Around 7,000 homes across South Australia are without power after a storm damaged infrastructure.
Whyalla is the worst hit area with about 5,000 homes losing electricity.
More than 120,000 lightning strikes were recorded yesterday across the state.
SA Power Networks spokesman Paul Roberts says crews are working to restore power which could take as long as three days.
"It's going to be well into the weekend and probably early into next week before we get everyone back and supplied," he said
"It's going to take us well into this morning and probably early afternoon to assess the damage and prioritise the repair work... we'll be doing some repairs during that time."
Whyalla mayor Jim Pollock says the storm came through fast.
"It's very widespread from one end of Whyalla to the other," he said.
"Some very old trees [were] picked out of the ground like toothpicks, landing on fences and properties.
"The clean up has started and it will take a few weeks to get to the bottom of it, I think."
© ABC 2012