hurricane case studies. outline north atlantic caribbean gulf of mexico atlantic coast pacific...

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Hurricane Case Studies

Outline

• North Atlantic• Caribbean• Gulf of Mexico• Atlantic Coast• Pacific • Bangladesh

North Atlantic-Caribbean-Gulf of

Mexico• ~4-20 tropical storms/hurricanes each year

• Tend to form in late summer (highest sea temps)

# hurricanes 1931-1980


Mexico


Mexico• 2 main locations for origin

– Western Africa (Cape Verde type)– Caribbean sea

Cape Verde Type

• Start at low pressure systems in western Africa, hit warm water off coast



Cape Verde Type

• Strengthen over warm water, move W/NW because of trade winds, Coriolis force

• Bermuda High: commonly observed pressure system affects path– Small: storms go north– Big: can push storms into Florida, up East Coast

Example: Andrew 1992

• Most destructive (costly) in U.S. history– $30 billion damage

• 3rd strongest in 20th century

Andrew 1992

• Hit S. Florida first– 33 dead– 80,000 buildings destroyed– Trees, cars demolished

• Moved into Gulf of Mexico– Picked up strength with warm water– Hit LA

• 15 dead, significant environmental impacts

– Heavy rain in MS



Time lapse satellite image over 3 days of Andrew moving west to east



Radar image at landfall

Caribbean Sea

• Form in very warm water• Convergence zone of trade winds at equator– Important because convergence means low pressure, tropical depression can form

Example: Mitch 1998

Mitch 1998

• Began in Caribbean Sea• Formed quickly to Category 5 hurricane– Stayed that way for 33 hours

• Headed towards Central America, but stalled– Stayed offshore for 2 days, weakened– Good: didn’t hit coast of Honduras with full force

– Bad: dumped 2-6 ft of rain

Results of Mitch 1998

• Honduras– 6500 fatalities– 20% population homeless– 60% roads/bridges destroyed

• Nicaragua– 3800 fatalities– Lahars from flooding of volcanic lake

• Moved out to Gulf, hit S. Florida on to north of England

• Total: 11,000 fatalities






are needed to see this picture.Flooding and road damage in Nicaragua

Gulf of Mexico Hurricanes

• Along coast: low elevation land

• Along TX coastline, almost 6000 mi2 is less than 20 ft above sea level

• Significant problem for storm surges

Galveston, 1900

• Deadliest natural disaster in U.S. history

• Town on low-lying island in front of bay• Category 4 storm hit; flooded island several ft

• Storm waves, wind destroyed 3600 buildings

• Bridges washed out• Over 7000 fatalities (roughly 1 in 6 residents)

Atlantic Coast - Hugo 1989

• Category 4 storm• 17 ft surge in Ft. Sumter, SC• Moved into NC, WV, OH, PA, NY, Canada as rain

• Only 11 fatalities

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2004 Events

• 15 tropical storms in North Atlantic during the 2004 hurricane season. – Nine of these became hurricanes

• six becoming major hurricanes (Category 3+) • Ivan strongest (Category 5)

2004 Storms• http://www.cnn.com/SPECIALS/2004/hurricanes/interactive/hurricane.paths/index.html

2004 was predicted to be an “active” season with 12-15 tropical storms

FEMA distributed a record $4.85 billion in hurricane relief in 2004

4 hurricanes hit Florida, a record for the state

1 in 5 homes in Florida damaged

117 fatalities in FL alone

Hurricane Charley

• Landfall near Ft. Myers, FL as Cat. 4 storm on Aug 13th

• 16 fatalties, 2 million lost power• Damage likely ~$10 billion• Made 2nd landfall along S.Carolina• Maintained tropical storm force winds through New England (few inches of rain there)

Charley







Hurricane Frances

• Reached Cat. 4 status over Bahamas (Aug 28)

• Hit east coast of Florida as Cat. 2 (Sept5), traveled over state, made 2nd landfall on panhandle as tropical storm

• Traveled north, dropping heavy rains– Quebec got over 8 inches of rain!– Also spawned 117 tornadoes– 23 fatalities

Hurricane Frances



Hurricane Ivan

• Category 5 storm over Grenada, Cayman Islands (Sept 7-9)

• Landfall as Cat. 3 in Alabama• Wacky path - went northeast, then back southwest to cross Florida, Gulf of Mexico on Sept 21 (strengthened back to tropical storm), 2nd landfall in LA on 24th

• Significant rain, flooding (U.S. deaths ~50, more across the Caribbean)

Hurricane Ivan





Hurricane Jeanne

• Formed on Sept. 13, weakened by Sept. 18th, strengthened by 19th and headed out to sea, turned back towards U.S. by 24th

• Significant fatalities in Haiti (over 3000) from flooding and mudslides

• Landfall in U.S. in FL as Cat. 3 on Sept 26th (almost same location as Frances)

• Tracked into mid-Atlantic states• Flooding, 10 fatalities in US

Pacific Coast

• ~15% of events form in Pacific offshore Mexico, Guatemala, El Salvador

• Less hit land than Atlantic hurricanes– Why?

•Trade winds push westward, away from land•Colder water in Pacific reduces potential (California current brings cold water from Alaska)

Pauline, 1997

• Category 4 storm

• Main problem: rain caused flooding and debris flows



Iniki, 1992

• Category 4 storm hit Kauai, HI

• Significant building damage $2 billion



Bangladesh

• Cyclones in this area: Most deadly events

• Densely populated area on low-lying deltas– 35% of country is < 20 ft elevation– In average year, 20% is flooded

• Cyclones are common– ~5/year

Bangladesh

• 1970 ~category 5 storm 400,000 fatalities

• 1991 140,000 fatalities, 10 million homeless

• Population expected to double in next 30 years!

Next Time

• Coastal Hazards

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