general science 1 spring ‘08. hurricane season occurs between june 1-november 30 threatens the...
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General Science 1Spring ‘08
Hurricane SeasonOccurs between June 1-November 30Threatens the Gulf Coast of the US, Eastern
Coast, Mexico, Central America and Caribbean“hurricane” in the Atlantic ocean“typhoon” in Asia“cyclone” in Australia
Hurricane Terms
Tropical depression Rita
Tropical storm Boris
A tropical cyclone (low pressure area) that occurs in the North Atlantic.
Tropical depression- winds less than 39 mph
Tropical storm- Winds between 39-74 mph and given a name
Hurricane- winds 75mph or greater
Characteristics of HurricanesTropical- form in tropical areas near equator
with water temps. near 80oF.Cyclonic- winds swirl around a central eye
Counter clock wise in northern hemisphereClock wise in southern hemisphere
Low-pressure systems- eye is always a very low pressure
Parts of a hurricaneEye- low pressure center, calm areaEye wall- area around the eye, fastest, most
violent windsRain bands- bands of thunderstorms
circulating outward from the eye; feeds the storm
Begin off west coast of Africa as thunderstorms
They move east over warm, tropical waters
Warm, moist air over the ocean rises quickly, condenses and forms clouds
Rising air is replaced by warm, humid air from below.
Cycle continues, drawing warm air inward.
Circulation and wind speeds increase
Air moves from areas of high to low pressure, so more air is pulled inward, feeding the hurricane
It can take several hours or days for a hurricane to form
Size and LocationHurricanes vary widely in sizeCan spread out over hundred to thousands of
miles
Hurricane Danny (left) in 1997 and Hurricane Fran in 1996 show the
variability in hurricane size
Watches and WarningsTropical Storm Watch- 39-75 mph winds
possible within 36 hoursTropical Storm Warning- conditions likely
within 24 hrsHurricane watch- hurricane conditions
possible within 36 hoursHurricane warning- hurricane within 24 hrs
DamageCaused by:
Rain (up t0 40 inches!)Flooding (due to the rain)Winds (75 mph or greater)Storm surge
wall of water that comes in front of a hurricane Created by wind Increases flooding/erosion
tornadoes
Damage Depends on 3 Things1. Strength of storm2. If it hits land3. Right or left side of eye strikes an area-
right is worse (winds/rain stronger)
Saffir-Simpson Scale
Hurricane Isabella as a Cat. 1 on 9/19/05
Category 174-95 mph windsSome floodingLittle to no damage
Category 296-110 mph windsTrees downRoof damageflooding
Saffir-Simpson Scale
Category 3111-130 mph windsStructural damage to
homesMobile homes
destroyedSevere floodingLoss of life
Category 4131-154 mph windsSever flooding inlandMajor structural
damage (roofs ripped off)
Loss of life
Saffir-Simpson Scale
Hurricane Katrina as a Category 5 on August 28,
2005. One day before making
landfall on the Gulf Coastwww.hurricanekatrina.com
Hurricane Andrew (1992)
Category 5Greater than 155 mph
winds!Severe flooding further
inlandSevere damage to most
wooden structuresLoss of life
Money to RebuildFEMA- Federal Emergency Management Agency
Created in 1979Headquarters in Washington, DCA small agency with only 2,600 full-time
workers, and nearly 4,000 other workers called Disaster Assistance Employees. These workers are on stand-by to respond after
a disaster happens.
Became part of the Department of Homeland Security on March 1, 2003.
In charge of helping people before and after a disaster.
Called in to help when the President declares a disaster.
Disasters are “declared” after hurricanes, tornadoes, floods, earthquakes or other similar events strike a community.
Hurricane KatrinaOne of the five deadliest hurricanes in US
history.6th strongest Atlantic hurricane ever
recorded.3rd strongest hurricane on record to make
landfall.Formed on August 23, 2005.
Hurricane KatrinaMost severe damage in New Orleans, LA.At least 1,836 people lost their lives.Estimated $81.2 billion in damage (2005)
making it the costliest natural disaster in US history.
Political AftermathPoor response by FEMABut the National Hurricane Center and the
National Weather Service were widely commended for accurate forecasts and abundant lead time.