Tornadoes are so common in Tornado Alley because of mountains to the west and the Gulf of Mexico to the south, explains Howard Bluestein, professor of meteorology at University of Oklahoma, and veteran storm chaser. In spring, he says, a strong westerly jet stream flows across the Alley, creating instability and a trough of low pressure that draws in warm, moist air from the Gulf. And that's exactly what happens in Tornado Alley. The Fujita scale shows the range of violence of tornadoes. An F-5 tornado produces the most violent winds on earth, approaching speeds of 300 miles per hour.
Tornadoes can last from a few minutes to more than an hour.
A tornado can travel along the ground between a few hundred feet to more than 100 miles. Tornadoes travel along the ground at between 0 and 60 mph. Tornadic thunderstorms produce a couple of other bizarre kinds of wind. They are most common along the Gulf Coast and southeastern states. In the western United States, they occur with cold fall or late winter storms, when you would least expect a tornado to develop.