A Wollongong-based bushfire expert says fire danger conditions in southern Sydney at the weekend were the worst “in living memory” for this time of year and it was “bloody lucky” no properties were destroyed.
Professor Ross Bradstock, the director of the Centre for Environmental Risk Management of Bushfires at the University of Wollongong, said the inferno that tore through a large swathe of bushland between Casula and Barden Ridge burned in “exceptional” mid-autumn weather.
Professor Bradstock has looked at decades of data from Sydney Airport and said the weather conditions on Friday and Saturday saw the fire danger index (FDI) reach 60 – the “worst level in April since the 1950s”.
“The [FDI] record for April at Sydney Airport going back 60-odd years is about 40,” he said. “That translates into severe fire danger for last weekend, as opposed to the previous maximum which is very-high fire danger.
“We’ve never seen anything like these sort of weather conditions for mid-autumn in living memory.”
An analysis of the fire – which started in the Casula area about 2.30pm on Saturday and continued to burn on Tuesday – revealed firefighters and residents saved 528 homes, three facilities and one outbuilding in fire-affected areas of Menai and Alfords Point.
Two homes were damaged and a cubby house was destroyed.
Professor Bradstock said studies of historic incidents in the Sydney area had shown the likelihood of property loss once a blaze started increased dramatically as fire danger conditions rose from very-high to severe.
“Once you get up to around the 60 [FDI] mark, like we had on Saturday, you’re getting close to 100 per cent chance of some property loss,” he said. “The fact that we didn’t lose any property is a testament to the skill and the dedication of the fires services really, they did a very good job.
Dozens of NSW Rural Fire Service volunteers and Fire and Rescue members from the Illawarra formed strike teams as part of the fire fight. Crews were gaining the upper hand on Tuesday afternoon and backburning to establish containment lines.
Hot, dry weather extends fire risk
Fire seasons lasting more than half a year are an ongoing possibility and would require more resources and better preparation.
That’s according to Ross Bradstock, from the University of Wollongong’s Centre for Environmental Risk Management of Bushfires, who said this year “has been incredible in terms of the tail-end of the season”.
“If you look at the last six months or so, we had exceptionally-dry conditions even as far back as late August and you can sort of say the fire season … is now spanning seven-plus months,” Professor Bradstock said.
The latest Bureau of Meteorology data shows there has been a severe rainfall deficiency in the Illawarra in the year to March 31. The first half of April hasn’t been much better, with just 3.2mm of rain falling at Bellambi; the monthly average is 101mm.
Daily April temperature records have fallen at Albion Park, Bellambi, Kiama and Nowra already this month.
Professor Bradstock said the potential for prolonged fire seasons was “quite concerning” in terms of cost, preparedness and the physical toll on emergency crews.