What a century of bushfire data teaches us about how to save lives this summer

What a century of bushfire data teaches us about how to save lives this summer

27 December 2018

Published by https://www.abc.net.au/

AUSTRALIA – What can we learn about saving lives from studying more than a century of bushfires?

A lot — but experts warn too many Australians still do not properly understand the risks and new research suggests nine in 10 Victorians in high risk areas would not follow the prevailing advice to leave early on days of high fire danger.

Most lives have been lost on a few horror days — and in one state

Between 1901 and 2011, 825 people lost their lives in more than 260 bushfires. Of those killed, 92 were firefighters.

More than 80 per cent of the deaths were in January and February, and 61 per cent happened in Victoria.

Even more strikingly, 65 per cent of all the people killed in bushfires across that 110-year period died on just nine days, including Black Saturday in 2009 when 173 people died in Australia’s worst natural disaster.

The Victorian Bushfires Royal Commission looked at the circumstances of how 173 people died on Black Saturday.

Its analysis found that while most people were aware they were at risk, 24 per cent did not even have a basic awareness they were in danger of bushfires.

Near the bush equals high risk

The closer your home is to the bush, the more at risk you are. The CSIRO’s life and loss database analysis of 110 years of deaths in bushfires, found that:

  • 50 per cent of deaths happened within 10 metres of a forest,
  • 78 per cent happened within 30 metres of a forest, and
  • 85 per cent happened within 100 metres of a forest.

The definition of a forest is bushland covering more than 0.2 hectares — that’s about the size of four house blocks.

This finding may seem obvious but not everyone is aware of how stark that relationship is.

John Handmer, from RMIT’s school of science authored the study on Black Saturday deaths and said recent migrants to Australia might be in this category.

“Many of those people have not spent a lot of time in Australia and it’s difficult to expect those people to be really aware of the risk,” he said.

The same applies to people who are house-sitting or in holiday houses away from their usual home.

Houses on slopes are at particularly high risk during bushfires because fire travels faster uphill.

Andrew Gissing, general manager of resilience at Risk Frontiers, a private research company modelling natural hazard risks, said anyone living close to bush or grasslands was at risk.

Buildings closest to the bushland interface were most at risk and anyone living with 500 metres of the bush should be aware of the risk and how to prepare for it, though properties have been lost further than 500

More than 1 million addresses are at high risk

Risk Frontiers has estimated that nearly 1 million addresses in Australia are located less than 100 metres from bushland, putting them at the highest risk from bushfires — though not all those addresses have a house or structure on them.

Many of the locations with the largest proportion of high-risk addresses are thinly populated rural areas, but four are in heavily populated areas of our capital cities:

  • Hornsby and Ku-Ring-gai in Sydney,
  • Logan in Brisbane, and
  • The Adelaide Hills.
Top 25 Local Government Areas with a large proportion of high-risk addresses
Local Government Area State % of addresses at high risk Total population
Tasman TAS 61.7 2,372
Blue Mountains NSW 51.7 76,902
Huon Valley TAS 40.1 16,199
Eurobodalla NSW 40.1 37,229
Mundaring WA 38.1 38,159
Scenic Rim QLD 35.3 40,078
Chittering WA 30.9 5,474
Murrindindi VIC 30.0 13,730
Hornsby NSW 29.8 142,666
Ku-ring-gai NSW 29.7 118,053
Kingborough TAS 28.9 35,852
Hawkesbury NSW 28.6 64,591
Derwent Valley TAS 27.7 10,022
Toodyay WA 27.6 4,442
Murchison WA 27.3 153
Wollondilly NSW 25.3 48,520
Bega Valley NSW 25.3 33,254
Adelaide Hills SA 25.2 38,864
Ipswich QLD 25.0 193,737
Port Stephens NSW 23.5 69,556
Doomadgee QLD 23.3 1,398
Shoalhaven NSW 22.1 99,649
Logan QLD 22.0 303,384
Central Coast NSW 21.7 2,1362
Sunshine Coast QLD 20.8 294,365
Total    

1,710,011

There is no national publicly available database where you can work out if you are at risk of bushfire but the New South Wales and West Australian fire services have websites where you can enter your address to determine if it is in a fire-prone area, and South Australia has a map showing Bushfire Safer Places.

The Country Fire Authority in Victoria provides online diagrams to help people identify their property’s risk.

Taking action on high-risk days is crucial

Since at least the 1980s, public advice on what to do when a bushfire threatens has followed the ‘Stay or Go’ policy, more accurately described as ‘Prepare, stay and defend, or leave early’.

The Australasian Fire and Emergency Services Authorities Council formally adopted the ‘Stay or Go’ policy in 2005.

It was based on data showing that since the mid-1950s, the largest proportion, a quarter, of people had died evacuating late in the face of an oncoming fire, closely followed by those defending their property outside the house.

Only 14 per cent were inside a defendable property.

The many studies concluded that well-prepared houses could be successfully defended and were a safe refuge from the fire front. But Mr Gissing said Black Saturday “threw that policy on its head”.

Nearly 70 per cent of the people who died on Black Saturday were sheltering ‘passively’ in their home or a nearby structure. More than a quarter died sheltering in a bathroom or laundry.

Human geographer Katharine Haynes, senior research fellow at Macquarie University, said that sheltering should be considered a last resort or back-up in case evacuation or defence is not possible.

Her research showed that people who sheltered and survived on Black Saturday did so actively.

“You need to do it in a room in the house where visibility is good and you can see outside and there are exits,” she said.

A survey of 600 residents who survived the Black Saturday fires found that only 5 per cent had sheltered in their house.

Many Australians will be familiar with ‘fire weather’ — those hot, windy days when the atmosphere feels like the inside of a hot oven.

The Forest Fire Danger Index (FFDI) was developed in the 1960s to rate fire weather. It measures temperature, relative humidity, wind speed and via rainfall, estimates the drought factor.

Until Black Saturday, the FFDI had five categories — low/moderate, high, very high, severe and extreme.

The CSIRO analysis showed that 50 per cent of deaths in bushfires happened on days when the FFDI was over 50 — putting them in the ‘severe’ or ‘extreme’ range.

On Black Saturday, the FFDI was 155, the highest rating recorded for a major bushfire.

The data showed just what the FFDI meant for saving lives:

  • On days where the FFDI was over 100, 75 per cent of people died in buildings.
  • But at lower FFDIs people tended to die when caught outside defending property.

It led to a new FFDI category: Catastrophic, or Code Red in Victoria, when the FFDI is over 100.

The advice is clear on catastrophic fire danger days: if you live in a bushfire-prone area the safest option is to leave the night before, or early in the morning. Don’t wait and see what happens.

Leave and live

The Black Saturday Royal Commission concluded that a ‘Stay and Defend’ strategy was still a valid option in a bushfire but only under limited circumstances.

This means taking account of fire intensity, how defendable the home is, having good fire-fighting equipment and how mentally and physically fit the residents are.

“[Stay and defend] should be attempted only by people who understand and accept the risks — including the risk of death,” the Royal Commission report said.

Victoria changed its bushfire safety approach to ‘Leave and Live’ in 2014.

But the Victorian CFA’s Bushfire Community Survey released this month found that only one in 10 people in high risk areas said they would leave early on days of high fire danger.

It is the lowest proportion in the seven years that the survey has been running.

Professor Handmer said fire risk awareness was greater now than 10 years ago, but there was a gap when it came to accepting the true personal risks.

“They say, ‘I know I’m at risk’. But the next step is, ‘me and my family could be killed, and my house could burn down’. They are very confronting things to face.”

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