Tornado rips roofs from homes, recreation centre south of Perth

A tornado has flipped cars and ripped roofs from homes and a recreation centre in Western Australia's south-west.

At least 40 calls were made to emergency services after the tornado struck about 4pm on Friday in Bunbury (6pm AEST), roughly two hours south of Perth.

It's believed the tornado tore through a recreation centre with dozens of children inside in the southern suburb of Withers.

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Four St John Ambulance crews were on scene at the centre.

There were about 6000 homes without power on Friday evening with an evacuation centre opened at the Eaton Recreation Centre.

"People on Parade Road, Washington Avenue and Bussell Highway in Withers, including those in the vicinity of Hay Park Multi Sports Pavillion should be aware of fallen powerlines, trees and other hazards," Emergency WA warned.

The Bureau of Meteorology has since cancelled two severe thunderstorm warnings issued earlier in the day.

One was for people in the Greater Perth area, while a secondary warning had been in place for those in the Lower West, Great Southern and Central Wheat Belt districts.

"I just could see all this debris in the sky and I thought that's a bloody twister," a resident told 9News.

"The closer I got I could see sheds, I could see trampolines, and the noise and the wind and the rain.

"It's just unbelievable. It's what you see on the movies."

Bunbury Regional Prison was also impacted with one prisoner taken to hospital.

Multiple accommodation blocks in the minimum security section were damaged but the site has been secured.

Residents are being warned about flash flooding that may follow the storm in the area.