Why are tornadoes so dangerous?

Tornadoes, which are intense, funnel-like storms with high winds that typically erupt during thunderstorms, pose a threat to anybody around. These "twisters" are capable of destroying anything in their path, including homes, people, automobiles, trees, animals, and entire cities. Lightweight mobile houses are occasionally tipped over. On April 3, 1974, a violent tornado rushed into Xenia, Ohio, leveling a farmhouse and breaking everything inside, leaving just three fragile objects completely intact: a mirror, a case of eggs, and a box of Christmas decorations! Tornadoes may also perform unusual things like take a train off its tracks and drop it a short distance away!

Every year in the United States, an average of 1,000 tornadoes occur. When a downward flow of cold air from the clouds collides with a rising flow of warm air from the ground, a tornado forms if the atmospheric circumstances are exactly correct. Tornadoes are most common in Tornado Alley, a 10-state region ranging from Texas to Nebraska that also includes Colorado, Iowa, Illinois, Indiana, Missouri, and Arkansas. The majority of weak tornadoes last less than 10 minutes and travel only a small distance. Tornadoes have been reported to last for hours and to travel more than 100 miles (161 kilometers).