"Early detection" helped ACT firefighters gain control of a fast-moving bushfire which threatened homes in Canberra's east and Queanbeyan on Wednesday.
Crews will continue to work on controlling the fire on Thursday. ESA commissioner Georgeina Whelan told ABC radio that crews expected to be patrolling the fire for several days.
She said they were confident that would be able to continue to contain the fire. Ms Whelan said from Thursday 9am there would be 17 crews on the fireground.
Oaks Estate Road remains closed.
The cause of the fire is being investigated by ACT Policing and the ACT Emergency Services Agency.
It broke out in the Pialligo Redwood Forest near Canberra Airport about 4.15pm on Wednesday.
ACT ESA incident controller Matthew Mavity said an airport control tower spotted the fire shortly after it broke out and the airport's fire crew had been dispatched immediately.
The fire was upgraded to watch and act at 4.50pm with residents in Pialligo, Brindabella Park, Beard, Oaks Estate and surrounding areas warned to activate their bushfire survival plans. Nearby roads were closed, with police roadblocks in place.
It was upgraded again to emergency level at 5.20pm after it crossed the Molonglo River. Residents in Beard and Oaks Estate were warned to leave immediately.
"Properties are under threat - leave now if you are able to," the alert said.
At 5.40pm, residents were warned it was too late to leave and to seek shelter immediately.
The fire was downgraded to advice level at 7.15pm, after being brought under control.
As of 8.30pm, it had burnt out nearly 150 hectares. No homes were damaged although it came within metres of the water treatment works substation.
"We were able to contain it there," Mr Mavity said.
Mr Mavity credited "early detection and lots of units" for being able to contain the fire so rapidly.
However, he acknowledged: "It did escalate very quickly."
The fire was fueled by dry African lovegrass and fanned by north-westerly winds.
While fire conditions are expected to be challenging on Thursday, Mr Mavity said he had the resources to deal with the threat.
A total fire ban has been declared for Thursday.
Witness accounts show just how fast the fire was moving - and how quickly crews moved to combat it.
Firas Ajaj arrived at his warehouse at Beard at 4.30pm and saw the smoke. Fifteen minutes later he saw flames and was cut off from leaving.
"It spread fast," Mr Ajaj said.
"There are some strong winds."
While there was only helicopter waterbombing to begin with, there were five within less than 10 minutes, Mr Ajaj said.
Coincidentally, Mr Ajaj had offered up his warehouse to a charity collecting goods for the victims of the South Coast bushfires.
The fire came two days after the city was battered by a ferocious hail storm. The city has also, until recently, been covered in smoke haze from the blazes that have devastated the country over recent months.