A hazard-reduction burn that got out of control sparked one of four major bushfires that ravaged the Blue Mountains and western Sydney 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 fire 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.
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.
Wind has also made fire conditions worse, with gusts reaching 90 kilometres an hour, which was much higher than expected.
