The blaze at Yumali near Coonalpyn destroyed about 4800 hectares but warnings have now been reduced to an advice message.
The Country Fire Service said the fire was caused by SA Power Networks infrastructure and SAPN was working with fire cause investigators.
CFS crews, along with farm fire units, Department of Environment and Water (DEW) crews and earthmoving machinery work overnight to control the fire.
CFService state duty commander Yvette Dowling said extra growth in areas that were yet to be harvested increased the risk of fast-moving fires.
“The fire travelled with such speed that it was not safe for us to put our trucks in front of it in an attempt to extinguish,” Dowling said.
“The fire burned with such ferocity that at times it was difficult for our firebombers to attack the flames.”
At the height of the incident, a CFS four-wheel drive collided head-on with a private vehicle on the fireground.
Two people suffered minor injuries.
The CFS air fleet completed 48 drops onto the fire to bring it under control.
“This fire has given us an early reminder that, even though we have had recent rainfall and cooler conditions, there is still a great potential for large-scale fires,” Dowling said.
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