Home >> Science & Nature >> Nature

Five Categories of Tornadoes

The Fujita scale, also known as the F-scale, system is used to rate the severity of a tornado. The system was developed by Theodore Fujita in 1971 and is still used today by the National Weather Service. Tornados are rated on a scale of zero to five, with F0 being the weakest and an F5 the most severe tornado. A tornado rating is determined by the degree of damage surveyed and corresponding estimates of wind speed.

Weak Tornados
- Although, tornados with a rating of F0 and F1 are categorized as weak tornados, damage can still occur. An F0 tornado contains winds up to 72 mph and can damage chimneys and signs, as well as breaking branches and uprooting shallow trees. A tornado classified as an F1 tornado causes moderate damage with estimated wind speeds ranging from 73 mph to 112 mph. The lower range of 73 mph is equivalent to the initial winds of a hurricane. Damage may include the surface covering stripped off roof tops, displacement of mobile homes and vehicles blown off the road. Seventy-four percent of all reported tornados are considered weak.
Strong Tornados
- F2 and F3 tornados are in the category of strong storms. The winds of an F2 tornado are estimated at 113 mph to 157 mph. Winds of this speed cause significant damage. Roofs are completely torn off, mobile homes destroyed, cars are lifted off the ground and large tree limbs are snapped and broken. An F3 tornado is identified by severe damage from winds estimated at 158 to 206 mph. An F3 tornado will destroy metal buildings, tear off roofs and knock down walls of well-built houses and uproot trees flattening entire forests, as well as pick up and throw large vehicles. One quarter of documented tornados are categorized as strong. Thirty percent of tornado related deaths are caused by F2 or F3 tornados.
Violent Tornados
- Tornados rated as F4 and F5 fall into the category of violent storms. An F4 tornado contains approximate wind speeds of 207 to 260 mph that wreak devastating damage. These winds can level large sturdy houses and throw heavy steel and concrete objects. An F5 tornado is capable of leveling houses and commercial buildings, destroying outer walls and roofs and picking up cars and throwing them more than 100 meters. An F5 tornado can even strip the bark off of a tree. Wind speeds of an F5 tornado are estimated at 261 to 318 mph. Although violent tornados are very rare, they cause more than sixty-seven percent of all tornado-related deaths.
Inconceivable Tornados
- A rating of F6 has been designated for a tornado that contains wind speeds in excess of 319 mph up to 379 mph. No tornado has ever been documented with a rating of F6.

Nature