Fighting fire with science

When predicting bushfire behaviour it's best to keep your fingers crossed. Years of experiencing fires do the unexpected has taught Australia's meteorologists and firefighters that precise forecasting is extremely challenging.

Even on seemingly safe days fires can suddenly take on "blow-up" characteristics with devastating consequences.

The fact is that bushfires are extremely complex events which can generate their own unstable weather conditions and create havoc on the ground.

Bushfire Cooperative Research Centre PhD student Mika Peace is pursuing exciting new research to better understand their behaviour to support firefighting efforts.

She is working on advanced computer simulations which give an entirely new perspective - one which is threedimensional involving interactions between the fire and atmosphere.

Already her work is providing unique insights into the way bushfires behave - information she hopes will one day provide a new weapon for firefighters and increased safety for people in bushfire prone areas.

"We're getting results which are quite unexpected and which clearly demonstrate that each fire has its own unique characteristics," Ms Peace said. "It's showing that there is no such thing as a one-size-fits-all approach when it comes to dealing with bushfires."

As a qualified meteorologist, part of Ms Peace's former role involved fire weather forecasting. Through her work she realised there were serious knowledge gaps in how we go about predicting bushfires and understanding what they are likely to do.

Australia is still using forest and grassland fire danger meters developed in the early 1960s by forester Alan McArthur. He worked out the likely chances of a fire starting, its rate of spread and intensity based on factors such as temperature, wind speed, relative humidity and the effects of drought.

"But the information is all focused on conditions on the ground and doesn't take into account what is happening in the atmosphere above," Ms Peace said. "The interactions between the fire plume and the three dimensional atmosphere can be quite dynamic.

"It's only in the past 10 years following some major fire events here and overseas that people have started to say that was great work 50 years ago, but we have much better information now and we are not really using it to the full effect."

Ms Peace's work is funded by the Bushfire Cooperative Research Centre and supported by the Bureau of Meteorology and the Department of Parks and Wildlife in Western Australia.

As part of her research she studied the 2007 Kangaroo Island bushfires and the break-out of a prescribed burn in the southwest of Western Australia in 2010. Both fires occurred during fairly benign weather conditions on what were considered to be low fire-risk days.

Four of the KI fires burned for two weeks destroying over 20 per cent of the island's vegetation while the WA fire consumed more than 10,000 hectares.

Ms Peace is using a US simulation program that couples a weather prediction and a fire behaviour model to gain a deeper understanding of how fires evolve.

"It gives us a three-dimensional view of the interaction between the fire and atmosphere, including the plume structure of the fire, how high it's going and how the winds converge," Ms Peace said.

"One of the most extreme examples of fire and atmosphere interactions was a fire tornado generated in the Canberra bushfires of 2003.

"The 2009 Black Saturday fires in Victoria are another good example. The vertical development of the fire generated thunderstorms known as pyrocumulonimbus."

Eventually Ms Peace would like to see information on three-dimensional atmospheric structure included in all fire weather forecasts.

She has presented her early findings to various land management and bushfire forums and they've been excited at the possibilities.

Being armed with such knowledge would be an invaluable tool for firefighters and be critical in saving property and lives. It would also assist in deciding the best days for fuel reduction burns, which are likely to occur more often and over bigger areas following some of the recent catastrophic bushfires.

A long-term goal is to have 3-D coupled models operating in real-time in incident control rooms, accurately predicting what fires are going to do next. But that takes considerable computing power and could be some years off yet.

To support her work Ms Peace has been provided access to eResearch SA's super computer Tizard, the state's most powerful high-performance computing system.

"Currently it takes about one day to run one simulation and four days to run one of the other simulations - so it's not quite real-time just yet," Ms Peace said. "But computing power is improving all the time and it would no doubt run faster if we had exclusive use of the system."

In the meantime Ms Peace is pleased to witness the trend of fire authorities working much closer with weather forecasters.

"In the past meteorologists have done the weather side, packaged it up and sent it off to fire managers and behaviourists," she said. "What we're seeing now is a lot more overlap as we begin to understand interactions between fire and the atmosphere."

Ms Peace hopes to further develop her interest in fireweather forecasting once she has completed her studies early next year.