Western Australia has been battered by a "once-in-a-generation" storm, leaving a path of destruction Geraldton to Albany.

As the massive storm's set to bare down on parts of WA, the coastal town of Lancelin is tonight on high alert as huge swells threaten to breach its already eroded coastline.

Perth and large parts of the WA coastline are set to be smashed by severe rain and thunderstorms today.

The powerful weather event is being described as a "once in five-year" storm and is bringing winds of up to 125km/ph.

A rare storm event has pummelled Western Australia's south, sending trampolines and sheds flying.

The low-pressure system, which on Monday was tracking south-east, upended trees, downed power lines and turned roads into rivers.

At its peak, the storm wiped out power to 160,000 households.

Western Australia has been battered by a "once-in-a-generation" storm, leaving a path of destruction Geraldton to Albany.

Lasting damage has been done by WA's once-in-a-generation storm, turning stretches of Perth beaches into cliff edges.