What is a tornado? A tornado is a violent rotating column of air extending from a thunderstorm to the ground.The most violent tornadoes can produce massive destsruction with wind speeds of 250 mph or more. Damage paths can be more than 1 mile wide and 50 miles wide. The typical tornado moves from southwest to northeast, but they have been known to move in any direction. The average forward speed of a tornado is 30 mph but it may vary from stationary to 70mph.