While river communities are facing inundation from flooding, other parts of South Australia are now bracing for the state's first day of catastrophic fire danger since the national danger rating system was revamped.
Country Fire Service (CFS) crews are on high alert across four of the state's districts, water bombers have been deployed in preparation for potential bushfires, and a giant aerial tanker will fly in from Victoria early tomorrow.
Saturday is forecast to be a day of catastrophic fire danger in the Lower Eyre and Yorke Peninsula districts, with extreme fire danger in the Mid North and Eastern Eyre Peninsula.
The fire threat in the Mount Lofty Ranges was initially also listed as extreme, but has since been reassessed as high.
Strengthening hot, northerly winds are forecast to push temperatures into the mid-30s ahead of a gusty westerly change, which could extend the risk.
"If a fire takes hold under the forecast conditions tomorrow, it will be fast moving, it will be dynamic, it will be very difficult for ground and aerial resources to control, and it will present a clear risk to lives, property and livelihoods in those communities," CFS chief officer Brett Loughlin said.
Earlier this year, fire authorities across the country agreed to a new national fire danger system, retaining the catastrophic and extreme ratings but streamlining and standardising the categories.
"This is the first catastrophic fire danger forecast we've had for this fire season … the catastrophic fire danger represents the highest risk presented to communities," Mr Loughlin said.
"It is really important that people take the remaining time today to prepare before this weather tomorrow. It's important that you move high-value machinery and stock to low-fuel areas.
"It's important that if your plan is to leave and leave early that you are ready to enact that tomorrow morning before any fire threatens your safety."
Late rains and harvest add to fuel load
Fuel loads are much higher than they typically would be at this time of year.
"The late harvest, combined with those significantly wetter-than-average conditions in much of South Australia, means there is more fuel out there than normal," Mr Loughlin said.
The Bureau of Meteorology has said a combination of heat, wind strength and low humidity would also elevate the fire risk.
"On Saturday, we are forecasting a significant increase in winds and temperatures across the state ahead of a trough and this will see a spike in the fire danger," senior meteorologist Jon Fischer said.
"The risk period will extend into the evening in some areas."
Emergency Services Minister Joe Szakacs said that while River Murray communities were battling inundation caused by extremely high flows, emergency services were equipped to respond to different threats.
"Notwithstanding the very significant water we are seeing through our river communities, tomorrow we are seeing a widespread number of communities that will be impacted by either extreme or catastrophic fire danger ratings under our updated, nationally consistent Australian fire danger rating system," he said.
"A large aerial tanker has been secured tomorrow and will be positioned ready for deployment at the RAAF Edinburgh air base."
The CFS has urged against activities such as harvesting, welding, angle grinding and moving machinery and vehicles through paddocks and long grass.
It has advised those in affected areas to stay across the CFS website and ABC Local Radio.
