Two men and two women have died after trying to escape bushfires near Esperance in their vehicles.
WA Police confirmed all four died in the North Cascade fire, 60km north of Esperance.
State Fire and Emergency Services Commissioner Wayne Gregson said the deceased were travelling in two separate cars, and their bodies were found in the fire area of Grass Patch, Salmon Gums and surrounding areas in Esperance overnight.
Mr Gregson said more than 300 people have been evacuated from affected areas, with 60 people fleeing to Norseman.
WA Premier Colin Barnett is expected to fly to Esperance on Wednesday to inspect the catastrophic damage.
Primary schools at Scaddan, Grass Patch and Salmon Gums have been closed.
Department of Education spokesman Ken Paris says it's believed the schools are intact.
"We believe that the infrastructure at this stage is all OK but we'll await further advice particularly with regards to Grass Patch and Salmon Gums as the day unfolds," he told the ABC.
So far, 300,000 hectares have been burned in the North Cascade fire, one of four major bushfires sparked by lightning and burning in WA's south since Sunday.
Mr Gregson said more bad weather is expected over the weekend and on Monday with severe, extreme and catastrophic fire conditions predicted across the state.
"We are working as hard as possible to get these fires under control and return the community to normal," Mr Gregson said.
He urged people in the community to heed DFES warnings.
"Do not leave it too late to put your plan into effect. If you are asked to evacuate, please do so," he said.
"It is not possible to stay and defend these types of fires."
Bureau of Meteorology acting regional director Grahame Reader said the combination of extremely hot, windy and dry conditions, plus a wind change, made the lightning-sparked fires extremely dangerous.
"When you get these troughs, it does set the scene for particularly dangerous conditions," Mr Reader said
The fire in North Cascade and is burning on both sides of the Coolgardie-Esperance Highway, between Scaddan and Salmon Gums.
The fire has burnt about 300,000 hectares and is burning out of control in a north easterly direction.
Firefighters are expecting the wind to shift from south westerly to westerly, which may push the fire east.
Salmon Gums residents are being relocated to Norseman or Esperance, while a number of roads remain closed.
A 15,000 hectare bushfire continues to threaten Stockyard Creek and Mullet Lakes. Firefighters said the fire in Merivale was contained but not controlled.
A watch and act for the Thomas River-Poison Creek area of Cape Arid National Park is in place because of a fire which has pushed through the park onto private property.
Primary schools at Scaddan, Grass Patch and Salmon Gums will be closed on Wednesday.
Homes in Scaddan, Grass Patch, Red Lake and Salmon Gums are under threat by fire now.
People in Scaddan and Grass Patch are seeking shelter at Salmon Gums Primary School.
The Merivale bushfire alert has been heightened as the fire has crossed Cape Le Grand Road and is moving towards Tyrell Road quickly.
DFES has issued a statement saying homes are not designed or constructed to withstand a fire in today's conditions and people in affected areas should leave if the path is clear to do so.
Mains water pressure may be affected and people are being warned not to rely on mains water to extinguish spot fires around their properties.
Roads remain closed on the Coolgardie Esperance Highway at the Gibson townsite heading north and at the intersection of Merivale Road and Fisheries Road heading east.
Scaddan, Salmon Gums and Grass Patch primary schools will be closed tomorrow.
DFES said approximately 15,000 hectares of land had been burnt since the fires started on Sunday as a result of lightning.
A bushfire in North Cascade is approximately three to four kilometres south of Salmon Gums, travelling in a north easterly direction.
DFES has issued an alert saying the fire is out of control and unpredictable, causing a threat to lives and homes.
Bush Fire Service and Department of Parks and Wildlife firefighters are working to build containment lines around the fires and protect Salmon Gums.
An evacuation centre is set up at Salmon Gums Recreation Centre where between 100 and 150 are seeking shelter.
CBH receival point operator Kenny Tse said a concrete grain storage facility was being used to house between 20-30 CBH workers and general members of the public.
"We were originally evacuated to Salmon Gums Primary School, but they moved us here because the walls are concrete," Mr Tse said.
"We'll be here for the next few hours I think because they just told us the fire is still a few kilometres away."
Mr Tse said not everyone at Salmon Gums Recreation Centre was moved to the CBH structure as it was their choice whether to move or not. All CBH staff had been relocated to the facility.
Homes in Scaddan are under threat by fire now.
DFES has issued an alert for people to act immediately to survive.
The bushfire is moving fast in a north-easterly direction and is expected to threaten homes in Grass Patch in the next two hours. The fire is said to be heading towards Dempster Road.
The Shire of Esperance said between 100 and 150 people from Scaddan and Grass Patch had evacuated to Salmon Gums Recreation Centre.
DFES has recommended people leave their homes if the way is clear, as staying until the last minute could be deadly.
The bushfire in the Stockyard Creek and Mullet Lakes area in Merivale is still burning out of control and is unpredictable.
DFES has issued an alert saying people need to leave or get ready to actively defend their homes.
People who have left their homes should not try to return until told to do so as conditions could be very dangerous.
Firefighters at the scene have predicted a wind change could impact agricultural land in Merivale into the night.
Experienced firefighters were said to be fatigued as thousands of hectares had been burnt since Sunday.
