Authorities are warning South Australians to expect extreme weather and bushfires that could be difficult to predict as temperatures soar this weekend.

Key points:

  • The CFS has warned South Australians to be on high alert
  • The Mount Lofty Ranges are expected to be at extreme bushfire risk
  • Less reliable bushfire and weather modelling this year could add to the danger

A maximum of 39 degrees is forecast in Adelaide today.

But the Country Fire Service (CFS) is most concerned about Sunday, when the mercury is expected to reach 41 degrees.

Authorities are also worried about less reliable weather and bushfire models as a result of the current La Niña weather pattern.

CFS chief officer Mark Jones urged South Australians to limit “risky outdoor activities” and said he expected it to be a “testing weekend for South Australia”.

“We’re also concerned that it’s a holiday weekend, and lots of South Australians will be moving around the state.

“We, of course, are aware that they could be entering areas which are a high fire risk.”

A firefighter with a fire hose sprays a smouldering tree stump near Lucindale in South Australia’s south-east earlier this month.(ABC News: Bec Whetham)

He said people living in higher-risk areas should prepare their homes for the risk of fire, and have a plan.

“For those of you who live in bushfire-prone areas, have a plan, know what you’ll do now, before fire threatens your home,” he said.

“Combustible items around your house — just don’t take the chance of them contributing to a fire.”

The old Avenue Store that was destroyed by a fire near Lucindale earlier this month.(Supplied)

Mr Jones said both weather and bushfire modelling was more difficult, and less reliable, in La Niña years — which had already affected firefighters’ ability to anticipate the behaviour of fires this season.

“They’ve been less than accurate this season in two significant fires — one in Yumali and one in Blackford, in which the fire behaviour considerably exceeded that that we model,” he said.

“We expect that trend to continue for the rest of this summer.”

Wet spring, dry summer create bushfire fuel

South Australia has experienced more moderate weather and a less extreme bushfire season so far this year, compared with the devastation of the 2019-2020 season.

A blaze at Cuddlee Creek was one of 200 fires that broke out in catastrophic conditions on December 20, 2019 — the same day that fires broke out on Kangaroo Island, which flared disastrously in early January.

Between them, the fires killed three people, destroyed about 140 homes and devastated native vegetation and wildlife.

The ruins of a house after a bushfire ripped through on Kangaroo Island. January 4, 2020.(Supplied)

Mr Jones said South Australians were grateful for the wetter weather in the lead-up to this year’s bushfire season, but that the rain had spurred the growth of a lot of combustible material.

“Even though we had a wet spring, which gave us a lot of grass growth and undergrowth flourished, we’ve had a very dry period since,” he said.

“Which means that all of that grass that grew is essentially fuel — fine fuel — waiting for ignition sources.

Mark Jones says South Australians should be on alert for bushfires and extreme weather this weekend.(ABC News)

Mr Jones said the Mount Lofty Ranges in the Adelaide Hills would be at extreme risk of bushfire this weekend.

“It’s a very large area, which incorporates almost all of the Mount Lofty Ranges which is at risk,” he said.

“When significant high temperatures combine with winds, especially when everything’s already dry in the state, the risk is considerably heightened.”

Mr Jones urged everyone to check the CFS website for information.

Emergency alerts are also broadcast on ABC Local Radio.