What scale classifies tornadoes by the damage they cause, from EF0 to EF5?

The Enhanced Fujita scale classifies tornadoes by the damage they cause, from EF0 through EF5.

The United States adopted the Enhanced Fujita scale in 2007, replacing the original Fujita scale. It estimates wind speed from damage indicators such as homes, trees, towers, and other structures, rather than measuring the tornado’s winds directly in most cases.

The six categories run from EF0, for lighter damage, to EF5, for the most devastating damage. Each category covers an estimated three-second wind-gust range. Investigators assess the construction quality and observed damage before assigning a rating.

The scale is not a simple direct wind-speed measurement, and an apparently weakly built structure can complicate an estimate. It is also not the same as the Saffir–Simpson scale, which ranks tropical cyclones by sustained wind speed. Canada and some other countries use related or adapted tornado-rating systems.