Scientists use gaming software to predict the fires of tomorrow

You’re standing at the window of your living room in a modest one-storey home on the outskirts of an Australian town.

Outside, the wind has picked up and the sky is darkening. A bushfire is approaching.

Researchers are using Unreal Engine to build visualisations of fire behaviour.(Supplied: UNSW/CSIRO)

If this looks like a video game, that’s because it was created using Unreal Engine, software used in the film and gaming industries to build cinematic environments.

But researchers are using it alongside Spark, a wildfire simulation platform built by CSIRO, to predict how bushfires behave under different weather conditions.

They hope the initiative will help us better prepare for Australia’s changing climate and its impact on bushfires.

Understanding the fires of tomorrow

Film industry software is helping researchers study bushfire behaviour as climate change sets new norms.

For more than a week, during what is normally the wet season, residents in Los Angeles have been battling some of the most destructive wildfires in the city’s history.

Recent wet years followed by drought have increased the amount of dry vegetation in the area. Coupled with the strong Santa Ana winds from the mountains it has set dangerous conditions for firefighters.

In fact, these sorts of unusual circumstances are becoming more common in California and around the world, as climate change exacerbates fire conditions.

Smoke and fire billow from the Palisades Fire threatening homes in the Brentwood area of Los Angeles — Smoke and fire billow from the Palisades Fire, threatening homes in the Brentwood area of Los Angeles, California. (Reuters: Shannon Stapleton)

In Australia, the trends for factors driving catastrophic bushfires — for example, high temperatures and low relative humidity — “they’re all going in the wrong [direction]”, says Professor Jason Sharples, an expert in bushfire modelling at UNSW.

Climate scientists are predicting we’ll see higher average temperatures, more frequent and intense rainfall extremes, and longer fire seasons.

In the lead-up to Christmas and Boxing Day, Victoria faced the worst bushfire conditions since Black Summer.

An out-of-control bushfire in Grampians National Park burned for weeks, razed 76,000 hectares of bushland and claimed four houses.

“We don’t expect to see bad bushfires everywhere, all the time, because of climate change,” says Sarah Perkins-Kirkpatrick, a professor of climate science at ANU.

“But when they do occur, we will be seeing more of those catastrophic conditions.”

The Australian bushfire

For this story, we’ll look at a typical bushfire under different conditions according to the Australian Fire Danger Rating System (AFDRS). The system considers forecasted weather, climatic conditions and information on vegetation type.

It classifies fire danger levels as moderate, high, extreme or catastrophic and gauges the level of difficulty to suppress bushfires under specific environmental conditions.

You might be familiar with the melon, which is colour coded to show the current fire danger rating in the area.

The 'melon' showing the Australian Fire Danger Rating System. — The ‘melon’ showing the Australian Fire Danger Rating System.(ABC News: Alex Lim)

Both the nature of bushfires and the way we respond to them are continuously evolving. In September 2022, the AFDRS was updated to incorporate improvements in fire modelling science since the original system was created in the 1960s.

Spark allows us to predict and simulate fire scenarios to study changes by adjusting temperature, wind speed and relative humidity.

Here’s an example of a fire burning in grasslands under moderate and high fire danger conditions.

Two visualisations compare fire behaviour under different conditions — Fires burning under high fire danger conditions are more difficult to suppress.(Supplied: UNSW/CSIRO)

In the latter, with higher temperatures, stronger winds and lower humidity, Spark shows an increased fire rate of spread and intensity. The high fire danger conditions mean it will be more challenging to control this blaze.

Here is an aerial view of those same fires. Under high danger conditions, the fire travelled faster and burned a greater area over the same period.

Aerial view of the previous fires burning, the latter spreads more quickly. — The view from above.(Supplied: UNSW/CSIRO)

We’ve sped up the visualisation to better show its behaviour. The fire lasted 90 minutes in full when generated by Spark.

A changing fire landscape

The Black Summer bushfires in 2019/2020 saw some of the largest burn areas in Australian history.

