A hazard-reduction burn that got out of control sparked one of four major bushfires that ravaged western Sydney and the Blue Mountains this week, fire authorities have revealed.
NSW Rural Fire Service Deputy Commissioner Rob Rogers said the National Parks and Wildlife Service had been conducting a hazard-reduction burn near Hawkesbury Road in Winmalee last weekend, which flared up in Tuesday's soaring temperatures and high winds.
"Basically it was burnt on the weekend, it was patrolled on Monday, there was smouldering activity. That fire then jumped containment lines [on Tuesday]," he said.
He also revealed that arsonists are believed to have started a blaze on the same day in Marsden Park, which destroyed one home.
More than 1200 firefighters were involved in battling the four major fires on Tuesday along Hawkesbury Road in Winmalee; in Marsden Park in the Blacktown area; near Tickner Road in Castlereagh; and Richmond Road at Windsor.
Fourteen helicopters and 350 trucks from the Rural Fire Service, Fire and Rescue NSW and the National Parks and Wildlife Service were involved in the firefight.
A home was burned down at Marsden Park, in the Blacktown area. The fires also destroyed cars, sheds and other property.
Mr Rogers said investigators had determined that the Windsor fire was caused by power lines that were brought down in the high winds and ignited grass.
The cause of the Castlereagh fire is yet to be determined.
NSW Police Force Assistant Commissioner Alan Clarke said initial investigations by detectives from Strike Force Tronto indicated that arson was behind the Marsden Park fire.
"There are crime scene indicators at the source of that fire that would lead us to suspect arson activity," he said.
Mr Clarke said the the fire was believed to have been lit around Grange Avenue in Marsden Park around 12.15pm on Tuesday.
"A fire like that could easily have wiped out many, many houses. It was on the urban fringe, it really threatened a substantial community, there could have been loss of life. It’s dangerous and that’s why we will look to refer the highest charges possible," he said.
Tuesday's heat marked the second day this month of 30-plus degree weather, a record for so early in spring.
Just before 1.30pm on Tuesday, the temperature in Sydney was 31.6 degrees.
Mr Rogers said strong wind also made fire conditions worse, with gusts reaching 90 kilometres an hour, which was much higher than forecast.
He said RFS firefighters helped in the hazard-reduction operation in Winmalee, which was under the supervision of the NPWS, and he apologised to anyone who experienced property damage.
"I've got to say from the information I’ve been given, everything that could be expected to be done was done on that fire," he said.
"I don’t have any indication that anyone was negligent. It appears on first look that it’s a case of the weather was worse than was predicted, the fire jumped out, it took hold really, really quickly.
"Combined with the winds, how dry it is, the temperature and the steep terrain, fire takes hold very, very quickly."
He said the RFS also was investigating whether a hazard-reduction burn escaped and forced the closure of the M1 (formerly the F3) Motorway on Thursday.
"You would have to obviously be suspicious that it did come from a hazard-reduction, given that it was in a very close proximity to it. That’s something that we’re going to be looking at very, very closely," he said.
Any Winmalee residents who experienced property damage or loss have been urged to contact NPWS on 1300 361 967.
The story Hazard reduction burn started major Sydney bushfire first appeared on The Sydney Morning Herald.