A trifecta of dangerous weather conditions has prompted extreme to catastrophic danger alerts to be issued for parts of South Australia.
The Country Fire Service has warned Friday will be "one of the most significant fire weather days in several years".
Temperatures are forecast to sore into the mid-40s in some parts with strong winds and dry lightning adding to the fire risk.
The CFS has declared catastrophic fire danger ratings for the mid-north, Flinders, Yorke Peninsula, Riverland and eastern Eyre Peninsula districts.
Extreme fire danger ratings have been issued for the Mount Lofty Ranges, north east Pastoral, west coast, upper southeast and Murraylands regions.
Any fires that did start would be "incredibly difficult" for firefighters to control, CFS chief officer Brett Loughlin said.
"The dry lightning creates a real risk of fire starting anywhere these thunderstorms occur, unfortunately the forecast is a broad area of dry lightning and thunderstorm activity," he told reporters on Thursday.
SA authorities say strong winds may prevent the use of aerial fire fighting assets on Friday. (Russell Millard/AAP PHOTOS)
The service secured a large air tanker from the Commonwealth to help with firefighting operations, but Mr Loughlin stressed conditions could hamper its use.
"I want to stress, the forecast winds tomorrow are such that there is likely to be times when an aircraft will be unable to safely fly and fight fires," he said.
"It is crucial that people do not rely on firefighters and aviation assets to save them."
Residents were urged to have a bushfire survival plan in place and to understand what they would do in the event of an emergency.
Electricity outages are also possible as equipment is set to disconnect to minimise the risk of sparking a blaze.
"Those outages may also be extended in regional and remote areas if crews are stretched by managing safety in severe conditions and responding to the trifecta of weather conditions," SA Power Networks corporate affairs head Paul Roberts said.
After Friday's heat, temperatures will dip to the low to mid 20s across much of SA on Saturday with Adelaide forecast to have up to 60 mm of rain over the weekend.
A Total Fire Ban in place tomorrow, Friday 8 December - Lower Central West Plains, Southern Riverina, Northern Riverina & South Western areas. Very hot, dry and windy conditions forecast across parts of NSW. Know what you'll do if fire threatens. — NSW RFS (@NSWRFS) #RFS https://t.co/R9tDns8ts6 pic.twitter.com/lNQEoHbxsEDecember 7, 2023
In NSW, a total fire ban has been issued for the lower central west plains, southern Riverina, northern Riverina and south western regions due to the hot conditions.
NSW residents are entering their third day of above-average temperatures on Friday, with the heatwave not expected to ease until next week.
Parts of Queensland, West Australia, the Northern Territory and ACT have also copped soaring temperatures that are expected to intensify over the weekend.
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