- Wind speed up to 72 mph (up to 32 meters per sec.)

- Wind speed 73 - 112 mph (33 - 50 meters per sec.)
-Roof shingles peeled back, moving automobiles pushed off roads.
Note: Sycamore Twp. photo is typical F1 damage.

- Wind speed 113 - 157 mph (51 - 70 meters per sec.)
-Roofs torn from large frame houses, large trees snapped off (this is not the same as being uprooted).
Note: Sycamore Twp. photo is light F2 damage.

- Wind speed 158 - 206 mph (72 - 94 meters per sec.)
-Roofs and some walls torn from well-constructed buildings, heavy cars lifted from ground.
Note: Sycamore Twp. photo is strong F3
(almost F4) damage.

- Wind speed 207 - 260 mph (95 - 118 meters per sec.)
-Well constructed houses leveled, structures blown a distance off foundation.
Note: Sycamore Twp. photo is strong F4 damage. In F5 damage the ground is swept clean - here most of the house is gone.

- Wind speed 261 - 318 mph (119 - 143 meters per sec.)
-Strong frame houses lifted from foundations. Ground swept clean of debris (like top of photo at left).

- Wind speed 319 - 379 mph (145 - 172 meters per sec.)
-Because of F 4/5 winds around the intense tornado vortex the F6 damage is not identifiable, so the highest tornado rating used is F5.