The Royal Australian Air Force C-27J Spartan was scheduled to depart Edinburgh on Monday morning as the first flight in a mission to deliver 20 tonnes of supplies including fresh produce, meat, dairy, frozen food, and toilet paper.

Two flights a day across the week will deliver the supplies to Coober Pedy Airport.

South Australia’s far north is bracing for up to 200mm of rain in the coming days.

BoM meteorologist Vince Rowlands told InDaily the rains will begin in the north west pastoral regions before extending east overnight, with intense thunderstorms possible.

“Considering we’ve already had quite a lot of rainfall in that area, there is a reasonable risk of localised flooding so have issued a floodwatch warning [for the North West and North East Pastoral Districts],” he said.

The floodwatch warning covers Marla, Coober Pedy, Ernabella, Oodnadatta, Amata and the area around Emu Junction.

It follows the State Government declaring a major emergency on Friday in response to storms that hit the northern Eyre Peninsula last weekend and then the Lower Eyre on Thursday morning.

The storms have cut access to a 250km strip of the Stuart Highway between Glendambo and Coober Pedy and severed the rail link from Adelaide to Darwin and Western Australia.

Crews continue to work on reparing the flood damaged Stuart Highway. Photo: Department for Infrastructure and Transport/LinkedIn

Coober Pedy opal miner Justin Freytag told InDaily the town has been running low on fuel and fresh food since roads to the north, south and east were cut off by up to half a metre of flooding last week.

“It’s deep water that is dangerous, with no line markers — one truck drove off the road last week,” he said.

“So its a lot of tinned food for us right now, but you get used to that living in the bush.”

Freytag, the chair of the Coober Pedy Miners Association, added that the wet weather had slowed up opal mining as access roads get bogged down, but worried that further rains could significantly worsen the situation.

“If we get another 100mm tonight we’re in big, big trouble, the ground is soggy already so it doesn’t take much,” he said. “If the mine floods, that sets us right back and we’d have to fish out the mining equipment and repair it. That would be a horror so fingers crossed.”

Coober Pedy Council administrator Tim Jackson told InDaily he was expecting two planes to arrive in the town on Monday, and that there had not been any panic buying and the town residents are remaining calm.

“The thing is we don’t know how long this is going to go on for, so getting these supplies in is critical,” he said.

SA Police Assistant Commissioner Ian Parrott said several heavy vehicle operators has been reported after breaching the road block on the Stuart Highway.

The Department for Infrastructure and Transport said the timeframe for reopening the Highway is “unknown” because “the road surface near Glendambo is still inundated by water, and more rain is forecast … throughout the coming week”.

Federal Minister for Finance Simon Birmingham told the ABC on Monday that the Commonwealth is ready to provide financial assistance to a “small number of cases”.

“If the requests are made as I expect they will be, there is some emergency financial assistance that can provide as disaster recovery payments to individuals who were affected,” Birmingham said.

The State Emergency Service said it expects the Australia Rail Track Corporation will finish repairing the damaged train lines by February 14 to 17.

State Emergency Service chief officer Chris Beattie expressed concern the forecast for more rain will add to the problem.

“A flood watch and severe thunderstorm warning is in place and we do have concerns that this next front could lead to additional road, rail and property damage, exacerbating supply chain disruptions including food supplies for some communities, as well as increased economic impacts from further delayed freight,” he said in a statement late on Sunday.

The BoM forecasts that the heavy rains should contract northwards by Wednesday.

Rowlands said the “rare and unusual” heavy rains were being driven by an infeed of tropical moisture prompted by the La Nina weather system, and that the last time the far north saw daily rainfall above 150mm was in 2015.