F-1: 73-112 mph, mobile homes pushed off foundation or overturned

F-2: 113-157 mph, considerable damage, mobile homes demolished, trees uprooted

F-3: 158-205 mph, roofs and walls torn down, trains overturned, cars thrown

F-4: 207-260 mph, well-constructed walls leveled

F-5: 261-318 mph, homes lifted off foundation and carried considerable distances, autos thrown as far as 100 meters

SOURCE: FEMA