Victoria, including the Gippsland area where retired school principal Arick Shoemaker lives, experienced record-breaking temperatures in December 2019.

Mr Shoemaker felt he had prepared his property as well as possible. He returned early from a family Christmas in Melbourne because the conditions were so bad.

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“Nobody can prepare you for the actual event,” he tells the ABC, five years later.

“The sound, the darkness … The force of the fire is something that is hard to imagine until you have been there.”

He never expected he would stay and defend his home, but the fire came so quickly, leaving suddenly wasn’t an option.

At one point, standing in his yard in his T-shirt and thongs – he didn’t have a moment to change clothes – he thought: I am going to die here.

His main concern, he says, was how his two daughters would cope without him.

He worked until morning putting out fires. Much of the night is a blur. He put the last fire out six feet from his house. Then his fire pump died.

Five years on, he has preserved a burnt fence post, serving as a reminder of what he went through that day — a “motivating factor”.

A burned wooden fence — The fire had reached the fence to Arick Shoemaker’s house.

Arick Shoemaker at a fence at the edge of his property — Arick Shoemaker left a burnt fence post on his property as a reminder.(ABC News: Rachael Lucas )

Fires that break out in these conditions are challenging to contain. And with extreme temperatures becoming more common and the risk of heatwaves increasing, there’s more to be learned about fire behaviour.

Using Spark, we can recreate the catastrophic conditions Mr Shoemaker experienced and observe our hypothetical fire.

It is charged by ultra-dry grasslands and fanned by stronger winds. The humidity is less than 10 per cent, and the temperature is 40 degrees.

Visualisations show a fire burning under high and catastrophic conditions — Scientists expect that we’ll see catastrophic fire conditions more often in the future.(Supplied: UNSW/CSIRO)

It moves quickly towards the house, consuming dry grass.

Comparing the burn extents of each scenario shows the difference in how fires can behave.

Visualisations showing fire scenarios with larger burn extents the higher the danger rating — Many variables influence the way bushfires behave.(Supplied: UNSW/CSIRO)

But it’s important to remember that not all fires behave the same way.

Fires are a “remarkably diverse beast”, says Hamish Clarke, a senior research fellow in future fire risk at the University of Melbourne.

Climate change may impact fire danger differently in different parts of the country, for example.

But Dr Clarke says most of the projections are for increases in fire danger driven by rising temperatures and lower humidity.

“Heatwaves increasing due to climate change — that’s very clear and very easy to show,” says Professor Perkins-Kirkpatrick.

When fires create their own weather

In extreme cases, the interplay between climate factors can create fires so large they spark their own weather systems.

Scientists believe climate change could increase the frequency of this new generation of fire, including ones that can produce thunderstorms.

Fire-generated thunderstorms

Pyrocumulonimbus (pyroCb) form through a complex interplay of atmospheric conditions and large regions of intense bushfires.

An illustration shows how air is drawn upwards into the atmosphere by large fires — Fires create smoke plumes that send air upwards.(ABC News: Alex Lim)

1.Heat draws turbulent air, moisture and smoke up into the atmosphere.
2.Air cools as it rises, moisture condenses around smoke particles and forms clouds — and in unstable conditions pyroCbs.
3.Rain evaporates in dry air but generates downbursts of strong winds which can fan fires.
4.Lightning can also spark new fires great distances away from the front.

Diagram explaining the parts of a pyrocb shows a large fire generating a weather system with strong winds and dry lightning — More research needs to be done to predict a bushfire’s behaviour once it creates its own weather system.(ABC News: Alex Lim)

Dr Greg Penney was a firefighter stationed in Bunbury, WA, in January 2016. His crew was deployed to do a field changeover during the Yarloop fires, where two pyroCbs were recorded on consecutive days.

Now Assistant Commissioner at Fire and Rescue NSW, Dr Penney and his crew came face to face with an extreme bushfire.

“It was the closest I’ve come to death as a firefighter,” he recounts.

