Tornadoes

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Tornadoes Hurricanes
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Targets

• Describe the conditions needed to form a tornado.

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Tornadoes

• Tornadoes hurricanes are cyclones (winds spiral
  inward towards a low pressure center)
• Cyclonic storms dont occur at the equator (no
  Coriolis effect)

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Tornadoes

• Tornado a violent, spinning column of air in
  contact with the ground
• Form in supercells, usually in the spring.
• Tornadoes form when updrafts downdrafts create
  shear, which causes air to rotate.

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Tornadoes
Updrafts cause the spinning column to become
vertical.
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Tornado Facts

• Tornadoes
• Winds up to 300 mph
• Average 700 800/ year in USA
• Diameter of 500 2000 feet
• Travel at 30 mph for 6 miles
• Usually move from SW to NE WHY?
• Measured on the Fujita scale
• F0-F1 weak tornadoes (62 of tornadoes)
• F4-F5 violent (cause 70 of deaths)

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Look Out! Tornadoes!!!

• http//www.youtube.com/watch?vFPfO-yjomig

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Tornadoes

• Tornado watch condition right for a tornado.
• Tornado warning a tornado has been spotted
  nearby.

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Doppler and Weather

• We use the same Doppler principle to monitor
  storms as we do to monitor light arriving from
  distant stars.

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Hurricane Targets

• Explain how hurricanes form.
• Describe the structure of a hurricane.
• Describe hurricane hazards.

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Hurricanes

• Tropical cyclones large, rotating, low-pressure
  storms
• Gain energy from warm, tropical oceans
• Water evaporates, rises then releases heat during
  condensation.

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Hurricanes

• Rising air creates LOW pressure in center of
  cyclone
• Hurricanes last as long as they have a source of
  warm, humid air and a disturbance that lifts the
  air.
• Direction is controlled by wind belts

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Hurricanes

• Stages of Tropical Cyclones
• Tropical wave (
• Tropical Depression (65 120 km/h)
• Hurricane (120 km/h)
• Eye calm center of hurricane
• Eyewall strongest winds heaviest rains around
  the eye.

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Hurricanes

• Classified by wind speed, air pressure and
  potential property damage.
• Saffir-Simpson scale
• Type 1 (74 mph or 120 km/h)
• Type 5 (155 mph or 250 km/h)
• Hurricanes die on land or over cold water.

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Hurricanes

• Strong winds low air pressure cause storm
  surges domes of water pushed onto the coast.
• Up to 6 m (20 feet) high
• Cause the most damage on the coast
• Other hazards include heavy rain, floods and
  tornadoes

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Storm Surge