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A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud. It is spawned by a thunderstorm (or sometimes as a result of a hurricane) and produced when cool air overrides a layer of warm air, forcing the warm air to rise rapidly. Tornadoes can cause a lot of damage and even deaths. The damage from a tornado is a result of the high wind velocity and wind-blown debris. Tornado season is generally March through August, although tornadoes can occur at any time of year. They tend to occur in the afternoons and evenings: over 80 percent of all tornadoes strike between noon and midnight. From 1950-1995 the total number of tornadoes in Michigan was 722, with an average of 5 deaths and 3,217 injuries (70 a year average) resulting from the storm a year. Tornadoes are rated on a scale called the Fujita Scale. The storms are labeled with the letter F and then a number 0-6. The Fujita Scale is used to rate the intensity of a tornado by examining the damage caused by the tornado after it has passed over a man-made structure. The table below shows the ratings for a tornado with the Fujita Scale. The Fujita Scale F-Scale Number Intensity Phrase Wind Speed Type of Damage Done F0 Gale tornado 40-72 mph Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards. F1 Moderate tornado 73-112 mph The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed. F2 Significant tornado 113-157 mph Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated. F3 Severe tornado 158-206 mph Roof and some walls torn off well constructed houses; trains overturned; m... ... middle of paper ... ...erfall or rushing air at first, but turning into a roar as it comes closer. The sound of a tornado has been likened to that of both railroad trains and jets. · Debris dropping from the sky. · An obvious "funnel-shaped" cloud that is rotating, or debris such as branches or leaves being pulled upwards, even if no funnel cloud is visible. If you see a tornado and it is not moving to the right or to the left relative to trees or power poles in the distance, it may be moving towards you! Remember that although tornadoes usually move from southwest to northeast, they also move towards the east, the southeast, the north, and even northwest. Encourage your family members to plan for their own safety in many different locations. It is important to make decisions about the safest places well BEFORE you ever have to go to them. BIBLIOGRAPHY 1. 2. 3. Encyclopedia Britanica 4. Earth Science- Tenth Edition 5.

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