South Australia braced for a second night of severe weather Thursday, with tens of thousands of homes still without power after ‘catastrophic’ storms knocked out supply to the entire population.

The total blackout caused chaos and widespread damage was reported, as authorities warned of more wild conditions to come including floods, high winds, heavy rain and surging tides.

The state's premier Jay Weatherill said ‘twin tornadoes’ had hit northern areas, where 40,000 households were expected to remain without electricity for a couple more days.

‘We have experienced some weather conditions that have not been seen before in this state,’ he told a press conference in the state capital Adelaide.

‘Twenty-three transmission towers have been ripped out of the ground by the force of this storm event.’

Some 80,000 lightning strikes were recorded late Wednesday, hitting infrastructure and bringing down electricity lines.

‘We remain in the middle of this event and there also is a significant way to go,’ Weatherill warned.

South Australia -- about one and a half times the size of France and with a population of 1.7 million -- lost power on Wednesday afternoon after severe thunderstorms struck with destructive wind gusts of up to 140 kilometres per hour (87 mph), torrential rain and large hailstones.

Trees were felled, roofs ripped out and thousands of homes and business lost power.

Cars were gridlocked on flooded roads as traffic lights failed and mobile phone coverage was disrupted.

‘We now have over 90 percent of power restored to homes,’ Weatherill said. Thursday began with 75,000 homes without power, but 35,000 were expected to have electricity restored during the day.

However heavy industries, such as minerals giant BHP Billiton's Olympic Dam copper and uranium mine and Arrium's Whyalla steelworks which Weatherill said drew ‘very substantial amounts of power’, faced a longer wait.

The Bureau of Meteorology termed it a once-in-50-years event and issued a new severe weather warning for later Thursday as an intense low-pressure system crosses the state.

Gale-force winds were again predicted to reach speeds of 75 kph and gusts of up to 120 kph with the Eyre peninsula risking gusts up to 140 kph.

Weatherill said there were no reports so far of serious injuries or deaths.

Federal Energy Minister Josh Frydenberg said ‘serious questions’ would be raised about how a major state's entire electricity supply could be knocked out by severe weather.

But Weatherill accused Frydenberg of ‘playing politics’ with an unfolding crisis and said it could have happened anywhere.

‘This would have happened whatever the system looked like in whatever state had this damage occurred in another place,’ the premier said.

‘This is a catastrophic natural event which has destroyed our infrastructure.’