Senin, 16 Maret 2015

Fire Tornado !




Fire whirl
A fire whirl, also colloquially known as a fire devil, fire tornado, firenado, or fire twister is a whirlwind induced by a fire and often made up of flame or ash. Fire whirls may occur when intense rising heat and turbulent wind conditions combine to form whirling eddies of air. These eddies can contract into a tornado-like structure that sucks in burning debris and combustible gases.

Formation
A fire whirl consists of a core—the part that is actually on fire—and an invisible core. A fire whirl can reach up to 2,000 °F (1,090 °C)—hot enough to potentially reignite ashes sucked up from the ground. Often, fire whirls are created when a wildfire or firestorm creates its own wind, which can turn into a spinning vortex of flame.
Combustible, carbon-rich gases released by burning vegetation on the ground are fuel for most fire whirls. When sucked up by a whirl of air, this unburned gas travels up the core until it reaches a region where there is enough fresh, heated oxygen to set it ablaze. This causes the tall and skinny appearance of a fire whirl's core.
Real-world fire whirls usually move fairly slowly. Fire whirls can set objects in their paths ablaze and can hurl burning debris out into their surroundings. The winds generated by a fire whirl can also be dangerous. Large fire whirls can create wind speeds of more than 100 mph (160 km/h)—strong enough to knock down trees.
Fire whirls can last for an hour or more, and they cannot be extinguished directly.

Examples
During the 2003 Canberra bushfires, a fire whirl with a diameter of nearly 500 metres (1,600 ft) with horizontal winds exceeding 250 km/h (160 mph) was documented. Further research into the fires confirmed this in 2012. 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 Hifukush
types of fire whirls
Type 1: Stable and centered over burning area.a
Type 2: Stable or transient, downwind of burning area.
Type 3: Steady or transient, centered over an open area adjacent to an asymmetric burning area with wind.

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