NSW fires: state faces 'lethal' conditions as temperatures forecast to soar past 40C

RFS commissioner says despite lower wind speed on Tuesday, high temperature and low humidity will make it a ‘difficult day’ with the New South Wales bushfires

NSW is facing a potentially “lethal” cocktail of bushfire conditions with smoke pollution set to smother Sydney and temperatures to soar past 40C.

The Rural Fire Service commissioner, Shane Fitzsimmons, says wind speeds won’t be as high as previous dangerous days, but this will be cancelled out by high temperatures and low humidity.

“It’s not as bad as the catastrophic weather we had weeks ago, but it’s certainly going to be another difficult day, particularly given the scale and complexity of these fires and their proximity to so much more built up and populated areas,” he told reporters on Monday.

“We’ve got fires effectively stretching now from the Queensland border right down to our far south coast area.”

Fitzsimmons said his firefighting crews were beginning to feel the pinch amid an unprecedented NSW bushfire season in which six lives and more than 680 homes have been lost.

“They’ve been flogged now for months, particularly up in the north ... and [with] the fire activity extending further south, we’re literally rotating through thousands of people every day, every week,” he said.

Crews are working on a so-called mega-fire north-west of Sydney, which was formed when the huge Gospers Mountain blaze merged with the neighbouring Little L Complex, Paddock Run, Three Mile and Kerry Ridge fires.

The RFS says the mega-fire will continue to burn until it is doused with rain.

“[Tuesday] is a very dangerous day for NSW given the combination of very hot, windy conditions and that has been lethal in the last few months,” the premier, Gladys Berejiklian, said.

“We know, given the horror summer we’re likely to have with hot, dry, drought conditions, everybody doing their bit is important.”

The NSW Health environmental health director, Dr Richard Broome, said Tuesday is likely to be “very hot and very smoky”.

“It’s going to be putting a lot of stress on vulnerable people, particularly elderly people who have existing heat and lung conditions.”

The NSW environment department says air quality will be poor in Sydney on Tuesday and could “cause symptoms, especially with people with heart or lung disease”.

Weather bureau state manager Jane Golding says temperatures could be higher than 40C in greater Sydney, the Hunter, the Illawarra and northern parts of the state.

There were almost 90 fires burning across NSW on Monday evening with 39 of those out of control.

The RFS is forecasting a “severe” fire danger for Greater Sydney, Illawarra-Shoalhaven, the Greater Hunter, the ACT and the southern and central ranges on Tuesday.

Total fire bans are in place for each of these regions, as well as the Monaro, the southern slopes, the eastern Riverina, and the north-western parts of the state.

The NSW Police deputy commissioner, Gary Worboys, reminded the public not to leave children or pets unattended in vehicles.

“Not only is it dangerous, it can be deadly,” he said.