A measure of the
strength of a
tornado, based on wind speed. The scale ranges from F-0 to F-5 ("The Finger of God" according to
Bill Paxton in "
Twister"). The scale ranges are as follows:
F-0: 40 - 72 mph
F-1: 73 - 112 mph
F-2: 113 - 157 mph
F-3: 158 - 205 mph
F-4: 207 - 260 mph
F-5: 261 - 318 mph