Trees are down and building damage has been reported after a suspected tornado ripped through Perth's northern suburbs, as an intense cold front hits Western Australia's south.

The State Emergency Services has received 44 calls for help, 42 of which were in the metro area.

The Bureau of Meteorology (BOM) said the suspected tornado moved through parts of Sorrento, Duncraig, Warwick, Hamersley and Balga at speeds of more than 110 kilometres per hour.

A fallen tree across bottom of Katrine Way, Hamersley. It's blocking the entire road. ( Facebook: Perth Revenue Raisers )

"This damage is consistent with winds estimated to be in excess of 110 kilometres per hour, and the path is also consistent with that of a typical cool season tornado," the BOM said in a statement.

A severe weather warning was issued due to isolated areas of dangerous wind gusts, but has since been cancelled.

A fallen tree has also caused damage to a house in Margaret River.

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The BOM said wind gusts of 82 kilometres per hour had been observed in Mandurah just after 10:00am as the strong front crossed the coast.

Cape Leeuwin recorded a gust of 96 kilometres per hour at 7:00am, while Rottnest recorded winds of 89 kilometres per hour about the same time.

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Tornadoes typically occur two or three times in Perth during winter, the BOM said.

"Typical tornado paths are around 50-150 metres wide and several kilometres long, and damage to houses in the path can range from minor roof damage to complete demolition," it said.

"They often last as little as half an hour, but by that time the damage is done."

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The Department of Fire and Emergency Services is advising people to be careful of fallen trees and powerlines, as well as stormwater drains and streams.

It said people should assess their home, car and property for damage and contact their insurer if damage has occurred.

Gusty showers, hail and thunderstorms are expected to continue in Perth and throughout the South West for the rest of Monday.

Roads across Perth, including here in White Gum Valley, have flooded. ( ABC News: Barry Dux )