International Fujita scale

Parameters The 12 categories for the International Fujita scale are listed below, in order of increasing intensity. Although the wind speeds and photographic damage examples are updated, which are more or less still accurate. However, for the actual IF-scale in practice, damage indicators (the type of structure which has been damaged) are predominantly used in determining the tornado intensity. The IF-scale steps are defined by a central value and an error. The errors have been estimated to be 30% of the central value, resulting in overlapping speed ranges. The distances between the central values of the steps have been so chosen that the upper bound exceeds the central value of the next step, ensuring a balance between the resolution of the scale and the expected errors. Since ESSL required that the steps be consistent with the original Fujita scale, they introduced steps with – and + suffixes indicating steps one third higher or lower than the central value of the original scale, e.g. IF2- equals "IF2 - 1⁄3IF2" and IF2+ equals "IF2 + 1⁄3IF2". Above F2, such a subdivision was not introduced and only full steps are used. ==2023 version==

On May 6, 2023, version 0.99.9d was published, which changed it to a 9-step rating scale. In this version, the wind speed damage indicator was introduced, which made it the first tornado intensity and damage scale to use measured wind speeds and Doppler weather radar measured wind speeds. ==See also==