Strong winds over Perth and the South West of the state overnight have uprooted trees and brought down powerlines, leaving 20,000 people without power.
Western Power says the blackouts are affecting customers mostly in the towns of Manjimup, Bridgetown, Busselton, Augusta and Bunbury.
It says crews are being redeployed to the worst affected areas.
Western Power's CEO Paul Italiano says 16 crews in the South West are trying to restore power as soon as possible.
He says a fault could be responsible for the high number of blackouts in certain areas.
"The concentration [of blackouts] in Manjimup, Bridgetown, is because we've got a transmission line that has tripped," he said.
"Transmission lines cover a long distance so we are trying to get a helicopter in the air to run the line and find out where the fault is.
"The conditions haven't been conducive to getting a chopper up at the moment, so we have crews running the line from the ground, but pretty soon we'll have a helicopter in the air and we'll be able to find out where it is pretty quickly."
There were 400 homes that were blacked out in Perth.
The winds have also caused roof and water damage to homes in Rockingham, Stirling and Inglewood.
The State Emergency Service received close to 170 calls for help since the bad weather started.
A wind gust of 146 kilometres an hour was recorded at Cape Leeuwin just before 11:00 pm last night.
Collie East has recorded 44 millimetres of rain but falls have been lighter in the city with Perth recording five millimetres and Bickley 20.
The Department of Fire and Emergency Services has issued an alert over continuing bad weather from Northam to Israelite Bay.
It says this includes communities near York, Southern Cross, Narrogin, Katanning, Albany and Esperance.
And, a flood warning has been issued for Donnybrook.
The State Emergency Service says minor flooding of the Preston River is expected today, with water levels expected to rise quickly.
The SES is warning people to stay away from storm drains and pipes and not to drive where water depth is not known.
And, residents in Perth and the south-west are being warned to prepare for another severe cold front later today.
The Bureau of Meteorology says the front will hit early this evening and last most of the night.
The Perth metropolitan area has recorded its wettest September for more than 90 years.
So far this month Perth has recorded 129 millimetres of rain - making it the wettest September since 1923.
The average for the month is 81.
© ABC 2013
14:43 EDT Tropical Cyclone Kate has only caused minor damage on Cocos Islands after passing to the north of the tiny community, more than 2,000 kilometres off the Western Australian coast.