Authorities warned it could be days before the blaze that started in strong winds and high temperatures on Wednesday was contained after it ripped through tinder-dry semi-rural properties and a nearby suburb.
But a slight reprieve in the weather on Friday has helped firefighters contain 95 per cent of the fire, Chief Superintendent Metropolitan David Gill says.
Crews have been stretched by the vast extent of the blaze which has burned through 1800 hectares. (Aaron Bunch/AAP PHOTOS)
"Another long night for firefighters and crews," he told ABC Radio.
"And we can't forget the impact that's having on the community."
Mr Gill warned it would take considerable effort to get the blaze fully under control.
Firefighters are concerned about a forecast southwesterly change in wind direction that could potentially threaten the previously untested northern flank of the fire.
Crews have been stretched by the vast extent of the blaze - which stretched 53km in perimeter and had burned through 1800 hectares of bush - in their efforts to patrol containment lines and put out spot fires.
A return of hot and stormy conditions across the weekend could result in dry lightning that risks igniting further fires.
Residents in the path of the bushfires in WA are monitoring the threat and preparing to leave. (Aaron Bunch/AAP PHOTOS)
It was too late on Thursday for many people to leave in eight suburbs in the City of Wanneroo and the City of Swan, in Perth's northeast.
However, as of 1.30pm local time on Friday, emergency warnings only remained in place for parts of Jandabup, Melaleuca, Wanneroo and Mariginiup thanks to lighter winds and high humidity.
More than 100 firefighters worked through Wednesday night to save homes when the massive blaze sparked in Gnangara Pine Plantation, forcing hundreds of families to leave as embers rained down.Â
Teams worked on Thursday to assess damage to properties so evacuated residents could be informed, with fears more destroyed homes would be found.
More than 1000 people were also left without power as critical infrastructure was brought down in unforgiving temperatures that peaked at 37C on Wednesday and 39C on Thursday.
East Wanneroo Primary School and Wanneroo Secondary College remain closed.
Banksia Grove residents were forced to evacuate as a bushfire drew closer to their homes. (HANDOUT/RACHAEL HAYWARD)
Emergency Services Minister Stephen Dawson said a huge amount of firefighting resources, including multiple water bombers, were being used to battle the blaze.
"This is a significant fire ... this will be a long-running incident and could take some time before the fire is brought under control given the situation we find ourselves in terms of the wind and high temperatures," he said.
A number of firefighters have suffered smoke inhalation and minor injuries and one crew was involved in a "burnover" incident while in a truck.
After peaking at 39C on Thursday, the forecast is for 33C on Friday and 39C on Saturday and Sunday.
27°C