Emergency and Disaster Information Service.
Atmospheric Optics. What causes tornadoes? Americans know tornadoes like no one else.
The U.S. averages at least 10 times more twisters each year than any other country on Earth, and their intensity is infamous — the worst can be a mile wide, rotate at 300 mph and plow along at 70 mph. Yet despite being target practice for these atmospheric power drills, America's tornado mythos is still cloaked in mystery and misunderstanding. Tornado Videos, Tornadoes, Storm Videos, Storm Chasing, Stormgasm, Hurricanes. NOAA - National Oceanic and Atmospheric Administration.