Fire whirl
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A fire whirl, colloquially fire devil or fire tornado, is a phenomenon—rarely captured on camera—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 vertically oriented rotating column of air. Fire whirls may be whirlwinds separated from the flames, either within the burn area or outside it, or a vortex of flame, itself.
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 away.[2]
Most of the largest fire tornados are spawned from wildfires. They form when a warm updraft and convergence from the wildfire are present.[3] They are usually 10-50 meters tall, a few meters wide, and last only a few minutes. However, some can be more than a kilometer tall, contain winds over 160 km/h, and persist for more than 20 minutes.[4]
Fire whirls can uproot trees up to 15 metres (49 ft) tall.[5] These can also aid the 'spotting' ability of wildfires to propagate and start new fires.
Visually impressive fire whirls may be encountered during dry wind gusts at the annual Burning Man festival in Nevada's Black Rock Desert, late on Saturday or Sunday evening during the burning of The Man or Temple, respectively.
[edit] See also
[edit] References
- ^ Quintiere, James G. (1998). Principles of Fire Behavior. Thomson Delmar Learning. ISBN 0-8273-7732-0.
- ^ Hissong, J. E. (April 1926). "Whirlwinds At Oil-Tank Fire, San Luis Obispo, Calif." (abstract). Monthly Weather Review 54 (4): 161–3. Bibcode 1926MWRv...54..161H. DOI:10.1175/1520-0493(1926)54<161:WAOFSL>2.0.CO;2. http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0493(1926)54%3C161%3AWAOFSL%3E2.0.CO%3B2.
- ^ Umscheid, Michael E.; J.P. Monteverdi, J.M. Davies (2006). "Photographs and Analysis of an Unusually Large and Long-lived Firewhirl". Electronic Journal of Severe Storms Meteorology 1 (2). http://www.ejssm.org/ojs/index.php/ejssm/issue/view/2.
- ^ 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 1-879362-03-1.
- ^ (PDF) Otways Fire No. 22 - 1982/83 Aspects of fire behaviour. Research Report No.20. Victoria Department of Sustainability and Environment. June 1983. http://www.dse.vic.gov.au/CA256F310024B628/0/97892B7CD0C75AB3CA2572230047B454/$File/Research+Report+20.pdf. Retrieved 2009-06-26.
- Church, Christopher R.; John T. Snow, and Jean Dessens (July 1980). "Intense Atmospheric Vortices Associated with a 1000 MW Fire" (abstract). Bulletin of the American Meteorological Society 61 (7): 682–694. Bibcode 1980BAMS...61..682C. DOI:10.1175/1520-0477(1980)061<0682:IAVAWA>2.0.CO;2. http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0477%281980%29061%3C0682%3AIAVAWA%3E2.0.CO%3B2.
- Fire Whirl Simulations
[edit] External links
- Photo
- www.youtube.com Video of a Fire whirl (0:30), Brazil.
- "Rare Footage of Fire Tornado" BBC 25-Aug-2010 http://www.bbc.co.uk/news/world-latin-america-11086299
