Big storm: 'That's only half the rain'

A satellite shows the storm cell and uprooted trees are seen in Blyth, South Australia. Pictures / JMA, AAP

Flooding misery as SA Premier blames ‘catastrophic natural event’ for shutdown.

A river has burst its banks closing a major highway, downed trees and power lines are blocking roads and reports of flooding are increasing as Australia's big storm ramps up.

As Bureau of Meteorology regional director John Nairn said South Australia had only seen "half the rain", State Emergency Services warned people that flooding was affecting the mid-north town of Clare and surrounding areas.

More damage and flooding is expected, with warnings in place for five Australian states and the ACT, with the worst of the wild weather still on the way. The "catastrophic" superstorm that left the entire state without power is expected to return with a vengeance, moving east through the south coast of Australia today, according to the bureau.

SA was left in total blackout for hours early yesterday - causing travel chaos, hospital terror and reported looting of homes. Back-up generators at an Adelaide hospital failed during the outage, forcing 17 patients to be transferred to another hospital, many breathing with the help of manual respirators as they were moved.

Roofs were torn from homes overnight as gale-force winds, heavy rain and thunderstorms lashed SA and parts of Victoria.

New South Wales was last night being hit by the tail of the storm cell.

The bureau has warnings in place for damaging winds and potential flash flooding for much of the state, but has revised down warnings for heavy rains. Broken Hill has borne the brunt of the destructive winds, with gusts reaching up to 90km/h.

Thunderstorms are hitting towns in the north of the state along the Queensland border. The Riverina, central and south tablelands and parts of the Hunter, Snowy Mountains and mid-north coastal regions are all on alert.

Towns in flood-ravaged central NSW are also being told to prepare for potential flash flooding and further flooding in the next few days.

The central west community of Forbes could be inundated by a second peak of the Lachlan River at the same time the town's weekend floodwaters reach downstream Condobolin. The SES predicts the high water marks will occur sometime next week, with 30mm of rain expected yesterday and up to 20mm today.

At least 50,000 sandbags have been transported into the towns from Maitland in the Hunter Valley and extra crews have been brought in from around the state.

SA Premier Jay Weatherill insisted it was not South Australia's reliance on renewable energy that led to the blackout, as some have suggested.

"This was not a renewable energy event," he said.

The Premier said powerful wind gusts and thunderstorms smashed 22 electricity transmission stations near Port Augusta, and the toppled towers were followed by a lightning strike, which triggered a safety shutdown. "This is a catastrophic natural event which has destroyed our infrastructure. These are events the Director of the Bureau of Meteorology has never seen in his whole career.

"There is no infrastructure that can be developed that can protect you against catastrophic events that take out three pieces of infrastructure."

Bureau regional director John Nairn said the state was hit by an extremely vigorous front connected to a very powerful low, with strong wind gusts bringing down trees and towers.

He said Adelaide was in a lull but it would be short-lived before the system reintensifies today.

"We've only seen half the rain we've expected to see so far," he said yesterday. "We're expecting quite significant falls tonight."

Conditions are expected to ease later today with better conditions tomorrow but Nairn said there would be further rain on Sunday, Monday and Tuesday.

- news.com.au, AAP