The world's first confirmed case of a fire tornado has been documented by Canberra researchers, using evidence collected from the devastating 2003 Canberra bushfires.|
[size=1.25em]Researchers have long speculated about the ability of a fire to produce a tornado, but until now they have not been able to scientifically prove it.
[size=1.25em]The study involved collecting a vast quantity of evidence from the Canberra bushfires and has been published in the scientific journal Natural Hazards.
[size=1.25em]Lead researcher Rick McRae says the fire tornado formed in the ranges west of Canberra before pushing into the city's suburbs.
[size=1.25em]"The one that we looked at showed that as it approached the edge of Canberra, its basal diameter was nearly half a kilometre, and the damage indicates that the horizontal wind speeds around it were in excess of 250 kilometres per hour," he said.
[size=1.25em]"There is also a vertical wind in it at 150kph."
[size=1.25em]He says tornados are different to the whirls often associated with fires.
[size=1.25em]"The fire whirl is attached to the hot ground," he said.
[size=1.25em]"A fire tornado, like a true tornado, is attached to the underside of a thunderstorm."
[size=1.25em]Mr McRae says the study provides crucial information on fire behaviour.
[size=1.25em]"Our analysis indicates that the tornado had a rating of at least a two on the enhanced Fujita scale of tornado severity [scale of 0-5, with five being the worst]," he said.
[size=1.25em]"It had major effects on the behaviour of the fire on the urban edge and had enough force to remove roofs from houses and to blow cars off the road.
[size=1.25em]"It's given us an ability to recreate the behaviour of this thing and for the science community, document what a fire tornado may actually be."
[size=1.25em]Mr McRae says he hopes the case will help emergency authorities better understand the nature of bushfires.