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 and unstable atmosphere is required not only for the tornado, but for a thunderstorm also....
uprooted light object missiles generated. F3Wind: 158-206mphSevere Damage :Roofs and some walls torn off well constructed houses trains overturned most trees in forecast uprooted heavy cars lifted off the ground and thrown weak pavement blown off the roads. F4Wind: 207-260mphDevastating Damage: Well constructed houses leveled structures with weak foundations blown off the distance cars thrown and disintegrated trees in forest uprooted and carried some distance awayF5Wind: 261-318mphIncredible Damage : Strong frame houses lifted off foundations and carried considerable distance to disintegrate automobile sized missiles fly through the air in excess of 300 feet trees debarked incredible phenomena will occur.