A suspected tornado packing winds in excess of 110km/h smashed into Perth's northern suburbs on Monday morning, the Bureau of Meteorology has confirmed.
The tornado moved through the northern suburbs of Perth for about 10 minutes, between 11.10-11.20am.
Building and tree damage was reported in Sorrento, Duncraig, Warwick, Hamersley and Balga.
"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 bureau said.
"The suspected tornado was a result of a cold front passing through the Perth metro area between about 11am and 1pm WST."
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.
In Perth they have been known to occur 2 to 3 times per winter.
Gusty showers and thunderstorms with small hail were predicted to continue in Perth and the South West for the duration of Monday.
The strongest wind gusts recorded in Perth was 81km/h at Ocean Reef just after 11.15am.
Rottnest Island recorded gusts of 85km/h at 10.36am.
As of 5.45pm on Monday, thousands of Perth homes remained without power.
Some of the worst affected areas were in Perth's northern suburbs.
Forrestfield was among the worst hit, with more than 2700 homes without power. As estimated restoration time of 7pm has been given.
Houses in Innaloo, Warwick and North Perth were also cut off.
More than 80 homes in East Fremantle were also hit. Power is not expected to be restored to those homes until 7pm also.
Earlier, there were reports of fallen power lines in several suburbs and at least one power pole catching fire in Greenwood.
As of 12.30pm on Monday, about 4250 homes in Perth were without power due to broken power lines.
Power lines and a tree have fallen down in Balga on Newbury Street.
Main Roads warned of 'surface flooding' in several areas. The Mitchell Freeway southbound near the Reid Highway exit was affected, but has since cleared.
A pot hole was also causing concerns on Guildford Road eastbound, after Fisher Street in Bassendean but was soon fixed.
Traffic lights were out in several areas including South Street and Kwinana Freeway east in Bull Creek but were soon restored.