But real tornadoes leave spectators little to cheer about. Most injuries and deaths result from debris hurled by high winds. A tornado is loosely defined as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 miles per hour and greater. Damage paths can be more than one mile wide and nearly 50 miles long.
Tornadoes tend to develop in warm, moist air in advance of eastward-moving cold fronts.
They form from thunderstorms that often produce large hail and extremely strong winds. During late winter and early spring, tornadoes often are associated with strong frontal systems that form in the central U.S. and move east. Large outbreaks of tornadoes may occur with this sort of weather pattern, affecting an immense area that may cover several states. Tornado-producing thunderstorms may form as the dryline moves east during the afternoon hours. Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical.