Tornadoes are violent rotating columns of air that extend from thunderstorms to the ground. They can have wind speeds over 300 mph and leave damage paths over 50 miles long. Most tornadoes form when warm, moist Gulf air meets cool, dry Canadian air. This clash causes rising and rotating air that can tilt horizontally to vertically, forming a tornado. The strongest tornadoes are rated EF5 on the Fujita scale and can completely destroy well-built homes. To survive a tornado, have an emergency plan and kit ready. Take shelter in a basement, interior room or ditch if a tornado threatens, and stay safe after it passes by avoiding damaged areas.