“It is deeply regrettable that our support operations have likely started this fire,” a statement on Tuesday from the Department of Defence said.
“Defence has taken immediate action to reduce the risk of fires being started by helicopters, including not using certain aircraft lighting in extreme weather conditions.”
The Australian Defence Force has deployed additional helicopters as it works with emergency services to ensure no people remain in the national park, which has been closed.
As of 6pm Tuesday, the Orroral Valley fire was burning at emergency level and people on Boboyan Road, Apollo Road and Top Naas Road, near the border with NSW, were being advised to immediately leave.
“Soon it will be too dangerous to drive,” the ACT Emergency Services Agency (AESA) said in a statement.
Prime Minister Scott Morrison said that ADF personnel and emergency workers had been out door knocking in the ACT.
An evacuation centre has been opened at Erindale College, 15km south of Canberra.
“Identify a safe spot to shelter in, which should be a place with more than one exit, preferably inside a brick building, away from windows and doors,” the AESA said.
“The safest spot is the place that will keep you furthest away from the intense heat from the fire. As the fire approaches and passes, the safest spot will change so be ready to move.”
Residents in suburbs on the outskirts of Canberra including Tharwa, Banks, Condor, Gordon and Calwell, as well as the remote area of the Orroral Valley, are being told to monitor the situation.
NSW RFS public liaison officer for the Snowy Monaro region Andrew Dillon said they were working closely with ACT fire services to “keep an eye on the fire” as it moved in a southeasterly direction.
The fire is expected to cross the NSW border on Tuesday night or Wednesday and could impact areas near south Michelago.
“We’ve got crews available in NSW to assist and undertake property protection if required,” he said. “At the moment, we are just planning the strategy as we head into the evening to make the most of the high humidity and cooler temperatures.”
With conditions expected to deteriorate over the weekend, Mr Dillon said crews would spend the next few days strengthening containment lines.
In addition to the Orroral Valley fire there are 56 other fires burning around NSW and the ACT, all at advice level.
On Tuesday, the RFS’ building impact assessment showed 2399 homes had been destroyed this fire season, while more than 14,300 homes have been saved.
‘The public needs to be vigilant’ amid heatwave warnings
Western Sydney should brace for a scorching weekend with temperatures reaching the lower mid-40s as severe and extreme heatwave warnings are issued across most of the state on Friday and Saturday.
“We are looking at hot conditions for the western parts of NSW and inland parts of NSW, which will gradually increase towards the coast over the coming days,” said Bureau of Meteorology forecaster Abrar Shabren.
The coastal fringes in the north and north-eastern parts of the state could experience some showers and storms, but the week ahead will mostly be dry.
There will be minimal rainfall across most fire-affected areas of the state, and while there are no total fire bans on Wednesday and no severe fire danger ratings, that is expected to change later in the week.
Tuesday was relatively mild and cloudy, but temperatures are expected to rise into the 30s towards the weekend, particularly on Friday and Saturday when the mercury could reach the mid-40s in western Sydney, including 44 degrees in Penrith.
“The public needs to be vigilant, especially the vulnerable and the elderly, who need to take care while they’re outdoors. Stay indoors in cooler temperatures, and keep yourself hydrated,” Mr Shabren said.
Matt Bungard is a journalist at The Sydney Morning Herald.
Laura is a journalist for The Sydney Morning Herald.
Anthony is foreign affairs and national security correspondent for The Sydney Morning Herald and The Age.