Dr Greg Penney leans on a tree frontal — Dr Greg Penney, now Assistant Commissioner at Fire and Rescue NSW, almost died in the Yarloop fires.(ABC News: Geoff Kemp)

On the way there, it felt like a regular warm summer’s day, he says.

“We went from what was very calm conditions on the highway originally to driving up towards Waroona and entering into what eventually felt like cyclonic conditions.”

The sky turned pitch black, he says, and the wind became intense. He and his crew got caught in a burnover in a pine plantation.

Fire in Yarloop — Firefighters battle the Yarloop fire in January 2016.(AFP: Department of Fire and Emergency Services)

Two firefighters with hoses standing on a road try to extinguish flames burning in the bush. — Fire crews from Bunbury Volunteer Fire Brigade fight the bushfire in Yarloop.(Supplied: Bunbury Volunteer Fire Brigade)

Dr Penney saw the side of his truck begin pyrolysis and start to off-gas — essentially, to melt and vaporise. He later learned it nearly destroyed the brake lines.

“We were fortunate in that our truck did not stop … But we were fully immersed in the pine plantations, where everything around us was fire.”

What Dr Penney experienced was likely a pyroCb.

Dozens of these events were observed during the Black Summer fires in 2019-20, far more than in any year since records began in the 1980s.

In the most extreme conditions, you may not have a simple firefront. Professor Sharples likens it to a thunderstorm — keep the wind, but replace the rain and hail with embers and flames.

A new generation of fires

In our simulations, as the weather got more extreme, Spark had less confidence in its predictions.

In other words, fires at the extreme end start to test the limits of the grasslands model that predicts the danger of a fire.

Fires are complex, and fire modelling is an evolving science where models are regularly revised and debated.

For example, Spark uses mathematical models developed over 60 years in Australia.

The silhouette of a firefighter is seen in front of a large bushfire burning high into trees. — Firefighters tackle the massive Gospers Mountain blaze in December 2019 during the Black Summer bushfires.(Supplied: Gena Dray)

The International Panel on Climate Change’s sixth report last year predicted a longer fire season in Australia and a greater number of dangerous fire weather days.

A new report in the International Journal of Wildland Fire suggests that communities will also face more multi-day fires, with limited opportunity to control the fires overnight, than had been predicted under current climate forecasts.

One of the new frontiers is figuring out how to predict a bushfire’s behaviour once it develops its own weather system.

Dr Penney’s experience as a firefighter taught him that our understanding of how fires behave, how to predict their movement, and how to prepare communities for their impact could be better.

So, he went back to uni. He now holds a PhD in fire engineering and firefighting response.

Dr Greg Penney on his desk with his hat — Dr Greg Penney went back to university to study fire engineering and fire response.(ABC News: Geoff Kemp)

As the ability of computer models to capture a fire’s behaviour improves, so does the ability to visualise them.

UNSW’s iCinema research centre, which developed these visualisations with the ABC, aims to help communities and fire agencies better appreciate the extreme nature of bushfires by recreating them in immersive 3D worlds.

The Palisades fire in LA this month grew tenfold within 20 minutes, fanned by “hurricane force” winds of up to 160km/h when it bore down on large amounts of dry bush. Thousands of homes have been lost.

Scientists say Australia, large parts of which have a similar climate to California, needs to better understand the variables that shaped these fires and contributed to this disaster.

The hope is that technology can help us better prepare and adapt for what’s to come.

Credits

Reporter/Producer: Paul Donoughue
Visualisations: Dennis Del Favero, Yang Song, Michael Ostwald, Khalid Moinuddin, Navin Brohier, Carlos Tirado Cortes, Scott Cotterell
Graphics Editor and Illustrator: Alex Lim
Editors: Tim Leslie, Fran Rimrod

Richard Hurley of the CSIRO contributed to this story. The visualisations were generated using CSIRO Spark data by the UNSW Centre for Interactive Cinema Research. The predictions were calculated using the Grasslands Fire Danger Index. For this story, we’ve translated them into the more commonly used Australian Fire Danger Rating System. The pyrocumulonimbus diagram was adapted from the BOM.

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