The Fujita scale is used to rate the severity of tornadoes as a measure of the damage they cause. The scale was devised in 1971 by the Japanese-American meteorologist Tetsuya (Ted) Fujita. It classifies tornadoes using the following scale.

F0 - light winds of 64 to 116 km/hr; some damage to chimneys, TV antennas, roof shingles, trees, signs, and windows and accounts for about 28 percent of all tornadoes.

F1 - moderate winds of 117 to 180 km/hr; automobiles overturned, carports destroyed, and trees uprooted. F1 tornadoes account for about 39 percent of all tornadoes.

F2 - considerable winds of 181 to 252 km/hr; roofs blown off homes, sheds and outbuildings demolished, and mobile homes overturned. F2 tornadoes account for about 24 percent of all tornadoes.

F3 - severe winds of 253 to 330 km/hr; exterior walls and roofs blown off homes, metal buildings collapsed or severely damaged, and forests and farmland flattened. F2 tornadoes account for about six percent of all tornadoes.

F4 - devastating winds of 331 to 417 km/hr; few walls, if any, left standing in well-built homes; large steel and concrete missiles thrown great distances. F4 tornadoes account for about two percent of all tornadoes.

F5 - incredible winds of 418 to 509 km/hr; homes leveled or carried great distances. F5 tornadoes can cause tremendous damage to large structures such as schools and motels and can tear off exterior walls and roofs. Tornadoes of this magnitude account for less than one percent of all tornadoes and have never been officially recorded in Canada. However, recent research suggests that as many as two may have occurred in Saskatchewan, regardless, F5 tornadoes are possible in Canada every summer.

Fujita Scale Rating the Severity of Tornadoes

Fujita Scale
Rating the Severity of Tornadoes