Children playing with firecrackers during WA's heatwave are thought to have sparked a blaze which came within metres of homes in a Perth suburb last night.
The hot weather which began on Christmas Day is expected to last until next week.
Surf lifesavers are bracing for a busy few days at Perth's beaches and vets said at least two family pets had died from heatstroke.
Firefighters battled hot conditions last night as they battled the blaze which burnt 5ha of scrubland off Kenwick Road, Kenwick.
The fire began about 9.30pm and worried residents watched from their front yards as firefighters brought it under control.
As temperatures over Christmas nudged an uncomfortable 40C, vets at Murdoch Pet Emergency Centre were kept busy with seriously ill animals, including five dogs that had eaten lots of chocolate.
Centre veterinarian Melissa Claus said two elderly dogs brought in on Christmas Day later died of heat-related illnesses and another five were treated for chocolate toxicity, which can be fatal to dogs.
With the weather forecast at 40C or above for the next four days, the Health Department has urged the public to take care in the hot conditions and to check on vulnerable friends and family members.
Thousands of people sought respite at beaches and cinemas across the State yesterday as the temperature climbed to 37.5C in the city just after 12.30pm.
Crowds began dotting metropolitan beaches from early morning but strong winds forced most to leave by mid-morning.
Surf Life Saving WA duty officer James Scovell said he expected beaches to be extremely busy during the week ahead and urged beachgoers to swim between the flags and behave responsibly.
The hot weather, combined with the opening days of blockbuster movies Les Miserables and The Hobbit, ensured big crowds were drawn to air-conditioned cinemas across the metropolitan area.
Health Department chief medical officer Gary Geelhoeld said the elderly, young children and babies were more prone to heat stress than most and warned those who experience severe symptoms to seek urgent medical advice.
He said the effects of heat-related illnesses could range from mild symptoms, such as a rash or cramps to serious conditions such as heatstroke.
Despite the searing temperatures, West Australians have so far remained on track with water and electricity usage.
A Western Power spokeswoman said usage had been nowhere near the usual summer peak.
At 5pm on Christmas Day power usage hit its daily peak of 2800MW, significantly down on last summer's February peak of 4800MW.
Water usage on Christmas Day was down eight million litres on the 975 million litre daily target set by the Water Corporation.