More than 10,000 homes have been without power in WA this morning, after severe weather tore down trees and powerlines across the Perth metro area and southern districts.
Easterly winds of up to 93 kilometres an hour were recorded in the Perth Hills.
Bureau of Meteorology forecaster Austen Watkins said while easterly winds were common at this time of the year, the ferocity was rare for early autumn.
"Certainly it's a lot stronger than what we normally see for this time of the year, the kind of system that we're seeing at the moment is seen every sort of two to three years," Mr Watkins said.
Western Power spokeswoman Liz Del Borrello said crews were flat out making safe downed power lines.
She said a garden shed wound up hanging from wires outside one property in the eastern suburb of Forrestfield.
"Our priority is to make the area safe and remove the debris," she said.
"From first light this morning we've had some crews that are manually inspecting the area to ensure that it is safe before we turn the power back on."
Ms Del Borrello said severe weather was continuing to hamper the work of repair crews this morning.
"It is really hazardous, so we've got to make sure crews are safe during that period," she said.
The worst affected areas include Forrestfield, Wattle Grove and Bedfordale, with nearly 4,500 outages.
The company's customer service line was inundated with more than 5,000 calls before 9:00am.
State Emergency Service volunteers spent the night responding to fallen trees and damaged roofs, and continued to receive calls for help on Sunday morning.
In Armadale a house lost its roof-mounted air conditioner, while trees fell on cars in Maddington.
"Some of the crews have already been out since 11:00pm, and finished about 2:00am, and then we've grabbed a few more who have just got out of bed again," Armadale SES volunteer Ron said.
"A report came in that the patio had gone over the roof [of an Armadale house] and the aircon was gone so we came down here.
"We've just made it safe and secure so the owner can go back in the house until the insurance company can come out."
Waroona police said debris had been blown on to the South West Highway, and urged motorists to take care.
Bunbury bushfire causes outages
Waroona had 1,500 properties without power, but the cause was a large bushfire in Bunbury's east during which a further 5,500 homes lost electricity on Saturday night.
The fire had burnt through 162 hectares of scrub and bush since it was first reported about 1:00pm on Saturday.
Some residents were evacuated from their homes as the blaze intensified yesterday, before up to 80 firefighters and water bombers brought it under control.
Crews worked through the night and into Sunday morning trying to contain the blaze.
"These gusts can be fairly unpredictable so certainly that can send embers flying ahead of the fire front … that can make fighting the fire much tougher," Mr Watkins said.
One home on Saturday suffered an estimated $40,000 damage as a result of embers.
Hills landscape super charges winds
Mr Watkins said the strong winds were also drier than usual as air was drawn in from the east by a strong high pressure system off the south-west coast.
He said the wind travelled west over the Perth Hills at high speed, causing it to interact with the landscape in a way that built intensity, bringing down trees and tearing off roofs.
"They're downslope winds with a bit of an inversion, which is essentially a lid which traps the winds in the lower levels of the atmosphere," he said.
"When they move down across the hills and foothills they strengthen."
A severe weather warning has been cancelled for Perth and the South West, but strong winds are expected to continue into Sunday afternoon.ABC