TORRO scale

The TORRO tornado intensity scale, also called the T-Scale, is a way to measure how strong tornadoes are. It ranges from T0 to T11, with each number showing a different level of power.

This scale was created by Terence Meaden, who worked with the Tornado and Storm Research Organisation (TORRO). TORRO is a weather group based in the United Kingdom.

The TORRO scale was made to add more detail to the older Beaufort scale. By using the TORRO scale, scientists and weather experts can better understand and talk about how intense tornadoes are. This helps people know how dangerous a tornado might be and what kind of damage it could cause.

History and derivation from Beaufort scale

The TORRO scale was tested from 1972 to 1975 and was shown to the public in 1975 at a meeting of the Royal Meteorological Society. This scale starts at T0, which matches level 8 on the Beaufort scale. It links to the Beaufort scale using a simple math rule.

The Beaufort scale began in 1805 and was made exact in 1921. It describes wind speed using a formula that connects the wind speed to the number on the scale.

TORRO scale formula

Most tornadoes in the United Kingdom are T6 or weaker. The strongest tornado ever recorded in the United Kingdom was a T9. This happened in Lincolnshire in 1666.

The strongest winds ever measured in a tornado in the United States, during the 1999 Oklahoma tornado outbreak, would be T11 using special formulas.

The formulas connect the TORRO scale number, called T, to wind speed, called v. Wind speed is measured as the fastest gust in three seconds at a height of 10 meters above the ground. The formulas work in different units like meters per second, kilometers per hour, miles per hour, and knots.

Rating process and comparisons to Fujita scale

The TORRO scale tries to measure tornado strength by looking at wind speeds. This is different from the Fujita scale, which looks at damage. But both scales often use damage to guess wind speeds, because it’s hard to measure winds during a tornado.

The TORRO scale is mostly used in the United Kingdom. The Fujita scale is used in places like North America and Europe. In 2007, the United States updated the Fujita scale to the Enhanced Fujita Scale, which improved how damage is measured. But this new scale works best for buildings in the United States and might not fit everywhere else.

The TORRO scale has more levels than the Fujita scale, which can help with weaker tornadoes. But it’s very hard to get exact measurements. Tornadoes are rated after they pass by looking at the damage they caused. Scientists use photos, videos, and damage reports to estimate wind speeds. They also sometimes use weather radar.

TORRO scale parameters

The TORRO scale has 12 levels, from T0 to T11, to describe how strong a tornado is. It helps scientists understand tornado strength by looking at the damage to buildings and other structures.

The scale uses the type of damage to decide the level of a tornado. Wind speeds and photos of damage are also helpful.