WA town on high alert for huge swells as monster storm hits state

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A once-in-five-year storm is due to hit Perth in coming hours, with heavy rain already drenching parts of Western Australia.

The massive storm has put the coastal town of Lancelin on high alert tonight, as huge swells threaten to breach its already eroded coastline.

The Lancelin Sands Hotel owner Glenn Trebilcock took matters into his own hands today, loading 25 tonnes of sand into bags.

WA radar at 9.30pm Sat May 30

"We'll basically crane them over the side and drop them down, put them in place," Trebilcock told 9News.

His hotel sits just metres from the ocean, along a stretch of coastline already scarred by erosion.

"We lost 35 metres last year and already so far this year we've come close to about 10 metres that we've lost," he added.

It's not just Lancelin on edge – coastal communities from Kalbarri to Esperance are bracing for huge swells and potential flooding as the storm bears down on WA.

Glenn Trebilcock sandbagging

The impacted area may expand over the weekend as it's an "evolving weather situation", according to the Bureau of Meteorology (BoM).

According to Weatherzone, the severe weather is being caused by a rapidly deepening low pressure system known as a "bombing low".

"For southwest WA, this means a rapidly worsening spell of weather through the weekend, with damaging to destructive winds, heavy rain, thunderstorms, large surf and hazardous marine conditions likely before the low shifts away early next week," they said.

Wind gusts of up to 125km/h are forecast for tomorrow, also bringing a risk of tornadoes.

An "unusually strong" winter system is set to lash parts of Western Australia.

Severe thunderstorms are also predicted with up to 60 millimetres of rainfall, which could cause flash flooding, and waves that could reach more than 8 metres.

Across the state, operators are taking no chances over the forecasted conditions, with Rottnest ferry services cancelled for tomorrow.

Several campgrounds have been closed but others are open and some campers are choosing to stay at their own risk.

Meteorologist Ilana Cherny said there will likely be a second burst of "very strong winds" with a risk of locally destructive gusts across Sunday evening into Monday morning for communities from Lancelin to Albany.

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WA storm

Severe thunderstorms could also develop through the central west and extending through to the lower west.

"In addition to those winds and rain which we could see with the thunderstorms, we may also see some very localised tornadoes, which if they develop would be very fast-moving and short-lived."

The message from authorities is to secure loose items, stay away from dangerous surf and check in on vulnerable neighbours as the system moves through.