The biggest bushfire ever seen in Western Australia’s south west has been quelled by favourable weather and water bombing, as another blaze roars to life.

An emergency warning remained in place for the forest-enveloped town of Northcliffe, about 350km from Perth, on Thursday but the risk had eased considerably.

Cooler temperatures, calmer winds and the mammoth overnight efforts of hundreds of firefighters all helped tame the fierce blaze.

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At a packed community meeting in Pemberton where some Northcliffe residents had fled, the news was met with a collective sigh of relief and applause.

While still advised to stay away, those who insist on returning home may be allowed on Friday afternoon once roads are deemed safe.

However, flame-damaged, towering karri and jarrah trees falling on cars could still be a threat.

Meanwhile, a fire that started in Lower Hotham about 180km south of Perth, in the Shire of Boddington, is now threatening nearby Quindanning.

The out of control blaze has become intense and is quickly moving east, authorities say. It is burning in forest on both sides of the Murray and Hotham rivers.

It was confirmed on Thursday one home had been lost in the area.

The toll in the Northcliffe region is two.

A light tanker seriously damaged in the WA fires. Photo: AAP

A day ago, the Northcliffe fire loomed as a major catastrophe, with emergency services minister Joe Francis declaring it “the biggest in decades” and the Department of Fire and Emergency Services labelling it “undefendeable”.

While there’s now hope disaster can be averted, the situation is still precarious, Manjimup Shire president Wade De Campo said.

He’s particularly concerned about the eastern flank as it heads towards Walpole, where 50-year-old fuel loads would make a blaze “unstoppable”.

“(But) the fire behaviour has become less erratic,” he told Fairfax radio.

“At least firies can get in there and do something with it at the moment, which is really, really heartening.”

A solid afternoon of drizzle dampened everything, helping prevent spread but hindering backburning.

Firefighters have instead turned their attention to bolstering containment lines in preparation for southerly winds and hot temperatures forecast for the weekend that could push the blaze back towards Northcliffe and even Pemberton.

Department of Parks and Wildlife spokesman Colin Ingram said the forecast for Friday looked good and hopefully strengthened containment lines would prove resilient if the wind changed.

“The weather conditions continue to favour us,” he said.

“We’ve still got a long way to go with the massive size of this fire.”

Mr De Campo said firefighters had put in an extraordinary effort to protect property considering the size and unpredictability of the blaze.

“They’ve saved a lot of homes.

“The helitacs and the bombers saved those houses.”

Fortunately for Windy Harbour, after the Northcliffe fire spread dangerously close to the seaside holiday settlement, water bombers have also saved lives and homes.

Resident Ann Rice told AAP no-one needed to be evacuated as initially feared.