Enhanced Fujita scale
The Enhanced Fujita scale is a tornado category scale used to measure tornadoes in the United States and Canada, and some other countries by how bad their damage is. It is a replacement of the old Fujita scale that was made in 1971. The National Weather Service started using it on February 1, 2007 and Canada started in April 2013. More countries have used it since then. The weakest tornadoes on this scale are rated EF0, and the strongest ones are rated EF5. Tornadoes with the EF5 label represent winds faster than 200 miles an hour. No tornadoes in the United States that happened before February 1, 2007 will have their ratings changed to the new scale.