Two people have died in a major bushfire north of Adelaide and there are unconfirmed reports of a third death, South Australian Premier Jay Weatherill says.
Fire crews are working through the night battling the blaze, which is burning out of control.
One body was found in a paddock and a body was also found in a car in north east Adelaide.
The unconfirmed report is of a death near Freeling after a car was reported to have hit a tree.
"Our priority will be to access these sites safely and, of course, to notify the next of kin," Mr Weatherill said.
Mr Weatherill also confirmed at least three people who were helping fight the fire have been taken to the Royal Adelaide Hospital with severe burns.
We also know that there are many homes, sheds, crops and livestock losses due to the active fire front, I can't give you exact figures at this point," Mr Weatherill said.
Properties in Tarlee, Freeling and Kapunda have been affected by the blaze, which had burned more than 85,700 hectares on Wednesday.
An emergency warning on Wednesday night said the main fire activity was around Kapunda, and there remained potential for structures to be impacted.
The fire front was about 40 kilometres wide.
CFS chief officer Greg Nettleton said the total perimeter of the fire was 211 km.
"So if you can imagine a continuous fire line from Adelaide to Port Pirie, that's the perimeter of the fire that we've got to contend with over the next few days," he said.
"Now some of that perimeter will be fairly easy to extinguish and make safe, but there will be other areas of that perimeter that will be quite difficult as it gets into more and more difficult timbered country."
The blaze started at Pinery about midday on Wednesday and travelled 50 kilometres in just four hours. The cause of the fire is still unknown.
Mr Weatherill said there were five rapid assessment teams on the ground looking at property damage and stock damage.
Relief centres have been set up and about 1,000 people are working to fight the blaze including 70 appliances on the ground along with 340 volunteer firefighters.
Additional firefighting strike teams are expected from Victoria on Thursday morning.
SA Power Networks said outages had impacted about 22,000 customers throughout the day.
Mr Weatherill urged anyone requiring medical treatment to attend one of the relief centres or the closest medical facility.
One school was evacuated on Wednesday, and Mr Weatherill said at this stage many schools would potentially be closed on Thursday.