Almost every home destroyed in New South Wales during the Black Summer bushfires of 2019 and 2020 fell within the 100 metre buffer used to flag properties at highest risk, according to new peer-reviewed research.
The analysis supports the reliability of current risk mapping, but it also cautions that worsening fire weather driven by global heating may require greater separation between homes and flammable vegetation to keep properties safe.
The NSW Rural Fire Service said the findings underline the need for homes in high-risk zones to meet stronger bushfire construction standards as the state braces for what could be a challenging season.
More than 3,000 homes were destroyed nationwide in the unprecedented fires six years ago, which claimed 33 lives and killed or displaced an estimated 3 billion native animals.
Of the 2,475 homes lost in NSW, the study, published in the International Journal of Wildland Fire, found 94% were located less than 100 metres from flammable vegetation such as trees.
The 100 metre buffer is central to widely used bushfire prone land maps that guide firefighter outreach and inform planning decisions on how resilient new homes and renovations must be.
Associate professor Owen Price of the University of Wollongong, who led the research, said the results show a core element of identifying buildings at risk is essentially accurate. He said distance to vegetation remains a critical factor and the 100 metre rule performs well under many conditions.
Researchers also examined fire danger ratings on the days properties were lost. When the Forest Fire Danger Index reached extreme or catastrophic levels, homes situated beyond 100 metres also burned, Price said.
He added that this is a warning sign because the index is expected to worsen as the planet heats.
Price noted wildfire scientists are increasingly concerned about fires breaching urban areas, citing destructive recent events overseas, and said his team is studying whether similar scenarios could unfold in Australia. Proximity to other burning structures is another risk factor, he said, which is why preventing house ignitions is vital.
The study warned current regulations may become less effective over time as climate risks grow.
Melissa O’Halloran, who oversees bushfire planning at the NSW Rural Fire Service, said the research supports requiring higher construction standards for homes in designated bushfire prone areas.
She said conditions in 2019 were extreme and outside typical planning assumptions, yet the policy framework performed reasonably well, reinforcing the need for robust protection measures.
O’Halloran said post-fire investigations have found some residents did not realize they lived in bushfire prone zones. In NSW, properties in these areas can remove trees within 10 metres of a dwelling and clear understory within 50 metres.
She added the service is reviewing its main bushfire protection policy to account for increasing climate risks, noting that climate change is affecting not only temperatures but also how quickly landscapes dry and the likelihood of extreme pyroconvective fire behavior.
100 metre buffer and the season ahead
Inspector James Morris of the NSW Rural Fire Service said fire risk is already elevated this year in the state’s north, the central west and the far south coast.
He said recent high rainfall can quickly translate into fuel once vegetation dries, urging residents to prepare their properties.
He warned the state could face a tough fire season.
Scientists have warned that worsening fire weather driven by global heating may require greater separation between homes and flammable vegetation, echoing broader research into how wildfire smoke and birds respond to extreme events.
The International Journal of Wildland Fire, which published the study, is part of a growing body of work examining how climate change, land management and building standards intersect in an era of increasing bushfire risk.
More information on bushfire preparedness and current warnings is available through the Australian Bureau of Meteorology, which tracks fire weather and related climate indicators.
