In terms of tornado frequency per square miles, Kansas ranks number one and Oklahoma, number 2. Texas reports more tornadoes overall, but its much larger area accounts for this. Every state in the U.S. experiences tornadoes, but the area known as “Tornado Alley” is a high-frequency region. It is not full defined, but is stretches from the Rockies to the Appalachians and up into the Canadian plains as well. In Tornado Alley, warm, humid air from the equator comes into contact with cool, dry air from Canada, creating an ideal tornado nursery, where vicious and dangerous twister form in thunderstorms. Tornadoes occur in virtually every country in the world with some having frequency similar to the Alley’s.