C L I M AT E C H A N G E
FIRE-GENERATED STORMS TECHNOLOGY IMPROVES WARNING SYSTEMS BY BETHANY PATCH
The frequency of fire-generated thunderstorms has increased in the last 20 years, with Australia entering an era of violent pyro-convection. This research helps predict the formation of fire-generated thunderstorms, such as the one that formed over Lake King in Western Australia, February 2020. Photo by Christine Harper, DBCA, Western Australia
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ire-generated thunderstorms, sometimes called pyrocumulonimbus clouds or pyroCbs, are ferocious weather systems that can exacerbate the damage already caused by the bushfires that create them. While pyroCbs are only just beginning to be understood, research by Australia’s Bushfire and Natural Hazards Cooperative Research Centre is helping measure and predict firegenerated thunderstorms more effectively. This research aims to improve warning systems and assist agencies with analysis and forecasting. Kevin Tory, senior research scientist at Australia’s Bureau of Meteorology, is part of a team exploring fire-generated thunderstorm prediction. The team’s research has developed a tool that is helping fire agencies and weather forecasters predict when these dangerous storms might occur, so that fire agencies can warn communities and firefighters. Tory explains that fire-generated thunderstorms have much in common with conventional thunderstorms – both require warm, humid air to be lifted into an unstable layer above. However, far less is known about fire-generated thunderstorms, including why they have become so much more common recently.
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“We are getting better at identifying these storms with improved satellite coverage, but this can’t explain the dramatic increase in numbers of events we’ve seen globally in the last few years,” Tory said. According to Rick McRae, who has been studying firegenerated thunderstorms for almost 40 years, Australia has entered an era of violent pyro-convection since the first closely studied storm in Berringa, Victoria, in 1995. “PyroCbs are a very strong signal of how badly climate change is impacting the globe,” McRae said. “With normal fires, if you know the fuel, the weather and the terrain, then you know what the fire will be doing, with a few exceptions. A blow-up fire event displays dynamic fire behaviour –they are basically a different species of fire. They develop feedback processes.” McRae began searching for previous instances of firegenerated thunderstorms in 2003. Prior to 2001, there were two known and two suspected events in Australia. There are now 118 on the list, including 37 during last season’s Black Summer bushfires, which raged through south-eastern New South Wales and eastern Victoria; this made the Black Summer bushfires the most intense series of pyro-convective events ever recorded.
