The higher the number, the more severe the tornado. Tornadoes occur all over the world, but most of them happen in the United States. Of the U.S. tornadoes, most of them happen in an area called Tornado Alley. The flat lands of Texas, Oklahoma, Kansas, Nebraska, Iowa and Missouri have many tornadoes each year. Other states have tornadoes, too.
Tornado season begins in spring and lasts through summer.
The states in Tornado Alley can see 50 or more tornadoes a week during tornado season. Some of these tornadoes are big, but most are small. Many people watch for tornadoes during tornado season. Meteorologists, scientists who study weather, watch weather radar for possible tornadoes. Radar is a device that tracks storms and weather.