The Fujita Scale (F-Scale), or Fujita-Pearson scale was developed by meteorologists and wind engineers to rate the intensity of a tornado by examining the damage caused by the tornado after it passes. The scale was updated in 2007 and is now called The Enhanced Fujita Scale.
After the storm passes, a ground and/or aerial survey will identify ground-swirl patterns (cycloidal marks). This, along with visual damage, radar tracking, video, photographs, and eye-witness accounts are all factored in together to then determine the F-Scale of the tornado.
