The Western Australian town of Harvey is now being evacuated as an out-of-control bushfire - which has already claimed more than 130 homes - flares up.

The blaze, which earlier wiped out the historic township of Yarloop, destroying an estimated 131 buildings and hectares of scrubland, shifted towards the town of Harvey earlier today.

"Please note fire conditions have escalated, people in Harvey are being directly evacuated," a Department of Fire and Emergency Services statement said.

A bushfire warning remains in effect for the areas east of Waroona, as well as Hamel, Cookernup, Yarloop, Harvey and surrounding areas in the Shires of Harvey and Waroona.

"A bushfire EMERGENCY WARNING remains for people in an area bounded by Old Coast Road, Forrest Highway, Bobsord Bridge, east of Waroona, Nanga Brook Road, Cunard Road, Dawn Creek Road, Pinjarra Road, south east to Harvey-Quindanning Road, Weir Road, Uduc Road and Forestry Road," the statement reads.

Many of the buildings are barely recognisable. (9NEWS)

A building reduced to rubble. (9NEWS)

The blaze is now threatening lives and homes as it moves south-easterly.

Residents have been urged to leave if they can or seek shelter.

Harvey fell into the fire's line late this afternoon after the fire broke free of containment lines and advanced rapidly. The fire is expected to approach the town of Harvey in the coming hours and residents have been urged to leave or prepare to defend their homes.

More than 200 firefighters are battling the bushfire, which is moving slowly in a south-westerly direction.

Bushfire advices have also been issued for the Perth area, with Hopeland and the south-eastern part of Forrestdale in the city of Armadale affected.

Yesterday, one Yarloop local said there was “bugger all left” after fireballs ripped through the town of 545 residents on Thursday night, while another said the fire just couldn't be stopped.

"Once it hit the town there was no stopping it because the houses were just exploding," Ron Sackville told AAP from Yarloop, which is about 130km south of Perth.

"They were just going, one after the other, down the street here.

"The town's absolutely devastated."

As well as the homes, the hotel, the 110-year-old Yarloop Workshops and Steam Museum, the heritage doctor's residence and most of the school were all destroyed by the out-of-control blaze which has burnt out more than 58,000 hectares since being sparked by lightning on Wednesday.

A burnt-out car. (9NEWS)

Some residents stayed to defend their homes. (9NEWS)

There are reports that dozens of homes have been destroyed. (9NEWS)

A family of three, who had been unaccounted for, were found yesterday.

"We have had what I would suggest are catastrophic losses in Yarloop. This has had and will have a major impact on the community," Fire and Emergency Services Commissioner Wayne Gregson said.

Two people were airlifted out of Yarloop, while 80 were being evacuated by road.

But 16 refused to budge, including Mr Sackville, who successfully defended his home.

He told AAP he heard gas bottles and petrol drums explode as properties around him burned.

The heritage-listed Workshops had been the most intact example of a historical railway workshop in Australia.

At least 21,000 hectares have been burned. (9NEWS)

Caretaker Phil Stanton said he did not know what to do now that the workshops and his home were gone.

"It's bloody completely disappeared. It's just a cloud of ash," he told AAP.

Yarloop resident Kate Barry fled with her four children and photos, but their home was ruined.

"You couldn't breathe, it was just raining ash," she said.

Cars, fences and livestock have been confirmed lost. (9NEWS)

Another resident who stayed to protect his home, Alex Jovanovich, described the fire as crazy.

"One fireball after another. The wind, it was that frigging strong, it was unbelievable, but I managed to save my house and I saved the house next door.

"It's devastating. There is bugger all left."

Four firefighters have suffered injuries, but at least two of them were released from hospital with only minor injuries.

The fire looms over Harvey. (9NEWS)

A watch and act alert is in place for Binningup and Wellesley.

Almost 700 people have registered or sought refuge at two evacuation centres, while about 3900 properties remain without power.

DFES says food and water will be delivered to Preston Beach by air and available to residents at the general store.

The Bureau of Meteorology has forecast hot and windy conditions to continue, and lightning.

Concerns about fatigue among firefighters means interstate help may be requested later.

Premier Colin Barnett and Opposition leader Mark McGowan tweeted their support for residents.

"Thanks to firefighters and volunteers still working to contain these destructive fires," Mr Barnett wrote.

Emergency services minister Joe Francis said it was "very challenging" for the community but the government would do what it could to help.

The Insurance Council of Australia has declared the bushfires a catastrophe.