The
Fujita scale (
F-Scale), or
Fujita–Pearson scale, is a scale for rating
tornado intensity, based primarily on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determined by
meteorologists and
engineers after a ground or aerial damage survey, or both; and depending on the circumstances, ground-swirl patterns (
cycloidal marks),
radar tracking,
eyewitness testimonies, media reports and damage imagery, as well as
photogrammetry or
videogrammetry if motion picture recording is available. The F-Scale was replaced with the
Enhanced Fujita scale (EF-Scale) in the
United States in February 2007.