Thunderstorms and Tornadoes

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Thunderstorms and Tornadoes

• PowerPoint Adapted from CERT Training Materials
• http//www.citizencorps.gov/cert/training_download
  s.shtm

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Objectives

• During this presentation, you will learn
• The warning signs of tornadoes.
• How to prepare in advance for severe
  thunderstorms and tornadoes.
• What actions to take when faced with a severe
  thunderstorm and/or tornado.

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A severe thunderstorm will do one OR more of the
following

• Produce hail at least three-quarters of an inch
  in diameter.
• Create winds of 58 miles per hour or higher.
• Produce a tornado.

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Risks Posed by Thunderstorms

• Lightning
• Hail
• Downbursts and straight-line winds
• Flash floods
• Tornadoes

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Thunderstorm Preparedness

• Understand the risk.
• Learn to make a small target.
• Pay attention to warnings.

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During a Thunderstorm

• Avoid
• Water sources
• The telephone
• The outdoors

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If You Are Outdoors . . .

• Get away from water sources.
• Seek shelter in a substantial building.
• If necessary
• Take shelter in a car or
• Go to low-lying area and make a small target.
• Avoid natural lightning rods.

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In the United States, an average of 300 people
are injured and 80 people are killed each year by
lightning.
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Lightning

• Lightning often strikes outside of heavy rain and
  may occur as far as 10 miles away from any
  rainfall.
• Most lightning deaths and injuries occur when
  people are caught outdoors in the summer months
  during the afternoon and evening.

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IF YOU ARE In a forest. THEN Seek shelter in a
low area under a thick growth of small trees.
IF YOU ARE In an open area. THEN Go to a low
place such as a ravine or valley. Be alert for
flash floods.
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IF YOU ARE on open water. THEN Get to land and
find shelter immediately.
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IF YOU ARE Anywhere you feel your hair stand on
end (which indicates that lightning is about to
strike). THEN Squat low to the ground on the
balls of your feet. Place your hands over your
ears and your head between your knees. Make
yourself the smallest target possible and
minimize your contact with the ground. DO NOT
lie flat on the ground.
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How Lightning Strikes

• Direct.
• Splash strikelightning current jumps from an
  object it initially hit onto someone who sought
  shelter nearby.
• Contact injurylightning strikes an object a
  person is holding.

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How Lightning Strikes

• Step voltagetransmitted along the ground or
  through an object near a person.
• Blunt traumacreated by the shock wave from a
  nearby strike.

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According to a report in the New England Journal
of Medicine, a Canadian jogger was burned when
lightning traveled through the wires of his music
player. The runner had wish-bone shaped burns on
his chest and neck, his eardrums were ruptured
and he also suffered a broken jaw from the jolt.
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• If you were running and came upon the victim from
  the previous slide just after he was struck by
  lightning, what would you do? Would it be safe
  to touch him?

Yes. Lightning strike victims carry no
electrical charge and should be attended to
immediately.
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Lichtenberg pattern
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A tornado is

• A powerful, circular windstorm that may be
  accompanied by winds in excess of 250 miles per
  hour.

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Risks Posed by Tornadoes

• What types of damage do you think a tornado can
  cause? Be specific!

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Risks Posed by Tornadoes

• Tornadoes can
• Rip trees apart.
• Destroy buildings.
• Uproot structures and objects.
• Send debris and glass flying.
• Overturn cars and mobile homes.

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Fujita Wind-Damage Scale

• Measures tornado strength.
• Six levels
• F0 Light damage.
• F1 Moderate damage.
• F2 Considerable damage.
• F3 Severe damage.
• F4 Devastating damage.
• F5 Incredible damage.

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Tornado Preparedness

• Know the risk.
• Identify a safe room.
• Learn the communitys warning system.
• Conduct family tornado drills.

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Tornado Clues
How do you know a tornado is likely?

• High winds.
• Very large hail.

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During a Tornado . . .

• Keep windows and doors closed.
• Go to your safe room.
• Listen to a weather radio.