TORRO scale

Scale for rating tornado intensity The TORRO tornado intensity scale (or T-Scale) is a scale measuring tornado intensity between T0 and T11. It was proposed by Terence Meaden of the Tornado and Storm Research Organisation (TORRO), a meteorological organisation in the United Kingdom, as an extension of the Beaufort scale. History and derivation from Beaufort scale The scale was tested from 1972 to 1975 and was made public at a meeting of the Royal Meteorological Society in 1975. The scale sets T0 as the equivalent of 8 on the Beaufort scale and is related to the Beaufort scale (B), up to 12 on the Beaufort scale, by the formula: B = 2 (T + 4) and conversely: T = B/2 - 4 Beaufort scale B 8 10 12 12 12 12 12 12 12 12 12 12 TORRO scale T 0 1 2 3 4 5 6 7 8 9 10 11 The Beaufort scale was first introduced in 1805, and in 1921 quantified. It expresses the wind speed as faster than v in the formula: v = 0.837 B3/2 m/s TORRO scale formula Most UK tornadoes are T6 or below with the strongest known UK tornado estimated as a T9 (the 1666 Lincolnshire tornado). For comparison, the strongest detected winds in a United States tornado (during the 1999 Oklahoma tornado outbreak) would be T11 using t