HURRICANESThe History, Structure,

Development, and Destruction

By S. LaTorre, J. Pannu, P. Nguyen, G. Frederick

Source: http://www.dc.peachnet.edu/~pgore/students/w97/matheson/hpage.htm

What is a hurricane?

Violent cyclonic storm that develops in the tropical region

Wind speeds are > 74 mph

Source: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=680

Rotation and Pressure

In which direction does a hurricane rotate?

COUNTERCLOCKWISE

Is the barometric pressure inside the hurricane high or low?

LOW

When is Hurricane Season?

June 1st throughNovember

31st

What is the role of the National Weather Service during hurricane season?

Provides weather information, such as data from satellites

Responsible for issuing watches and warnings to the media and general public

Watch vs. Warning

What is the difference between a Hurricane Watch and a Hurricane Warning?

Watch – Tropical storm poses a threat to coastal areas with 36 hours

Warning - Tropical storm conditions are expected in a coastal area within 24 hours

What conditions must be present for a hurricane to

develop?

Warm ocean temperatures (>80˚ F) up to 60m deep

Little to no wind shear Low pressure system at

least 5˚ North or South of Equator

Rotation caused by winds Source:

http://lwf.ncdc.noaa.gov/oa/reports/fran/

fran.html

What is the major source of energy fueling a

hurricane?

Heat Energy evaporating from the ocean surface

Source: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/evap.rxml

Hurricane Anatomy

Source: http://hurricanes.noaa.gov/prepare/structure.htm

Another look at the Structure

Source: http://hurricanes.noaa.gov/prepare/structure.htm

Important Terms Tropical Disturbance

Group of thunderstorms in the tropics that are present for at least 24 hours

Tropical Wave lack of circulation, winds <25 mph and

every direction

Tropical Depressionclosed circulation but disorganized, winds

at least 25 mph

Important Terms

Tropical Storm Shower and thunderstorm moves over

closed circulation, winds greater than 39 mph

HurricaneEye is developed, winds > 74 mph

Compare the Following

Source: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hurr/stages/home.rxml

By what two factors is hurricane strength

measured?

Wind Speed

Barometric Pressure

What is the Scale Used to Categorize Hurricanes?

Saffir-Simpson ScaleCategor

yMax Wind

Speed(mph)

Min. Surface Pressure (mb)

Storm Surge m (ft)

1 74-96 > 980 1-1.7 (3-5)

2 97-111 979-965 1.8-2.6 (6-8)

3 112-131 964-945 2.7-3.8 (9-12)

4 132-155 944-920 3.9-5.6 (13-18)

5 > 155 < 920 > 5.7 (>19)Source: http://kids.earth.nasa.gov/archive/hurricane/saffir-simpson.html

What causes the damage in a hurricane?

WindsFloodingStorm Surge

What is a storm surge?

Large wall or dome of water that rushes into the coastline as a result of a hurricane making landfall

To the right are the areas affected by high storm surges

Souce: http://www.wkrg.com/hurricanecenter/surge/SE.jpg

What destroys a hurricane?

Strong vertical winds Cold water Movement over land

FrictionLack of moisture

What are the five costliest hurricanes in the United

States?

1. Hurricane Andrew – 19922. Hurricane Hugo – 19893. Hurricane Fran – 19964. Hurricane Opal – 19955. Hurricane Frederic - 1979

Why the majority of the costliest storms are relatively recent

Damage is a result of development

There are more developed areas and possessions than in the past

Source: http://www.nhc.noaa.gov/1992andrew.html

How has a hurricane affected you personally?

Damage to your house from wind?

Damage from flooding?

Destroyed vacation house?

Damage to family members’ homes?

http://cindi.usgs.gov/cindi/hazard/event/floyd/ncflood/mediums/img023.jpg

Mrs. Parker’s

Old House

Final Water Level

Flooding of Tar River as result of Hurricanes Dennis and Floyd

DocksideTar RiverEstates

Damage to Greenville

Extensive Flooding

Extended Power outages

Flood Related Deaths

Property Damage

US 264 Bridge

Source: http://cindi.usgs.gov/cindi/hazard/event/floyd/ncflood/mediums/img022.jpg

Damage to Greenville

Source: http://www.guc.com/about/floyd.htm

Protection Listen to warnings Take all warnings seriously Follow evacuations Prepare Food and Water for extensive power outages

Source: http://www.dc.peachnet.edu/~pgore/students/w97/matheson/hpage.htm

THE END