The Bureau of Meteorology is warning the “deep low” system will begin impacting west-facing towns as far north as Geraldton as of Saturday evening, before moving down the coast and smashing parts of Lancelin and heading towards the state’s south west.

The Bureau of Meteorology is warning the “deep low” system will begin impacting west-facing towns as far north as Geraldton as of Saturday evening, before moving down the coast…

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

Bureau of Meteorology says WA residents should brace for wind gusts higher than 125km/h – the strength of category two cyclones

Warnings have been issued for residents throughout the state as the weather amps up on Saturday evening.

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.

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

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

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.