Efforts had swung to protecting property, with people in the path of the fire evacuated.
On the Spencer Gulf, towns near the coastal town of Port Germein were threatened by another huge blaze.
In Victoria, residents of the Northern Grampians towns of Wartook and Heathvale were battened down ahead of fires sweeping through the region. Earlier in the day they had been told it was too late to leave and to prepare for the flames. Properties were reported destroyed near Wartook.
People fled Halls Gap and other towns, but police yesterday confirmed a person had been found dead at nearby Roses Gap.
Emergency warnings were late yesterday also in place for Cherrypool, Laharum, Heathvale and Glenisa. Residents of the towns and surrounding settlements were advised to flee yesterday morning.
Elsewhere in the state more than 40 fires were out of control. In NSW, more than 10 outbreaks had also to be controlled late yesterday.
In Adelaide and Melbourne, where temperatures have remained in the 40s for most of the week, authorities were struggling to cope with a spike in heat-related problems, including a large increase in hospital admissions. Hundreds of people have been treated.
Electricity supplies have been hit. SA and Victoria experienced their highest demand since the 2009 heatwave that sparked the Black Saturday fires and power cuts have affected tens of thousands of homes and businesses.
In Melbourne, trains have been travelling 10km/h below normal speeds to lower the risk from rail damage caused by the heat, delaying services.
The Climate Council warned this week worse was in store for future summers as climate change continued to bite, creating hotter, longer and more frequent heatwaves.
The council said last year was Australia's hottest on record, extending long-term trends that had seen a rise in severe fire weather over the past 30 years and extending fire seasons. It said hazard reduction burning in the Sydney region would need to increase two to five times to counter the threat.
The number of professional firefighters would need to double by 2030.
The council warned that communities, emergency services, health services and other authorities needed to start planning now for more heat and the increasing severity and frequency of extreme fire conditions.
The warning has been echoed by researchers at RMIT University's Climate Change Adaptation Programme, who say the "urban fabric is already clearly under stress" from the present heatwave.
Research fellow Jane Mullett and Professor Darryn McEvoy, writing in The Conversation, said much had been learned from the 2009 heatwave, which led to the deaths of 374 people in Melbourne and killed a further 173 in bushfires.
Studies showed key urban infrastructure and services were hit hard: power failures, problems with the transport network, and extra pressure on emergency services from victims of heat and fires.
Rail lines buckled, causing shutdowns, and power failures trapped hundreds in the underground rail loop and cut traffic signals on city roads.
Mullett and McEvoy said lessons had been learned and changes made to emergency management procedures. Councils introduced new heatwave plans, which swung into action this week.
The Victorian Government launched heatwave strategies - including community awareness programmes and designated cool spaces - and new media campaigns on surviving heatwaves. A health alert system warns local governments, hospitals, and health and community services of impending heatwaves.
But Mullett and McEvoy said more was needed: "While lessons have clearly been learned from the 2009 heatwave it is clear that future climate change, and more severe heatwave events, will require longer-term planning.
"That means an extensive upgrading of infrastructure if our cities are to be made resilient in the face of climate change and ever-increasing urban populations.
"This may well include thinking that goes beyond current incremental changes to more radical transformational change in how our cities function."
