Courtesy of NOAA.


On 1st February 2007, the Enhanced Fujita or 'EF' Scale was officially introduced by the National Weather Service as a more accurate tornado damage rating scale within the United States.

The EF Scale officially replaced the existing 'F' or Fujita Scale that was first implemented in 1971 by Ted 'Theodore' Fujita as the first recognised tornado damage scale.

The Enhanced Fujita Scale uses the same basic parameters as the f scale with six catagories between zero and five representing the increasing degree of damage, however the new scale is seen as more accurate as it focusses on specific, descriptive damage caused by the tornado by taking into account the type of structure damaged using 28 damage indicators (or DI's). Also the EF scale determins the degree of damage (or DOD) that occured to the building based on how it was constructed. From this a wind speed is officially determined and an EF Scale rating is applied.