Tornado intensity

Tornado damage to a house in Oklahoma County, Oklahoma, hit during the Tornado outbreak of May 10–13, 2010

Tornado intensity is the measure of wind speeds and potential risk produced by a tornado. Intensity can be measured by in situ or remote sensing measurements, but since these are impractical for wide-scale use, intensity is usually inferred by proxies, such as damage. The Fujita scale, Enhanced Fujita scale, and the International Fujita scale rate tornadoes by the damage caused.[1][2] In contrast to other major storms such as hurricanes and typhoons, such classifications are only assigned retroactively. Wind speed alone is not enough to determine the intensity of a tornado.[3] An EF0 tornado may damage trees and peel some shingles off roofs, while an EF5 tornado can rip well-anchored homes off their foundations, leaving them bare— even deforming large skyscrapers. The similar TORRO scale ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler radar data, photogrammetry, and ground swirl patterns (cycloidal marks) may also be analyzed to determine the intensity and assign a rating.

Tornadoes vary in intensity regardless of shape, size, and location, though strong tornadoes are typically larger than weak tornadoes. The association with track length and duration also varies, although longer-track (and longer-lived) tornadoes tend to be stronger.[4] In the case of violent tornadoes, only a small portion of the path area is of violent intensity; most of the higher intensity is from subvortices.[5] In the United States, 80% of tornadoes are rated EF0 or EF1 (equivalent to T0 through T3). The rate of occurrence drops off quickly with increasing strength; less than 1% are rated as violent (EF4 or EF5, equivalent to T8 through T11).[6]

  1. ^ NOAA: Fujita Tornado Damage Scale
  2. ^ Tornado Damage Scales: Fujita Scale and Enhanced Fujita Scale
  3. ^ Schultz, Colin. "Here's How the Enhanced Fujita Scale Works, and This Is What It Looks Like". Smithsonian Magazine. Retrieved 2022-09-14.
  4. ^ Brooks, Harold E. (2004-04-01). "On the Relationship of Tornado Path Length and Width to Intensity". Weather and Forecasting. 19 (2): 310–319. Bibcode:2004WtFor..19..310B. doi:10.1175/1520-0434(2004)019<0310:OTROTP>2.0.CO;2.
  5. ^ Grazulis, Thomas P. (July 1993). Significant Tornadoes 1680–1991. St. Johnsbury, Vermont: The Tornado Project of Environmental Films. ISBN 978-1-879362-03-1.
  6. ^ Cite error: The named reference Basic Spotter Guide was invoked but never defined (see the help page).