Focus on Hazards & ImpactsNot Track or Category
Focus on Hazards & ImpactsNot Track or Category
• Every storm is different• Must remain focused on
water & wind hazards• NHC probabilistic products
help decision makers • Significant impacts occur
far from the center –outside the cone
• Share only reliable sources of information
Focus on Hazards & ImpactsNot Track or Category
Focus on Hazards & ImpactsNot Track or Category
Hurricane Preparedness Week Actionable Daily Themes
Hurricane Preparedness Week Actionable Daily Themes
• Sunday – Determine Your Risk• Monday – Develop an Evacuation Plan• Tuesday – Assemble Disaster Supplies• Wednesday – Get an Insurance Checkup • Thursday – Strengthen Your Home• Friday –Help Your Neighbor • Saturday – Complete your written hurricane plan
Weather Ready NationWeather Ready NationAddress the “last mile” - connects forecasts to critical
emergency management decisions & individual preparedness
The Past Accurate, consistent forecast with decision
support
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Weather Ready NationHelp Us!
Weather Ready NationHelp Us!
Questions?Questions?