"Tornado Alley" is a nickname given for the central United States. This has to do with a relatively high number of tornadoes there, not necessarily how large or severe they are. While tornadoes have occurred in all fifty states, the more frequent tornadoes spawn in rural and urban areas of the nation’s heartland, especially the southern Great Plains. The Tornado Alley has no official definition regarding to location, but corn-savvy Midwestern states like Iowa and Illinois are sometimes considered in this tornado zone.
The Tornado Alley in the Great Plains isn't very crowded, since it's a "breadbasket" consisting of wheat fields with cities and small towns dotting it. Still, people living in the Tornado Alley should always be ready in case tornadoes form. They are destructive and deadly, which is why it's important to take shelter from them.
Although the Tornado Alley is prone to tornadoes throughout the year, the peak season is in the spring. Specifically, it's from April through June. Spring is the season when there are sudden clashes between warm and cool air masses that are ahead of strong low pressure systems. And usually those low pressure systems allow thunderstorms to develop and contain super cells. But at any time of year, residents in the Great Plains should always stay abreast about them, just in case the twisters arrive.
While there's no real definition for the Tornado Alley regarding to location, it seems much of the tornado activity starts in the Great Plains. The Tornado Alley roughly outlines northern Texas, then much of Oklahoma, Kansas, Nebraska, and into South Dakota. It also includes the eastern fringe of mountain states Colorado and New Mexico. Texas usually gets the most tornadoes, with an average of over one hundred twisters per year.
There are other states that are not quite in the Tornado Alley, but tornadoes are relatively frequent there. Florida is one example, because of the thunderstorms that usually pop up during the daytime, especially in the summer. But those thunderstorms often contain weak tornadoes that usually cause little damage. The Corn Belt states such as Iowa, Illinois, and Indiana have relatively high tornado frequencies as well.
Why does the Tornado Alley have so many tornadoes? In the United States, some people believe tornadoes occur because the dry, cool air from Canada clashes with the warm, moist air from the Gulf of Mexico. On the contrary, many tornadoes come from super cells. A super cell is a rotating thunderstorm, and it has a circulation called the mesocyclone. Super cells are more common in the Great Plains, because tornadoes happen there more often. In addition, super cells may contain lots of lightning, severe hail and flash flooding.
The Tornado Alley is not really densely populated, except in metropolitan areas like Denver, Oklahoma City, Dallas, and Fort Worth. Many cities and towns have storm cellars, in case they become struck by a tornado. There are also public storm shelters available for people who are outside and need to run for cover. Since the Tornado Alley is flat and there aren't many trees and buildings in rural areas, it's an ideal place for storm chasing, especially for meteorology students.
The tornado death tolls in the Tornado Alley are amazingly not high. Even though one-fourth of all the world's significant tornadoes occur in the Tornado Alley, roughly nine percent of related deaths are in the Great Plains. The death tolls are higher in the southeastern United States where tornadoes are less common, and sadly, poverty is more widespread.
The Tornado Alley is only a nickname. It's a preview of where tornadoes occur the most in the United States. Tornadoes do happen virtually anywhere, not just in the U.S. If there's a tornado wherever you are, seek shelter immediately and take cover.