Download Hurricanes and Tornadoes - Hewlett

Hurricanes and Tornadoes
Hurricanes- are cyclones that have winds
exceeding 115 km/hr(75 mi/hr) and an average
diameter of 600 km; these winds surround an area
of extremely low pressure
 Hurricanes form over tropical oceans
 Hurricanes are heat engines that are fueled by
the heat stored in the water vapor.
 Hurricane season is late summer and early
fall, when ocean water is at its highest
temperature.
 Hurricanes do not have fronts
 Eye of the hurricane is the center and it’s very
calm.
Hurricanes lose strength
1. If they move onto land, cutting off the
storms source of warm, moist air.
2. If they move north into cooler ocean
waters that cannot supply warm, moist
air.
$$The Storm Surge of a Hurricane causes the
most damage.
Storm Surge- forms when the hurricane piles up
water along the shore and then blows it inland
 In 1991 a Tropical Cyclone produced a 20 ft.
storm surge in Bangladesh killing 139,000
people and leaving over 9 million homeless.
Tornado- a narrow, funnel-shaped column of
spiraling winds that extends downwards from a
cumulonimbus cloud and touches the ground
 Strongest winds are about 360-500km/hr (300
mi/hr)
 Pressure inside the tornado is extremely low.
 Occur near cold fronts.
 Are usually less than a mile wide and only last
a few minutes.
Formation of Tornadoes
1. Warm, moist air from the Gulf of Mexico
moves Northward.
2. Cold, dry air from Canada moves
Southward.
3. These two air masses meet and form a
Cold front.
4. Thunderstorms are produced at a Cold
front.
5. These thunderstorms could spawn a
tornado.