From Wikipedia, the free encyclopedia
A fire whirl with flames in the vortex
A fire whirl, colloquially fire
devil or fire tornado, is a rare
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 may be whirlwinds separated
from the flames, either within
the burn area or outside it, or a vortex of flame, itself.
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]
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]
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.
See also
References
External
links
Wikis
Quiz
Map
Search
