Tornado

A tornado is a violently rotating column of air which is in contact with both a cumulonimbus cloud or, in rare cases, a cumulus cloud base and the surface of the earth (http://en.wikipedia.org/wiki/Tornado). Tornadoes come in many sizes but are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris (http://en.wikipedia.org/wiki/Tornado). A tornado can have wind speeds up to 110 mph.A tornado can be on the grouind for miles at a time. Tornado very common in the United States.