In the 1970s, University of Chicago weather scientist Ted Fujita decided that a better way to measure tornadoes would be based on how much damage they do.
His system, the Enhanced Fujita Scale, or EF scale, is widely used to measure tornadoes today.
Here’s the ranking:
EF-0: Wind speeds of 104 km/h to 136 km/h. Light damage: Broken tree branches, some damage to gutters or siding, light-rooted trees pulled up
EF-1: 137 km/h to 177 km/h. Shingles stripped off roofs, mobile homes turned over, broken windows
EF-2: 178 km/h to 217 km/h. Winds can pull the roof off a well-constructed house, snap or uproot large trees and lift cars off the ground.
EF-3: 218 km/h to 265 km/h. Entire homes can be destroyed, large buildings like shopping malls can be severely damaged, trains get flipped, heavy cars picked up and thrown and buildings with weak foundations can be carried off.
EF-4: 266 km/h to 321 km/h. Well-constructed and framed houses flattened.
EF-5: Anything over 321 km/h. As the Weather Channel puts it: “Incredible phenomena will occur.”