Understanding firestorms

Australia experienced almost as many firestorms during the 2019–2020 Black Summer season as it did in the previous 30 years. UNSW Canberra bushfire researchers hope that discovering the answer will ensure that we don’t see a repeat of this devastating bushfire season. 

Australia’s Black Summer introduced many of us to the phenomenon of the ‘pyrocumulonimbus’, otherwise known as a firestorm.  

Firestorms are dangerous, unpredictable and so intense that they create their own thunderstorms, with strong winds and dry lightning. 

According to UNSW Bushfire, predicting extreme fires and firestorms is an integral factor in reducing the impacts these events have on society and the environment.  

Lead researcher and mathematical scientist Professor Jason Sharples examines the dynamic behaviour of bushfires, using complex equations and supercomputers to create predictive models. 

“All fires start small, but some fires grow into large conflagrations that cause most of the destruction,” Professor Sharples said. “There are significant gaps in our knowledge of the processes that cause small fires to transition into large destructive bushfires, and in our abilities to predict how these large fires behave. Our research is filling these gaps.”  

The science of bushfires integrates a range of disciplines including combustion physics and chemistry, ecology and biogeography, meteorology and climate, mathematics, statistics and computer modelling. As such, it's a complicated research area that requires extensive collaboration.  

“At the broad level, our work as part of UNSW Bushfire is to improve understanding of bushfire and associated processes, and their relation to firefighter and community safety,” Professor Sharples said.  

“This is achieved by conducting fundamental and applied research into bushfire behaviour and propagation, including coupled/dynamic effects, and developing scientifically rigorous models that integrate with fire safety and risk management systems. Our research has a particular focus on dynamic fire propagation and extreme bushfire development.” 

The 2019/20 fire season caused significant death and destruction, ongoing economic and ecological damage and social disruption. 

Professor Sharples said under climate change, the conditions conducive to these events are projected to become more frequent and failing to address this problem has strong implications for national security and prosperity.  

“The majority of the damage caused by bushfires occurs in relatively short episodes when fires escalate into extreme bushfires,” Professor Sharples said.  

“The key to keeping the community safe then comes down to being able to better identify the conditions conducive to firestorm development and understanding the processes that cause small fires to transition into large conflagrations. 

“Solving these problems informs the development of enhanced ‘bushfire triage’, which enables early detection of the fires most likely to cause problems. This permits more targeted community warnings and allows for more effective deployment of limited resources. Moreover, improved understanding of the processes that drive these large fire events provides insights into more effective mitigation strategies.”