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Tornadoes: The Most Deadly Natural Occurrence Text Only Page 2
knows how many tornadoes ravish the land yearly because many of these storms are in unpopulated areas and might not be reported. About 700 tornadoes are reported annually in the United States since the 1950's.
The Story Of A Tornado
Tornadoes mostly develop in the mid west and the states that border the Gulf of Mexico (Texas, Oklahoma, Kansas, Nebraska, Iowa, Missouri, Arkansas, Louisiana, Mississippi and Alabama.). This is because of the warm, moist, humid air rising north from the Gulf of Mexico and the Caribbean from the south, which combines with the cold, dry air of Canada and the North.
Scientists do not know exactly why tornadoes form, but they do know that most tornadoes form along a front (boundary) between cool, dry air and warm, humid air. A narrow zone of cumulonimbus (thunderstorm) cloud develops along the front. This zone of clouds, called a squall line, produces violent weather that, in time, forms a tornado.
The violent weather produced by a squall line results when a mass of warm, humid air rises extremely rapidly. As the air rises, more warm air rushes in to replace it. The in rushing air also rises and, in some cases, begins to rotate. The rotating air then forms into a tornado.
Tornadoes mostly begin on a hot, humid day in the afternoon or early evening. To begin with large thunderclouds enter the sky and thunder begins to rumble. A cloud near by will become dark and dense before the rounded bottom begins to twist. One of the twisting clouds then forms a funnel cloud that gradually extends downwards towards the earth. Heavy rain and some hail starts to fall. Also, lightning begins to flash. A hissing sound begins as the funnel cloud gets closer to earth. If the funnel touches the ground, it stirs up all the earth and debris in it's way. The hissing becomes a loud roar.
The violent rotating winds blow down everything in their path. Also a tornado can demolish any thing from a small house to reinforced buildings with its explosive forces, depending on it's size.
