Since tornadoes very seldom pass over wind equipment, their wind speeds are estimated by examining damage patterns. The most commonly used scale of tornado intensity was devised by Theodore Fujita. Breaks branches off trees. Some damage to chimneys. 73 to 112 MPH Moderate damage.
Peels surface off roofs.
Attached garages may be destroyed. Mobile homes may be overturned. 113 to 157 MPH Considerable damage. Roofs torn off frame houses. Mobile homes demolished.