Thunderstorms and Tornadoes PowerPoint Adapted from CERT Training Materials:

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.

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.

Risks Posed by Thunderstorms Lightning Hail Downbursts and straight-line winds Flash floods Tornadoes

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

During a Thunderstorm Avoid: Water sources The telephone The outdoors

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.

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

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.

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.

IF YOU ARE: on open water. THEN: Get to land and find shelter immediately.

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.

How Lightning Strikes Direct. Splash strike—lightning current jumps from an object it initially hit onto someone who sought shelter nearby. Contact injury—lightning strikes an object a person is holding.

How Lightning Strikes Step voltage—transmitted along the ground or through an object near a person. Blunt trauma—created by the shock wave from a nearby strike.

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.

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.

Lichtenberg pattern

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

Risks Posed by Tornadoes What types of damage do you think a tornado can cause? Be specific!

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.

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.

Tornado Preparedness Know the risk. Identify a “safe” room. Learn the community’s warning system. Conduct family tornado drills.

Tornado Clues High winds. Very large hail. How do you know a tornado is likely?

During a Tornado... Keep windows and doors closed. Go to your “safe” room. Listen to a weather radio.