This region's propensity for tornadoes has earned it the name Tornado Alley. Tornadoes form from thunderstorms, though not all thunderstorms generate tornadoes. An unstable column of warm air rising within cumulus clouds can start to rotate because of changing wind directions at or near the ground. These updrafts alter the air's rotation from horizontal to vertical, creating conditions in which a funnel can develop. If conditions are right and the funnel forms, it can extend to the ground, forming a tornado.
All thunderstorms are capable of producing tornadoes, but detection is still a difficult task.
Weather forecasters can identify the cloud features and conditions that normally precede these storms, and they know where they are most likely to occur. However, predicting the exact time, location, and intensity of tornadoes is still very difficult. Tornadoes threaten areas the size of towns or counties, but hurricanes play themselves out on a much larger stage. These large storms can last for days or weeks and cover thousands of miles of territory. Hurricanes draw their strength from the warm tropical waters of the ocean.