A tornado is one of the most mesmerizing, yet one of the most feared natural disasters. These giant rotating columns of air normally measure between 250 feet and two miles across, and travel between 110 and 300 miles per hour. They can decimate a town in a matter of minutes. These powerful cyclones, also known as "twisters," develop from warm, moist air mixing with cool, dry air, creating a vacuum effect.
Tornadoes have been spotted on every continent except Antarctica, but the most heavily hit area in the world is "Tornado Alley," which is in the central states. "Tornado Alley" is comprised of Texas, Kansas, Oklahoma, Florida, Nebraska, Iowa, Illinois, Mississipi, and Alabama. Based on the high numbers of tornadoes, building codes often are more strict in this part of the country, and require storm cellars in residential areas.