Georgia Emergency Management Agency

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Georgia Emergency Management Agency
Hurricanes Back to Basics and Georgias Risk
Chris WalshHurricane Program
ManagerPlanning SectionOperations
DivisionOctober 28, 2008
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• This is why we prepare

Hurricane Rita (2005) compared to Georgia
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Disasters in Georgia
Georgias Federally Declared Disasters from 1953
2008

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Return Interval for Tropical Cyclone Disasters 1
per 8 years
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Hurricane Return Intervals
Last Hurricane landfall in Georgia Category 1
David (1979)
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Major Hurricanes within 65 nmi of Coastal
Georgia 1800-1899
1893
1885
1896
1893
1804
1854
1824
1898
1813
Year Category - Landfall 1804 Est. Cat. 4
Glynn 1813 Est. Cat. 3 Camden 1824 Est.
Cat. 3 Glynn 1854 Cat. 3 Liberty/Bryan 1885
Cat. 3 Offshore 1893 Cat. 3
Bryan/Chatham 1893 Cat. 3 Offshore 1896 Cat
.3 Cedar Key, Fl. 1898 Cat .4 Camden
1896
Graphic by Al Sandrik NWS WFO Jacksonville
1885
1824
1813
1898
1893
1804
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Georgias Hurricane History
Coastal Impacts

• 1950 1999 1 named storm (Hurricane David,
  1979)
• 1900 1949 4 named storms (1911, 1928, 1940 and
  1947)
• 1851 1899 14 named storms and 3 major
  hurricanes
• 1898 Category 4 Tybee Island 19 storm surge
• 1893 Category 3 Approximately 1500 2500
  fatalities
• 1854 Category 3
• 1800 1850 3 major hurricanes
• 1824 Category 3
• 1813 Category 3 St. Marys Island 17 storm
  surge
• 1804 Category 4 Approximately 500 fatalities

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Tropical Cyclone Classifications

• Tropical Depression
• (38 mph or less)
• Tropical Storm
• (39 73 mph)
• Hurricane
• (74 mph and greater)

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Saffir-Simpson Scale
Catastrophic Category 5Strongest winds gt 155
mph Extreme Category 4Winds 131-155
mph Extensive Category 3Winds 111-130
mph Moderate Category 2Winds 96-110
mph Minimal Category 1Winds 74-95 mph
Saffir-Simpson Hurricane Scale
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Hurricane Hazards

• There are four principal hazards associated with
  hurricanes
• Wind
• Storm Surge
• Tornadoes
• Inland Flooding

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Hurricane Winds

• Winds within a hurricane are strongest to the
  right of the track
• Hurricane force winds can be carried very far
  inland Hurricane Hugo (1989) produced wind
  gusts of 100 mph in Charlotte, NC which is 175
  miles from the coast
• Winds in a hurricane decay rapidly roughly 50
  weaker in 12 hours after landfall

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Hurricane Ivan Sep. 15, 8AM
430 miles
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Hurricane Ivan Sep. 16, 2PM
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Wind Threat to Georgia

• The National Oceanic and Atmospheric
  Administration (NOAA) has conducted hurricane
  modeling and produced wind threat maps known as
  Maximum Envelope of Wind (MEOW) maps
• These maps are available on the National
  Hurricane Center (NHC) website

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Hurricane Charley (2004) by Ultimate Chase.com
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Tornadoes from Hurricanes

• Nearly 60 of hurricanes that made landfall (1948
  to 1986) spawned at least one tornado
• In general, tornadoes associated with hurricanes
  are less intense than those that occur in the
  Great Plains
• Hurricanes have the potential to produce
  significant tornado outbreaks
• Hurricane Ivan (2004) produced 119 tornadoes 48
  F0, 52 F1, 18 F2, 1 F3

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Tornadoes and Hurricanes

• Tornadoes are more likely in the right front
  quadrant

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Tornadoes and Hurricanes
2005 Hurricane Season
At least 221 tornadoes occurred in association
with the tropical cyclones (Arlene, Cindy,
Dennis, Emily, Katrina, Rita, Tammy, and Wilma)
that affected the United States.
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Inland Flooding

• Inland Flooding is the 1 cause of casualties
  associated with Hurricanes
• This threat occurs from all magnitudes of
  tropical cyclones Tropical Storms Category 5
• Tropical Storm Alberto (1994) was the costliest
  natural disaster in Georgias history
• Estimated cost of 750 million
• 57 or 159 counties flooded

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Inland Flooding Impacts
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August 17 29, 2008
4275 Sites
FL Maximum 27.65
GA Maximum 27.50
Melbourne, FL
Thomasville, GA
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Tropical Cyclone Deaths

• Pre-Katrina

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Storm Surge

• Storm Surge is the 1 cause of damage in coastal
  areas
• Katrina Over 1,300 deaths attributed to storm
  surge and flooding
• Planning Assumption Due to Georgias coastal
  basin characteristics, a major hurricane making
  landfall on the Georgia coast has the potential
  to impact the entire coast causing a catastrophic
  disaster

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Storm Surge

• The Georgia Coast has the potential to have the
  second highest storm surge possible along the
  Atlantic Coast
• The Georgia Coast is one of the most vulnerable
  storm surge areas in the United States with
  features similar to coastal Mississippi during
  Katrina. Al Sandrik, Warning Coordination
  Meteorologist, Jacksonville NWS
• Highest storm surge ever recorded of 33 feet in
  Bay St. Louis, MS from Hurricane Katrina (2005)

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Storm Surge Planning

• Computer modeling of hurricanes by NOAA and the
  NHC has produced Maximum Envelope of Water (MEOW)
  maps for storm surge
• MEOW maps depict the maximum extent inland for
  surge by category of hurricane
• The Sea, Lake, and Overland Surge from Hurricanes
  (SLOSH) model is the premier surge model used by
  the NHC

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Sea, Lake and Overland Surge from Hurricanes
(SLOSH)
28 feet
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Hurricane Katrina (2005) by Ultimate Chase.com
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Hurricane Sierra
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• Any Questions?