Authorities on Thursday confirmed that at least 33 people were treated for minor fire-related injuries and 11 properties were damaged by more than 45 bushfires amid catastrophic conditions on Wednesday.
"I think people are just in a bit of shock reacting to the situation," the Mayor of the hardest-hit Yorke Peninsula Darren Braund told the Australian Broadcasting Corporation (ABC).
Residents around Adelaide, the state's capital city, on Thursday awoke to the city blanketed in smoke.
The Country Fire Service (CFS) issued a "watch and act" message for nine regions, warning residents that they are under threat from uncontrolled fires.
"If you are not prepared, leave now and if the path is clear, go to a safer place," it said.
The fires began on Wednesday when temperatures across the state soared above 40 degrees centigrade.
They were exacerbated by strong winds, which accelerated the speed at which the fires moved.
On Thursday, a cool change dropped the temperature in Adelaide from a record-breaking 41.6 degrees centigrade on Wednesday to about 21 degrees centigrade.
The fires in SA are the latest in an early start to the Australian bushfire season.
Four people were killed by bushfires in New South Wales (NSW) earlier in November which also destroyed more than 500 homes and burnt more land than any other fires in the state in the last 25 years.
A total fire ban was put in place in Victoria on Thursday with the temperature forecast to top 40 degrees centigrade in Melbourne for the first time in November since 1997.