A fire whirl with flames in the vortex.

A fire whirl, fire devil or fire tornado is a phenomenon in which a fire, under certain conditions (depending on air temperature and currents), acquires a vertical vorticity and forms a whirl, or a tornado-like effect of a vertically oriented rotating column of air. Fire whirls are whirlwinds separated from the [[flame]. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... For other uses, see Fire (disambiguation). ... For other uses, see Temperature (disambiguation). ... Vorticity is a mathematical concept used in fluid dynamics. ... This article is about the weather phenomenon. ...

A fire whirl can make fires more dangerous. An extreme example is the 1923 Great Kantō earthquake in Japan which ignited a large city-sized firestorm and produced a gigantic fire whirl that killed 38,000 in fifteen minutes in the Hifukusho-Ato region of Tokyo.^[1] Another example is the numerous large fire whirls (some tornadic) that developed after lightning struck an oil storage facility near San Luis Obispo, California on April 7, 1926, several of which produced significant structural damage well away from the fire, killing two. Thousands of whirlwinds were produced by the four-day-long firestorm coincident with conditions that produced severe thunderstorms, in which the larger fire whirls carried debris 5 kilometers (3 mi) away.^[2] A view of the destruction in Yokohama The 1923 Great Kantō earthquake ) struck the Kantō plain on the Japanese main island of HonshÅ« at 11:58 on the morning of September 1, 1923. ... This article does not cite its references or sources. ... For other uses, see Tokyo (disambiguation). ... Not to be confused with lighting. ... San Luis Obispo, San Luis, or SLO (Spanish for ) is a city in California. ... April 7 is the 97th day of the year in the Gregorian calendar (98th in leap years). ... Year 1926 (MCMXXVI) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar. ... A thunderstorm, also called an electrical storm or lightning storm, is a form of weather characterized by the presence of lightning and its attendant thunder produced from a cumulonimbus cloud. ...

National Institute of Standards and Technology 2003 ventilation experiment that dramatically changed a fire into a fire whirl.

Most of the largest fire whirls are spawned from wildfires. They form when a warm updraft and convergence from the wildfire are present.^[3] They are usually 10-50 meters (30-200 ft) tall, a few meters (~10 ft) wide, and last only a few minutes. However, some can be more than a kilometer (0.6 mile) tall, contain winds over 160 km/h (100 mph), and persist for more than 20 minutes.^[4] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... NIST logo The National Institute of Standards and Technology (NIST, formerly known as The National Bureau of Standards) is a non-regulatory agency of the United States Department of Commerce’s Technology Administration. ... For other uses, see Wildfire (disambiguation). ... An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ... The metre, or meter (symbol: m) is the SI base unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... For other uses, see Wind (disambiguation). ...

These can also aid the 'spotting' ability of wildfires to propagate and start new fires.

See also

• Dust devil
• Landspout
• Pyrocumulus

A dust devil in the Mojave Desert. ... A landspout is a tornado not associated with the mesocyclone of a thunderstorm. ... Pyrocumulus, or fire cumulus, is a dense cumuliform cloud usually found at an altitude of 1500 m. ...

References

1. ^ Quintiere, James G. (1998). Principles of Fire Behavior. Thomson Delmar Learning. ISBN 0827377320. 
2. ^ Hissong, J. E. (April 1926). "WHIRLWINDS AT OIL-TANK FIRE, SAN LUIS OBISPO, CALIF.". Monthly Weather Review 54 (4): 161–163. 
3. ^ Umscheid, Michael E.; John P. Monteverdi, Jonathan M. Davies (2006). "Photographs and Analysis of an Unusually Large and Long-lived Firewhirl". Electronic Journal of Severe Storms Meteorology 1 (2). 
4. ^ Grazulis, Thomas P. (July 1993). Significant Tornadoes 1680–1991: A Chronology and Analysis of Events. St. Johnsbury, VT: The Tornado Project of Environmental Films. ISBN 1879362031. 

• Church, Christopher R.; John T. Snow, and Jean Dessens (July 1980). "Intense Atmospheric Vortices Associated with a 1000 MW Fire". Bulletin of the American Meteorological Society 61 (7): 682-694. 
• Fire Whirl Simulations
• Firenado on CNN

Monthly Weather Review is a publication of the American Meteorological Society. ... Thomas P. Grazulis (born 1942) is a meteorologist who has written extensively about tornadoes and is head of the Tornado Project. ... The American Meteorological Society (AMS) promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. ...

External links

• Footage of wildfire whirl
• Photo 1
• Photo 2
• Photo 3