3. What is severe weather? Weather that poses a danger. The main types of severe weather are:ThunderstormsTornadoesHurricanes

4. Mr. Fetch’s Earth Science Classroom 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.

5. 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 cumulonimbus cloud.

6. If the winds are over 58 mph, the thunderstorm is said to be a SEVERE THUNDERSTORM.

7. How does lightning form? Updrafts and downdrafts of wind and rain cause different parts of a cloud to become electrically charged. -(+) charge at top of cloud - (-) charge at bottom of cloud

8. Every second between a lightning flash and thunder means the storm is 1 mile away. Speed of Light: 186,000 miles/second or 300,000 km/second Speed-of-sound: 1100 ft/sec (330 m/sec) How Far Away is Lightning?

9.  The odds of becoming a lightning victim in the U.S. in any one year is 1 in 700,000.  The odds of being struck in your lifetime is 1 in 3,000.  Man Struck by Lightning Man Struck by Lightning

10.  Talking on the telephone is the leading cause of lightning injuries inside the home  Standing under a tall tree is one of the most dangerous places to take shelter outside  Is Your Car Safe Video? Is Your Car Safe Video?

11. Lightning Facts NO SUCH THING AS HEAT LIGHTNING = FAR AWAY THUNDERSTORM

12.  Thunder  Caused by the rapid expansion and contraction of the air surrounding a lightning bolt.

13. Tornado: A rotating column of air. 1. Wind shear causes air to rotate. 2. The rotating column of air is lifted by updrafts 3. The column of air touches the ground = tornado

19. How are tornados classified?

21. 3 out of every 4 tornadoes in the world happen in the United States A Tornado in Oklahoma once destroyed a whole motel. People later found the motel’s sign in Arkansas The United States have an average of 800 tornadoes every year 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 can occur at any time, but most often between 3pm and 9pm

22. Storm Chasing - your future career? http://www.youtube.com/watch?v=bhGWWY1nCWw&feature=relmfu

23. Hurricanes A tropical area of low pressure that forms over warm water Wind speeds must be higher than 74 mph. Usually given alphabetical names for convenience Slow moving storm: Lasts for days. Pushed by the easterly trade winds.

24. http://www.cbsnews.com/htdocs/natural_disasters/hurricanes/fr amesource_flash.html

25.  Low Pressure Systems  Associated with hurricanes  Strong winds and bad weather  Move Counterclockwise

26. 5 Things a Hurricane needs to Form

27. Progression to a Hurricane DisturbanceDepression Tropical Storm Hurricane

28. Saffir-Simpson Scale is used to measure a hurricane’s intensity

29. Most dangerous part of hurricanes Storm Surge – like what happened with Hurricane Katrina

30.  An abnormal warming of surface water ocean waters in the Eastern Tropical Pacific.  Occurs every 2 - 9 years or so….

31. Droughts in Australia, Indonesia, Pacific NW of US. Heavy storms resulting in flooding in California, Midwest US and Central Europe and Asia.

32.  Happens when the eastern Pacific is unusually cold after being unusually hot for years.