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

Perth and the South West are set to be pummelled by "tornado-strength" wind gusts and dangerous swells in "once in five-year" storm.

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.

Wind gusts up to 125km/h forecast to hit city as residents urged to stay away from windows

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

The entire South Australian coastline is under a severe weather warning with rain and damaging winds up to 100km/h on the way.

Residents in South Australia are being warned to expect rain and damaging wind today.

Thousands of residents in WA are without power after a major storm overnight.

South Australia is one of four states set to be smashed by severe weather this week.

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

Wild weather in Perth has left 20,000 homes without power.