What does the F stand for when they categorize a Tornado?

Question

Example: A category F3 Tornado has touched down?

Answer 1

Fujita scale, a measure of destructive power and wind speed. A F3 is twice as powerful as a F2 and so on. The Fujita scale (F-Scale), or Fujita-Pearson scale, rates a tornado's intensity by the damage it inflicts on human-built structures and sometimes on vegetation. The rating is of the most severe damage to any well-built frame home or comparable level of damage from engineering analysis of other damage. Fujita scale ratings are issued after a tornado has passed through an area, not while it is on the ground. The official Fujita scale category is determined after meteorologists (and engineers) examine damage, ground-swirl patterns, radar tracking, eyewitness testimonies, media reports and damage imagery, and sometimes photogrammetry/videogrammetry.