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Severe Weather!!!!!!! Chapter 20.3. What is severe weather?. Weather that poses a danger. What is a thunderstorm?. A storm that produces: 1. Lightning 2. Thunder 3. Heavy Rain and/or flooding 4. Strong winds and possibly hail They last about 15-60 minutes.
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What is severe weather? Weather that poses a danger.
What is a thunderstorm? A storm that produces: 1. Lightning2. Thunder3. Heavy Rain and/or flooding4.Strong winds and possibly hail They last about 15-60 minutes. Mr. Fetch’s Earth Science Classroom
How do thunderstorms form? When warm, moist air is lifted up violently.The air rises up to form a cumulonimbuscloud. Mr. Fetch’s Earth Science Classroom
If the winds are over 58 mph, the thunderstorm is said to be a SEVERETHUNDERSTORM
How does lightning form? Updrafts and downdraftsof wind and rain cause different parts of a cloud to become electrically charged. + + - • (+) charge at top of cloud • (-) charge at bottom of cloud - Mr. Fetch's Earth Science Class
How Far Away is Lightning? • Every secondbetween a lightning flash and thunder means the storm is1 mileaway. • Speed of Light: 186,000 miles/second or 300,000 km/second • Speed-of-sound: 1100 ft/sec (330 m/sec)
Struck By Lightning!!! • The odds of becoming a lightning victim in the U.S. in any one year is 1 in 100,000. • The odds of being struck in your lifetime is 1 in 3,000. • https://www.youtube.com/watch?v=L1HhRAUqFqM • https://www.youtube.com/watch?v=ltK5c60nBHQ
The Safest Place? • Talking on the telephoneis the leading cause of lightning injuriesinside the home • Standing under a tall treeis one of the most dangerous places to take shelter outside https://www.youtube.com/watch?v=bKczulzP5wk
Lightning Facts NO SUCH THING AS HEAT LIGHTNING = FAR AWAY THUNDERSTORM
Thunder • Caused by the rapid expansion and contractionof the air surrounding a lightning bolt.
How does a tornado form? Tornado: A rotating column of air. 1. Wind shearcauses air to rotate.2. The rotating column of air is lifted by updrafts3. The column of air touches the ground = tornado
3 out of every 4 tornadoes in the world happen in the United States Interesting Tornado facts The United States have an average of 800 tornadoes every year A Tornado can occur at any time, but most often between 3pm and 9pm The chances that a tornado is a F5, the highest classification for a tornado on the F-scale, is less than 0.1% A Tornado in Oklahoma once destroyed a whole motel. People later found the motel’s sign in Arkansas
Storm Chasing - your future career? http://www.youtube.com/watch?v=bhGWWY1nCWw&feature=relmfu
Hurricane Animation http://www.cbsnews.com/htdocs/natural_disasters/hurricanes/framesource_flash.html
Saffir-Simpson Scaleis used to measure a hurricane’s intensity
Most dangerous part of hurricanes Storm Surge– like what happened with Hurricane Katrina L