Notes Chapter 5 Lesson 5 Hurricanes
http://www.aoml.noaa.gov/hrd/
What is a Hurricane?
 A violent cyclonic (like a cyclone) storm that develops in
the tropical region.
 Wind speeds are greater than 74 mph.
In which direction does a hurricane rotate?
 Hurricanes rotate counterclockwise.
Is the barometric pressure inside a hurricane high or low?
 The barometric pressure inside a hurricane is low.
When is hurricane season?
 June 1st through November 31st is hurricane season.
What is the role of The National Weather Service during hurricane
season?
 They provide weather information, such as data from satellites.
 They are 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 passes a threat to coastal areas within 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 water.
 The temp needs to be greater than 80°F, up to 60meters deep.
 Little to no wind shear. ( very sharp quick winds)
 Low pressure system at least 5° north and south of the equator.
 Rotation caused by winds.
What is the major source of energy fueling a hurricane?
 Heat energy evaporating from oceans surface.
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/labelanswers.GIF
Comparison of terms
 Tropical Disturbance: Group of storms in the tropics that are
present for at least 24 hours. 1ST
 Tropical wave: The lack of circulation, winds are less than 25 mph.
2ND
 Tropical depression: Closed circulation but disorganized, winds at
least 25 mph. 3RD
 Tropical storm: shower and thunderstorm moves over closed
circulation, winds greater than 39mph. 4TH
 Hurricane: The eye is developed, winds are greater than 74 mph.
5TH
By what two factors is hurricane strength measured?
 Wind speed (measured with an anemometer)
 Barometric pressure (measured with a barometer)
What scale is used to categorize hurricanes?
Saffir- Simpson Scale
Category
1
2
3
4
5
Max-Wind speed (mph)
74-96
97-111
112-131
132-155
>155
What causes damage in a hurricane?
 Winds
 Flooding
 Storm surge
Min. surface area
>980
979-965
964-945
944-920
<920
Storm surge m
1-1.7
1.8-2.6
2.7-3.8
3.9-5.6
>5.7
Storm Surge: Large wall or dome of water that rushes into the coast line as a
result of a hurricane, making landfall.
What destroys a hurricane?
 Strong vertical winds
 Cold water
 Movement over land
- friction
- lack of moisture
What are 5 most costly hurricanes in the U.S.A?
 Hurricane Andrew- 1992
 Hurricane Hugo- 1989
 Hurricane Kran- 1996
 Hurricane Opal- 1995
 Hurricane Fredric- 1979
Why are all of these so recent?
 Damage is a result of development.
 There are more developed areas then the past, in affect.
What are the 5 deadliest Hurricanes in the U.S.A?
 Galveston- 1900
 South Coast Florida- 1928
 Florida Keys- 1919
 New England
 Florida Keys- 1935
Why are these so recent?
 These are so recent because the lack of intelligence to predict and
track and no warnings.
To be continued 