People tend to delay preparations to defend themselves or confirm the need to leave before a bushfire until they can observe the blaze directly, research into three major fires has found.
In addition, the work by the Bushfire and Natural Hazards CRC and commissioned by the NSW Rural Fire Service found greater reliance on mobile phone warnings. With carriers offering differing coverage, however, residents were getting uneven service of those alerts.
The blazes studied included the Sir Ivan fire that began during a day of catastrophic fire danger rating last February. It burned more than 55,000 hectares and destroyed 35 houses, a church and other buildings. A coronial inquest into the event was announced this week.
The other two events examined were the Currandooley fire, 40 kilometres north-west of Canberra, and the Carwoola fire, 20 kilometres south-east of Canberra. Both burned more than 3000 hectares and began on days of severe fire danger in January and February 2017, respectively.
One finding was that people don't intend to leave their region on a day of catastrophic fire risk even though that is the official advice, said Josh Whittaker, a fire researcher at the University of Wollongong and one of the report's authors.
"If a fire starts and takes hold that day ... we are simply not going to be able to put it out," Shane Fitzsimmons, Rural Fire Service Commissioner, said. "The best we can do is to try to protect and save as much as we can, and who we can, in the path of that fire."
Most people "are going to wait until there is a fire, and make an assessment about whether they feel they are threatened before they decide to leave or stay and defend", Dr Whittaker said.
On days when conditions weren't catastrophic, people were still underestimating the risk posed by fires on "severe" or "extreme" days.
NSW has had three "catastrophic" days since the introduction of the rating after the 2009 Black Saturday fires.
As the two smaller fires showed - some 11 houses and 45 outbuildings were destroyed in the Carwoola fire alone - bushfires under severe conditions "can present significant risk to life and property", Dr Whittaker said.
About 60 per cent of the survey respondents said they found out about the fires at home. Of the others who didn't, more than two-thirds tried to return home in a bid to protect vulnerable people or animals and their property.
Some admitted to using backroads - perhaps after going to observe the fire - to circumvent roadblocks, "often putting themselves in considerable danger" such as by driving motorbikes through densely vegetated areas, he said.
Respondents said warning applications on smartphones, particularly the RFS's Fires Near Me and the website, were "easy to understand, timely and useful", particularly because they provided localised information.
Even so, SMS text messages sent to phones remained the preferred source of information. In the areas studied there were varying degrees of problems with mobile phone coverage.