The United States has more tornadoes than any other country in the world. While we have a lot of experience with them, we don’t fully understand how they work and why they form. This makes them especially dangerous and hard to predict.
We do know that most tornadoes form in or around a rotating updraft of air that extends from the base of a thunderstorm. The rotation pulls up dirt, debris and other material from the ground surface, resulting in winds that can destroy buildings and other human-made structures as well as natural objects.
Tornadoes are classified by the strength of their winds and the kind and severity of damage they cause. The original scale was developed by meteorologist T. Theodore Fujita and researcher Allen Pearson. It was named the Fujita-Pearson Scale.
The Enhanced Fujita Scale (EF-Scale) was created in 2007 to standardize how tornado damage is estimated and has been used to assign tornado ratings since then. The EF-Scale expands on the original by adding more detail to how damage is rated. It uses 28 damage indicators matched to degrees of damage and allows for more precision in the rating system.
EF-1 – Light damage (