Residents from the small Adelaide Hills town of Echunga have evacuated to the local football club, where volunteers are cooking food and offering support, as authorities attempt to stop a private dam from bursting.
According to the SES, there is a threat to people's safety and residents have been warned to prepare for flooding and follow their emergency plan.
Echunga is a small town in the Adelaide Hills, about 34 kilometres south-east of Adelaide.
The dam is located on farming land between Marianna St and Churchill Road.
If the path is clear, the SES has urged people to relocate to the home of family and friends outside the warning area, or to the Echunga Football Club.
SES state duty officer David O'Shannessy told ABC Radio Adelaide that the dam, located less than 500 metres upstream from the town of Echunga, holds about 10 megalitres of water.
On its website, the SES said it was made aware last night that the private dam was showing signs of structural failure in its wall.
Mr O'Shannessy said there had been a deterioration in the dam wall's integrity overnight.
"However, we are doing everything we can to mitigate that risk," he said.
"We're doing controlled releases of water, we've got engineers involved, we've got other experts involved."
He said the affected area encompassed most of the central township of Echunga, including about 60 properties.
"If you are in the area you just need to follow any emergency plan you might have, prepare your home for flooding, but really we're just asking people to move out of the area," he said.
"We don't think it's inevitable that this will happen but we just want people to be prepared that if it were to happen they're just not in the area."
The SES said floodwaters might rise rapidly and were likely to be fast moving, warning people not to walk, drive or ride through floodwater.
A number of roads are closed, including Aldgate-Strathalbyn Road at Echunga Road, Echunga Road at Aldgate-Strathalbyn Road, Battunga Road at Meadows Road, Strathalbyn at Sophia Street and Church Hill Road at Old Mount Barker Rd.
Mr O'Shannessy said the Adelaide Hills had experienced "quite a wet season" over winter and the catchments were soaked.
"And so a lot of the water that would normally be soaked up by the ground is just now going to run off, so the dams are very full up there," he said.
"So that combined with quite wet ground, it appears just in this case that this private dam's had a shift and that's started a couple of shifts.
"So I think it's just a really unfortunate series of events as an isolated event but I think we have had enough rainfall over the winter to see this happen."
Marc Boord owns a business close to the dam on Marianna Street "pretty much in the firing line if it does go".
He said he received a knock on the door about 5:20am saying they needed to be ready to leave.
"The dam is moving — it's apparently bubbling — which means the earth is moving under it," he said.
"From what we've been told and the word from this morning was it's pretty much going to happen, they just don't know how and when basically."
He said he had been told a siren would sound if the dam had collapsed or was about to.
Camilla and Renzo Gaetan and their young son Luca were among the Echunga residents who evacuated this morning.
"We're pretty hopeful that because we are uphill it wouldn't reach us," Mrs Gaetan said.
Mr Gaetan said they prepared for the worst but were hopeful "it doesn't pan out that way".
"There's not much we can do about it, we grabbed what we thought we'd need and if it turns out for the worse we'll just have to deal with it when it happens," he said.
"But we're optimistic that it's not going to turn out that way."
Echunga Uniting Church minister Matthew Carratt was at Echunga Football Club this morning with a group of volunteers providing refreshments for those who have evacuated.
"When we heard about the news last night, this morning we've mobilised a few [volunteers] to come and put some soup on and some sausages if needed later on for those here at the footy club who have nowhere to go," he said.
While Mr Carratt does not live in the area, the church is located in the emergency warning zone, and he was keen to offer his support.
"It's a small community, everyone bands together," he said.
He said the uncertainty was challenging for residents.
"It's a bit like waiting in a hospital, and unsure what's going to happen and when," he said.
