A wild storm that lashed Perth and WA's south-west overnight caused a container ship to break its moorings and crash into the rail bridge in the port of Fremantle.
Wind gusts of 122kph hit Busselton, while 34 millimetres of rain was recorded in Donnybrook and 22 in Swanbourne.
About 20,000 homes lost power overnight, although Western Power said only 2,400 customers - mostly in Manjimup - remained without electricity this morning.
The ship that crashed into the Fremantle rail bridge was unloading a cargo of cars when its stern rope snapped, causing it to swing out into the port.
A second cargo vessel also broke its moorings and hit the refuelling vessel Parmelia 1, which was docked near the bridge.
The rail bridge has been closed to enable inspection by structural engineers.
The structural soundness of the bridge was called into question in 2011, after being hit by a refuelling barge.
David Hynes from the Public Transport Authority said commuters on the Perth to Fremantle line could expect delays.
"We're able to run trains down as far as North Fremantle, so trains will continue as normal to North Fremantle and we'll have replacement buses running between North Fremantle and Fremantle itself," he said.
"It will add time. How much we don't really know, depends on the traffic, but it's only a single stop so it's not going to be a massive amount of time, but it will lengthen the journey."
'Three years to act on warning system'
Member for Fremantle Simone McGurk said the State Government promised to install an early warning system on the rail line after a ship hit the bridge in 2011.
"They are only just now installing an early warning system to ensure trains stop automatically if the rail bridge is struck by a ship," she said.
"Three years it has taken them to act on that issue and I think that's unacceptable.
"People deserve an absolute safety guarantee that the trains will stop automatically if the bridge is struck."
Ms McGurk said the road traffic bridge adjacent to the rail bridge should also have an early warning system.
"In regard to the traffic bridge, they are not installing that sort of warning system despite successive engineering reports saying the bridge is at an unacceptably high risk of damage or collapse in the event of being struck by a vessel," she said.
"In fact, the traffic bridge needs to be replaced. Ten years ago we had an engineering report saying that bridge needed to be replaced.
"This Government is spending money on expensive repairs, but the bridge needs to be replaced."
The Public Transport Authority said the Fremantle rail bridge could be closed for up to a week.
Tornado rips through Bunbury
Meanwhile, the State Emergency Service (SES) received 32 calls for assistance, mostly from homeowners in Bunbury, after a tornado ripped through the town.
Resident Dave Hayward said the roof of his house in Twilight Street, Carey Park, was blown off in the storm.
"It was just a massive explosion and a flash of light. We heard the thunder coming from across the distance and it came across here and there was an almighty bang and then everything went to chaos. Everything was black," he said.
"In the lounge room water started pouring through the light fittings.
"We can see daylight through them now as all the roof is pretty much gone. My kids helped move my gear out last night, the house is now full of water.
"My car got smashed up in the car port, tiles have gone through the back window.
"The SES couldn't get up on the roof last night was it was too unsafe but they are going to try again this morning and tarp it over.
"In the meantime I am going to have to try and find somewhere else to move into as there is no living here."
© ABC 2014
13:48 EDT Tomorrow will be t-shirts verses overcoats as Queensland and northern New South Wales bake in temperatures in the high thirties and forties while Tasmania is dealt single-digit temperatures in bitter, snowy winds.