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Learning from 100 years of bushfire loss data

By Bianca Nogrady

December 20, 2016

burned out house
Property destroyed by fire at Kinglake after the ‘Black Saturday’ bushfires.

More than 60 per cent of people who perished outdoors in Australian bushfires over the last century did so within sight of their own homes.

This is one of many sobering insights from CSIRO’s analysis of data on property and human lives lost to bushfire, between 1901 and 2011.

Until recently, much of what was known about the circumstances surrounding the people who lost their lives and the homes that were razed was based on the stories of survivors and of witnesses, and on anecdote.

But now, examining the wealth of data that is available, researchers have revealed some surprising – and often disturbing – patterns in how, when and where lives and homes have been lost to bushfire. During this period, a total of 733 civilians and 92 firefighters lost their lives in bushfires, and just over 11,000 homes were destroyed.

Getting caught out close to home

The analysis found that, during this period, 733 civilians and 92 firefighters died in bushfires, and just over 11,000 homes were destroyed.

But one figure in particular stood out. A graph of the number and location of deaths that occurred outside the home showed that around 60% of these people died within 100 metres of their home.

What does this discovery reveal about human behaviour?

“There are lots of accounts of people talking about their intentions to wait and see and to stay with their house, but then when the effects of fire start building up around them they have a sudden change of heart and decide to flee,” says CSIRO research leader Justin Leonard.

“Of course there are the education programs which are trying to say don’t wait and see, don’t freak out at the last minute, but human nature is still taking people down that path.”

graph showing bushfire deaths in relation to proximity to home
The figure shows 61 per cent of fatalities occurring within 100m of their location of residence and 80 per cent occurring within 500m. The main activity of the fatalities considered in the analyses is late evacuation (48.3 per cent). (Blanchi et al. 2012)

The finding came as a surprise to the research team, because until now they had no sense of how common that behaviour was.

Furthermore, 80% of outside deaths outside the home happened within 500 metres of home, which, as Leonard points out, wouldn’t even reach the farm gate in rural areas, or to a safer place in the neighbourhood.

Leonard spells out the implications: “What this emphasises is, if you’re not already in a safe location well before the fire has started bearing down on the area, it’s definitely too late to think about getting to one of these other places because if you’re going to die, you’re most likely going to die either in or within a few hundred metres of your home.”

Having a plan, and a backup plan

The finding reinforces the importance of making plans to get out of the area well before the weather worsens, and sticking with those plans, says Leonard.

“We have to learn to say I’m going to put down the things I hoped I was going to achieve today and just head into the city and do something different and be in a non-bushfire-prone area before 10am that day,” he says. “People really need to lock in on that idea.”

However, no plan is complete without backup plans, he adds. So it is just as important to recognise when the time has passed for you to safely make this journey.

Urban sprawl and the gender shift

The data also showed changing patterns in bushfire-related fatalities over time.

A significant gender shift that happened around the 1960s, where deaths changed from being predominantly male, to being roughly equal between men and women.

The shift reflects an earlier rural scenario, says Leonard, where it was the men who went to fight the fires or safe livestock and were caught out in the open. As urban development pushed ever further into the bush, this has changed to a scenario in which everyone is at risk, whether they are inside the home or out in the paddock.

Catastrophic conditions are the big killers

The second significant discovery supports the decision made following the devastating 2009 Black Saturday bushfires to create the new fire danger rating level of ‘Catastrophic’.

When researchers looked at the conditions on days where lives and properties were lost, 60-70 per cent of these losses happened on days that would now be classified as catastrophic.

graph showing location of fatalities from bushfire over time
A significantly greater proportion of fatalities occurred inside structures or inside vehicles in recent fires, compared to earlier fires. (Blanchi et al. 2012)

Current building regulations are only designed to be effective only up to ‘extreme’ conditions, so, as Leonard puts it: “All bets are off, even for a regulated house when you get to catastrophic.”

“In a sense, we’re resigning ourselves to the inevitability that when we have those days we’re going to lose thousands of houses and hopefully only a handful of people.”

Future-proofing our homes, now

This scenario may become even less palatable as the changing climate brings an increase in the likelihood of catastrophic weather conditions.

For many parts of Victoria, catastrophic weather conditions are roughly 1-in-20-year conditions, meaning that in any one bushfire season there is about a 5 per cent likelihood that such catastrophic bushfire conditions will arise.

By 2050, that likelihood could increases to about 15 per cent, says Leonard, and by 2100 about 30 per cent.

“The inevitability that a big fire will run on that day is nearly absolute – it just depends where in the landscape it’s going to turn up,” he says.

three people in hazard uniform walking towards property surrounded by burnt bush
Researchers at a property at Strathewen that survived the ‘Black Saturday’ bushfires.

This inevitability begs the question: Why are we not building now to anticipate the greater threat?

There is no engineering reason why houses can’t be built to deal with catastrophic bushfire conditions, Leonard says.

“The numbers of houses we expect to lose into the future will reach a point where it won’t be tolerated by society, and they will change but we should be thinking about that change now, not reacting when it reaches this point.

“It pretty much requires a paradigm shift to achieve what we’re talking about here.”

Accepting the inevitability of fire is the first step, then building and maintaining a house and surrounding landscape that is capable of withstanding fire is the logical next step.

This change in mindset would open a range of opportunities – to embrace fire as a tool and a welcome occurrence that renew the landscape around our homes – and create a landscape that will be far less of a problem when fire arrives on that next catastrophic fire weather day.


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