Transcript TORNADOES
1 Tornado Nicknames Twisters Funnel cloud Waterspout 2 A tornado is a violently rotating column of air extending from a thunderstorm to the ground 3 Cold air from the north Warm air from the Gulf of Mexico Change in wind direction Increase in wind speed Increasing height Rising air within a thunderstorm 4 What Exactly Is A Tornado? Violently rotating column of air (Vortex) extending from a thunderstorm to the ground How Do They Form? Actually, no one knows for sure! But…We have a pretty good idea… Step 1 Before a t-storm, a change in wind direction and an increase in speed forms an invisible, horizontal spinning effect in the lower atmosphere (at the base of the storm) Step 2 Rising air within the tstorm (updrafts) tilts the rotating air from horizontal to vertical Step 3 Vertical rotation now extends 2-6 miles up into the t-storm. Now a tornado may form and extend from this area of rotation to the ground. Winds can exceed 300 mph!!! Around 1,000 occur on average each year in the U.S. Kill 80, injure 1,500 people each year on average Can have a path up to a mile wide!!! Can occur any time of the year, but peak during the spring (March-June) Occur most frequently in the central U.S. in a region nicknamed “Tornado Alley” Tornado damage is measured by the Fujita Scale. 11 Category Damage Wind F0 light 40–72 mph F1 moderate 73–112 mph F2 significant 113–157 mph F3 severe 158–206 mph F4 devastating 207–260 mph F5 incredible 261–318 mph 12 Where do most tornadoes hit in the United States? In the United States, the area where the tornadoes hit the most is called Tornado Alley. The states which are in the tornado alley are: Danger! Texas Nebraska Colorado Iowa Illinois Indiana Missouri Arkansas Tornadoes! 13 Tornado Watch: A tornado watch is issued when conditions or the weather is right for a tornado to occur Tornado Warning: A tornado warning is issued when a tornado has been seen 14 Where is the safest place to go during a tornado? Safest Places During a Tornado Basement Ditch Shower Inner Hallway Center of Room 15 Number of Tornadoes in Specific Years 180 160 140 120 100 Tornadoes 80 60 40 20 0 1979 1985 1992 2004 16 Songer http://www.pitt.edu/~super1/lecture/lec0761/005.htm A Tornado Develops 1. Name at least one tornado nickname. 2. Name one thing needed for a tornado to occur. 3. What is the name of the scale that measures tornadoes? 4. Which state is not in tornado alley: Texas, California, Nebraska, or Kansas? 5. What is it called when conditions are right for a tornado to occur? 6. Where is the safest place to go during a tornado? 48