It's that time of year again, when a sunny day can turn stormy in an instant! Here in the Ohio, Big Sandy and Kanawha Valleys, we don't have to worry much about tornadoes. On average we have one tornado touch-down in the Tri-State every couple of years. 2009 was a very active year with many severe thunderstorms, tornado warnings and about two tornadoes actually touched down.
There's an area to our west which receives more tornadoes than in any other part on Earth and it's known as "Tornado Alley."
Although no U.S. State is entirely free of tornadoes, they are most frequent in the plains between the Rocky and Appalachian Mountains. According to the Storm Prediction Center, Texas reports more tornadoes than any other state, though this state's very large land area should be taken into account. Kansas and Oklahoma are second and third respectively for sheer number of tornadoes reported but report more per land area than Texas. However, the density of tornado occurrences in northern Texas is comparable to Oklahoma and Kansas. Florida also reports a high number and density of tornado occurrences, though only rarely do tornadoes there approach the strength of those that sometimes strike the southern plains.
Although Tornado Alley is considered to be in the areas of the Central U.S. no official definition of the term has actually been produced by the National Weather Service. "Tornado Alley" is a term created by the media to refer to areas that have greater numbers of tornadoes. 90% of tornadoes hit this region of the U.S because cold, dry air from Canada and the Rocky Mountains meets warm, moist air from the Guld of Mexico and hot, dry air from the desert southwest, which combines with atmospheric instability to produce intense thunderstorms.