Unformatted text preview: Do Tornados Really Sound Like Freight Trains?? Freight http://www.interaxs.net/pub/hgr/xenia_tornado What What do you think after listening to the Xenia Tornado of April 3, 1974? Xenia Winds can exceed 300 mph!!! Around 1,000 occur on average each year in the Around U.S. U.S. Kill 80, injure 1,500 people each year on Kill average average Can have a path up to a mile wide!!! Can occur any time of the year, but peak during Can the spring (March-June) the Occur most frequently in the central U.S. in a Occur region nicknamed “Tornado Alley” region What Exactly Is A Tornado? What Violently Violently rotating column of air (Vortex) extending from a thunderstorm to the ground ground How Do They Form? How Actually, But…We no one knows for sure! have a pretty good idea… Step 1 Step Before 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) base Step 2 Step Rising air within the tstorm (updrafts) tilts storm the rotating air from horizontal to vertical horizontal Step 3 Step Vertical 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. ground. Convection Demo Convection Same Same basic principle behind a tornado vortex (funnel; column of fire in this case) vortex Warm air moves up the vortex (updraft) Warm (updraft) Cools and sinks as it funnels out of the top Cools (downdraft) (downdraft) The more air drawn in = faster and tighter The spin spin This is called a convection cycle This convection How Strong Are Tornados? How Strength is measured by the Fujita Scale... F0 = weakest, F5 = Strongest Are Most Tornados Strong? Are All All tornados are potentially deadly, but most are actually relatively weak (74%)…! are Only 1% of all tornados fall in the F4 – F5 Only range range What’s Up With Xenia, OH? What’s Xenia Xenia has been the target of several major tornados down through the years… tornados recent: Sept. 2000 Notable: April 3, 1974 Most Most Most Most Sept. 2000 Damage Sept. Where do you think this Tornado ranked on the Fujita Scale? April 3, 1974 Tornado April April 3, 1974 Damage April Where do you think this tornado ranked on the Fujita Scale? Answers Answers Sept. Sept. 2000 = F3-F4 F3-F4 (Severe/Devastating Damage; Winds of 200-260 mph) 200-260 1974 = F5 F5 (Incredible Damage; Winds of 260-300+ mph!!!) mph!!!) April April Quick Review Quick Are most tornados strong or weak? Which would cause more damage, an F1 or an Which F5 tornado? F5 During which season do most tornados occur in During the U.S.? the What is the nickname of the region in the U.S. What where many tornados occur? where What is used to classify the intensity of What tornados? tornados? Bonus**: How do experts think tornados form? ...
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- Spring '08
- 1%, Fujita scale, 74%, 6 miles