The Enhanced Fujita Scale
NOAA's National Weather Service fully implements the Enhanced Fujita (EF) scale to rate tornadoes on February 1st, 2007, replacing the original Fujita Scale. The EF scale will continue to rate tornadoes on a scale from zero to five, but ranges in wind speed will be more accurate with the improved rating scale.
"The EF scale provides more detailed guidelines that will allow the National Weather Service to more accurately rate tornadoes that strike the
The Fujita scale was developed in 1971 by T. Theodore Fujita, Ph.D., to rate tornadoes and estimate associated wind speed based on the damage they cause. The EF scale refines and improves the original scale. It was developed by the Texas Tech University Wind Science and
...INCREASED ACCURACY IN DAMAGE ASSESSMENT
Limitations of the original Fujita scale may have led to inconsistent ratings, including possible overestimates of associated wind speeds. The EF scale incorporates more damage indicators and degrees of damage than the original Fujita scale, allowing more detailed analysis and better correlation between damage and wind speed. The original Fujita scale historical data base will not change. An F5 tornado rated years ago is still an F5, but the wind speed associated with the tornado may have been somewhat less than previously estimated. A correlation between the original Fujita scale and the EF scale has been developed. This makes it possible to express ratings in terms of one scale to the other, preserving the historical database.
On the web:
NOAA: http://www.noaa.gov
NOAA's National Weather Service: http://www.weather.gov
Enhanced Fujita Scale: http://www.spc.noaa.gov/efscale