Three people are missing and 95 homes and businesses destroyed in a large bushfire south of Perth.
The town of Yarloop was devastated by the blaze, which doubled in size overnight and was being fuelled by high temperatures and gusty winds.
WA's fire authorities said there were 150 fire trucks attempting to extinguish the fire, which was apparently sparked by lightning on Wednesday.
The fires have also forced the cancellation of the Southbound music festival -- with headline performances from Disclosure, Bloc Party, Courtney Barnett and Foals -- which was set to begin today.
Yarloop, about 100km south of Perth, was in the eye of the storm. Fire and Emergency Services Commissioner Wayne Gregson told a media conference 95 homes had been destroyed, with damage also to shops, historical buildings and fire fighting services.
"However, despite our best endeavours, these conditions have meant that the fire has doubled in size and is now around 50,000 hectares," Gregson said.
Residents contacted local media to report first-hand on the damage done to their town.
Yarloop Bowling Club president Ron Sackville told Radio 6PR the town was essentially destroyed.
"There's very little of Yarloop left. I couldn't get all the way down there but understand the steam museum is gone, there are only about eight houses left, the post office survived, the pub is gone, the bowling club survived," Sackville said.
"Fortunately I have a firefighting pump and house and managed to save our house and the horses that were in the paddock -- they are in the backyard now... But I look around 360 degrees and everything is burnt to a cinder. I think the post office is the only building left standing [in the main street]. The fire was horrendous."
Overnight, firefighters were working to strengthen containment lines around the South Western highway. At first light, aerial water bombing was due to recommence.
The efforts to extinguish the blaze will be made more difficult by temperatures of more than 32C forecast for the Mandurah region on Friday along with gusty winds, ahead of a cool change early next week.
Late on Thursday, holidaymakers and residents at Preston Beach were evacuated by boat after local roads were cut.
Residents and visitors making their way to evacuation centres have told the West Australian of choking smoke and falling ash.
In issuing its emergency warning early on Friday, WA's Department of Fire and Emergency Services said the blaze was "out of control and unpredictable".
It advised people in the towns of Waroona, Hamel, Cookenyup, Yarloop, Harvey, Preston Beach and Lake Clifton they must "act immediately to survive".
The Southbound music festival was cancelled, after road access was cut off by the fire, and one local road being reserved for essential travel only. In a statement to fans, festival organisers said ticketholders would be refunded.
"Everyone on site is absolutely devastated as we were working so hard to bring the best Southbound yet. Please understand at this time we will be extremely busy dealing with the cancellation and our thoughts are with those in danger due to the nearby fire," said festival director David Chitty.
This is a breaking news story, more to come.