Severe weather has cut electricity supplies and brought down trees across parts of South Australia, keeping emergency crews busy.
As many as 15,000 homes and businesses in Adelaide, the Adelaide Hills, mid-north and south-east have lost power in high winds.
SA Power Networks said it might take hours yet to get those properties all reconnected.
It said there had been 28,000 properties without power at some stage since midnight.
The State Emergency Service had to deal with its own loss of power.
Duty officer Andrea Geytenbeek said they switched to back-up power as they managed emergency calls across the state.
"Within state headquarters we're experiencing one (blackout) at the moment so we've gone to our contingency planning. None of the [emergency] units have been affected," she said.
The weather bureau said gusts peaked at 98 kilometres per hour at Minlaton on Yorke Peninsula during the morning but it was forecasting gusts peaking at 120 kph during the afternoon.
It said the weather system passing over SA was the most powerful of the winter and could produce some snow.
The bureau said up to 100 millimetres of rain might fall around the Mount Lofty Ranges and the mid-north by Monday.
© ABC 2013
14:30 EST The Bureau of Meteorology has revised down its prediction of an El Nino weather event developing later this year.