Fujita (foo JEE tuh), Tetsuya (tet SOO yuh) Theodore (1920 - 1998) was a Japanese-born American meteorologist. He developed the Fujita scale, or F-scale, which allows scientists to estimate the wind speed of tornadoes by the damage they do on the ground. He was also the first scientist to identify microbursts, sudden, severe downdrafts that can result in winds of 150 miles (240 kilometers) per hour on or near the ground. Often known as “Mr. Tornado,” his decades of study of tornadoes and related phenomena contributed greatly to our knowledge of severe storms and tornadoes.

Tetsuya “Theodore” Fujita was born in Kitakyushu City, Japan, on Oct. 23, 1920. In 1943, he earned a bachelor's degree in mechanical engineering from the Meiji College of Technology. Fujita then taught at his alma mater and at Kyushu Institute of Technology. He earned a Doctor of Science in meteorology from the University of Tokyo in 1953. That same year he began working as a visiting research associate at the University of Chicago. He would continue his affiliation with the university until his retirement in 1990, teaching and conducting research.

In 1971, Fujita developed the Fujita scale, a gauge of tornado wind speed and damage. This scale, with ratings from F-0 to F-5, allowed scientists, for the first time, to estimate wind speed of tornadoes. Previously, all tornadoes had been classified together because scientists had no way of measuring their strength.

Fujita also studied the phenomena of microbursts, or downbursts. During an aerial survey of damage from a tornado, he noticed the patterns of damage that were similar to those he had seen weeks after the atomic bombing in Hiroshima and Nagasaki in 1945. He determined that severe storms can cause microbursts. His work led to the use of Doppler radar at airports, dramatically improving air safety.

Fujita helped train a new group of meteorologists to continue his groundbreaking work.