Why doesn’t the EF Scale use the fastest one-quarter mile wind speed like the F Scale?
When Dr. Fujita developed the F Scale in 1972, the fastest-mile wind speed was commonly used as a frame of reference in both the meteorological and engineering communities. Dr. Fujita adopted the fastest one-quarter mile wind speed for the F Scale because the rapid change in wind speed in a tornado vortex would not permit the measurement of a mile of wind. Today, the frame of reference in professional practice is the 3-second gust speed. So, it is consistent to use the 3-second gust speed in the EF Scale. Will the historical tornado rating database be affected? No. The research forum wanted the tornado database to be preserved; therefore, they developed a correlation between the EF Scale and the original F Scale. The basic wind speed ranges in the EF Scale are derived from the original F Scale. The EF Scale still rates tornadoes on a scale from zero to five, with EF0 as having the lowest wind speed and EF5 as having the highest. How is the EF scale used to rate a tornado? The NWS is th
