or F-Scale, standard scale for rating the severity of tornadoes as a measure of the damage they cause, devised in 1951 by the Japanese-American meteorologist Tetsuya (Ted) Fujita (192098). It classifies tornadoes on a hierarchy beginning with category F0, or
(winds of 4072 mph; some damage to chimneys, TV antennas, roof shingles, trees, signs, and windows), which accounts for about 28% of all tornadoes. Category F1, or
(winds of 73112 mph; automobiles overturned, carports destroyed, and trees uprooted), accounts for about 39% of all tornadoes. Category F2, or
(winds of 113-157 mph; roofs blown off homes, sheds and outbuildings demolished, and mobile homes overturned), accounts for about 24% of all tornadoes. Category F3, or
(winds of 158206 mph; exterior walls and roofs blown off homes, metal buildings collapsed or severely damaged, and forests and farmland flattened), accounts for about 6% of all tornadoes. Category F4, or
(winds of 207260 mph; few walls, if any, left standing in well-built homes and large steel and concrete missiles thrown great distances) accounts for about 2% of all tornadoes. Category F5, or
(winds of 261318 mph; homes leveled or carried great distances and schools, motels, and other larger structures have considerable damage with exterior walls and roofs gone), accounts for less than 1% of all tornadoes. Category F6, or
(winds of 319379 mph; automobiles become missiles), accounts for far less than 1% of all tornadoes.