The Esperance Shire are asking for donations of food and water to be delivered to the DFES office at shop 1a Esperance Business Centre next to Subway.
DFES has issued a warning for people in Scaddan to act immediately to survive.
Homes in Scaddan, Grass Patch, Red Lake and Salmon Gums will be under threat by bushfires in four hours due to a change in wind expected at 7pm.
Burning embers are causing spot fires up to 100 metres ahead of the fire front and are likely to hit homes in the area.
The Esperance Shire are assisting people evacuate from Scaddan after a bushfire jumped the Coolgardie-Esperance highway restricting people from heading south.
At least three backpackers were seeking shelter at the Esperance Civic Centre, which has been set up as an evacuation centre.
Salmon Gums Primary School was also acting as an evacuation centre and Cascade Recreation Hall was on standby to offer shelter to those in need.
DFES has sent eight managers and four volunteer trucks from Perth to help contain three "out of control" bushfires in the Esperance Shire.
The bushfire in North Cascade is said to be moving fast in a south easterly direction.
Winds are expected to change at approximately 7pm to a south westerly direction meaning Scaddan, Grass Patch, Red Lake and Salmon Gums could be threatened by fire.
Firefighters have described the fires in North Cascade and Merivale as "out of control and unpredictable".
Approximately 60 Bush Fire Services and Department of Parks and Wildlife (DPaW) firefighters are working to build containment lines around the fires under difficult weather conditions.
Ground crews are being supported by aerial assistance and are expecting further support from DFES in the coming hours.
The Esperance Shire has set up the Civic Centre as an evacuation point.
A fire burning in Griffiths Nature Reserve is heading towards Bishop Road in North Cascade.
Conditions have worsened increasing the threat to homes and lives in the area.
DFES has issued a warning for people to leave or actively defend their homes, as spot fires are starting fires up to 100 metres ahead of the bushfire front.
2pm: Fires continue to burn in the Shire of Esperance with three areas burning out of control in North Cascade, Merivale and the Mount Ragged area of Cape Arid National Park.
The Bureau of Meteorology have issued a "Catastrophic Fire Danger" warning for the Esperance Shire Inland, with strong northwesterly winds predicted to reach 100 kilometres per hour until 6pm tonight.
Advice has been issued by the Department of Fire and Emergency Services (DFES) for people in the Stockyard Creek and Mullet Lake areas in Merivale to leave or actively defend their homes.
DFES have issued a WATCH AND ACT alert for people living in the residential estate at the end of Stockyard Creek Road saying homes and lives could be at risk.
Israelite Bay (Fisheries Track), Gora Track, Pt Malcolm Track and Balladonia Track (Mt Ragged) remain closed.
The following Intersections are closed in the Cascade area: Cascade and Rollonds Road, Cascade and Edwards Road, Cascade and Neds Corner Road, Cascade and Fields Road, Neds Corner Road and Grass Patch Road, Grass Patch and Fields Road, Grass Patch and Belgian Road.
The following intersections are closed in the Merivale area: Merivale Road and Fisheries Road, Merivale Road and Tyrrells Road, Merivale Road and Cape le Grand Road.
Access to Cape Le Grand remains closed.
The Esperance Shire released a statement saying both the Merivale and North Cascade bushfires had broken their containment lines and weather conditions were making fighting the fires difficult.
Cascade and Merivale fires were said to be posing a risk to both private and public property.
The public have been requested to avoid affected areas to allow fire fighters to concentrate their efforts on the fires.
Three fires are burning in the Mount Ragged area, east of the Balladonia Track, in the northern part of Cape Arid National Park.
Esperance Volunteer Fire and Rescue Service captain Lonica Collins said weather conditions were not looking favourable with a frontal passage movement with strong winds and high temperatures hitting the affected areas.
"Fire fighting crews are working to try to contain the fires and are urging the community to prepare their properties ... and revise their bushfire plans as the fires are still out of control," Ms Collins said.
Dale Johnson and her family have lived at their Naranda Springs property on Merivale Road for the last 10 years, having spent 40 years on a property at Gibson before that.
In that time Mrs Johnson said they'd seen their fair share of fires and were impressed by the improved efficiency of volunteer fire services in Esperance.
Mrs Johnson said they had two fire brigades on their property around midday today fighting fires that destroyed several paddocks in front of their house.
Mrs Johnson made the decision to enact her family's fire safety plan and evacuate her home at 3pm on Tuesday, while her husband, two sons and son-in-law helped fire fighters contain the blaze.
A wind change was predicted to take the fire up to the Johnson's house later in the afternoon.
Flames could be seen "leaping into the air" 5km from the Johnson's property and embers were starting spot fires in surrounding paddocks.
Mrs Johnson said at the end of the day, all that mattered was getting yourselves out safely if there should be a violent change in the fire's conditions.
The Esperance Shire could not confirm which volunteer bush fire brigades were fighting the fires, but Ms Collins said she was preparing food for roughly 60 volunteers on Monday night.
Beaches between Wylie Bay and Cape Le Grande remain closed as a result of the fires and unpredictable weather conditions.
As a neighbourhood the Merivale Road farmers were said to be looking out for each other and helping volunteer fire fighters where possible.
"We're as prepared as you can be and that's all you can do really," Mrs Johnson said.