| Fujita Scale |
Article Index for Fujita |
Shopping Fujita |
Website Links For Fujita |
Information AboutFujita Scale |
|
Educated guesses at Wind Speed ranges were made based on the damage seen, but the original numbers have since been found to be higher than the actual wind speeds required to incur the damage described at each category. The error manifests itself to an increasing degree as the category increases, especially in the range of F3 through F5. The wind speeds listed should not be taken literally—the National Oceanic And Atmospheric Administration notes that “…precise wind speed numbers are actually guesses and have never been scientifically verified. Different wind speeds may cause similar-looking damage from place to place—even from building to building. Without a thorough engineering analysis of tornado damage in any event, the actual wind speeds needed to cause that damage are unknown.”http://www.spc.noaa.gov/faq/tornado/f-scale.html Beginning on February 1 , 2007 , the Fujita scale will be updated to the Enhanced F Scale (EF Scale) for operational use in the United States. The Enhanced F Scale accounts for different degrees of damage that occur with different types of structures, as well as damage to things other than structures. The scale was introduced in 1971 by Tetsuya "Ted" Fujita of the University Of Chicago who developed the scale together with Allen Pearson (path length and width additions in 1973 ), head of the National Severe Storms Forecast Center (predecessor to the Storm Prediction Center ) in Kansas City, Missouri . CURRENT FUJITA SCALE Derivation The gap between F0 and F1 corresponds to the eleventh and twelfth levels of the Beaufort Scale , "violent storm" and "hurricane" respectively. Theoretically, the wind speeds for F11 and F12 correspond to Mach Number 0.9 and 1.0 respectively. This provides a smooth relationship between the three scales. From these wind speed numbers, Qualitative descriptions of damage were made for each category of the Fujita scale, and then these descriptions are used to classify tornadoes.http://www.spc.noaa.gov/efscale/ The diagram on the left illustrates the relationship between the Beaufort, Fujita, and Mach number scales. Parameters The six categories are, in order of increasing intensity (F6 is not in use):
SEE ALSO
REFERENCES EXTERNAL LINKS
|
|
|