Tornadoes Anonymous A tornado is a violently rotating column of air that extends from a thunderstorm cloud to the earth?s surface. They are sometimes nicknamed twisters because of their shape and because of what they do. The winds in the tornadoes are usually 100mph or less. In +F4's they can exceed 250mph. They usually stay on a track of a few miles or less and are less than 100 yds. wide. For the development of tornadoes there are a few conditions required. An abundant low-level of moisture an