Homes have been damaged, power knocked out and hail the size of golf balls has fallen as a sudden storm swept across the Perth metropolitan area.

Dozens of sets of traffic lights have been knocked out by the storm and roads north and south of the Western Australian capital have been flooded.

There are also widespread reports of property damage caused by rain, strong winds and hail.

Premier Colin Barnett says the storm may qualify as a natural disaster and has predicted the damage bill will run into the hundreds of millions of dollars.

Twenty people had to be evacuated from the emergency department at Joondalup Hospital in Perth’s northern suburbs after parts of the ceiling caved in.

A spokesman for the hospital says there is significant flooding and damage to the ceiling.

Lightning also knocked out Western Power’s north-Perth sub station, causing widespread blackouts.

Western Power says more than 150,000 properties were without power.

The utility’s call centre has received an unprecedented number of calls and Western Power is asking people not to phone unless they see a power line on the ground or have a dangerous hazard to report.

The storm’s trail of destruction extends from Joondalup down through the western suburbs and further south to Mandurah.

Flights in and out of Perth as well as metropolitan train and bus services have been disrupted.

Apartments evacuated

More than 100 people had to be evacuated from an apartment block on Mounts Bay Road near King’s Park in Perth’s CBD after the storm caused a landslide.

It is understood the emergency services are still checking to see that all residents have been accounted for.

Those evacuated from their homes are being taken to a makeshift refuge facility at the Perth Convention Centre.

Schools damaged

Several high schools in Perth’s northern suburbs will not be open on Tuesday because of extensive storm damage.

The Education Department says there is damage to about 70 per cent of classrooms at Ocean Reef High School.

Shenton College, Mindarie Senior College, Duncraig Senior High School, Tuart College and Heathridge Primary School will also be closed, as will Perth Modern School for students in years eight, nine and 10.

Significant falls

The Bureau of Meteorology’s Mount Lawley station has recorded more than 39 millimetres of rain since the storm hit, ending one of Perth’s longest recorded dry spells.

The bureau’s station at Swanbourne in Perth’s western suburbs has recorded just over 48 millimetres.

Allen Gale, from the Fire and Emergency Services Authority, says the service has so far received dozens of calls for calls for help.

He says the damage is widespread.

“A lot of traffic lights out of course and power lines across the metropolitan area,” he said.

Andrew Burton, from the Bureau of Meteorology, says it is one of the biggest storms to hit Perth in years, with wind gusts of up to 120 kilometres an hour.

“Certainly thunderstorms of this strength and the kind of conditions that we’ve got in the atmosphere, we can get gusts out of this that can be strong enough to cause some damage.”