How is tornado damage rated?
The most widely used method worldwide, for over three decades, was the F-scale developed by Dr. T. Theodore Fujita. In the U.S., and probably elsewhere within a few years, the new Enhanced F-scale is becoming the standard for assessing tornado damage. In Britain, there is a scale similar to the original F-scale but with more divisions; for more info, go to the TORRO scale website. In both original F- and TORRO-scales, the wind speeds are based on calculations of the Beaufort wind scale and have never been scientifically verified in real tornadoes. Enhanced F-scale winds are derived from engineering guidelines but still are only judgmental estimates. Because: • Nobody knows the “true” wind speeds at ground level in most tornadoes, and • The amount of wind needed to do similar-looking damage can vary greatly, even from block to block or building to building, …damage rating is (at best) an exercise in educated guessing. Even experienced damage-survey meteorologists and wind engineers ca
