Millions of people have been urged to batten down ahead of a rare monster storm expected to smash coastal communities across a vast area.
Destructive winds, massive waves and torrential rain are forecast for Western Australia's southwest across the weekend, the Bureau of Meteorology says.
"This winter system is unusually strong," meteorologist James Ashley told reporters on Friday.
"It's the type of system we don't see very often ... (and) it's likely to be the strongest winter system we see this year, and may be the sort of system we only see every four or five years."
The storm is expected to impact communities from Geraldton to Albany, along 1200km of coastline.
Destructive winds gusts of 125km/h or more, 50mm of rainfall, flooding in low-lying areas and beach erosion are possible.
