Tornadoes are the most destructive of all weather-related events. On average, a tornado's path is 4 miles long and 400 yards wide but can be as long as 100 miles and as much as a mile wide. Tornadoes can reach heights of 60,000 feet. The average tornado travels at a speed of 25 to 40 mph., but tornadoes can reach speeds up to 70 mph. Winds inside a tornado can swirl at close to 300 mph.
Most tornadoes move from southwest to northeast.
Most tornadoes in the Northern Hemisphere rotate in a counter-clockwise direction. Most tornadoes in the Southern Hemisphere rotate in a clockwise direction. Building damage during a tornado happens when high winds cause a buildup of pressure on building surfaces. This pressure is related to wind velocity squared. About 800 tornadoes touch down in the United States each year.