Thunderstorms have lashed Roxby Downs in outback South Australia, flooding roads and several properties in the town.

The first storm hit about 7:30pm on Thursday and another front swept through early Friday.

More than 85 millimetres of rain fell at the airport.

Service station worker Terry Luckett says it has not rained so hard in at least 20 years.

“Quite used to Queensland weather and it sort of resembled that for probably two or three hours there. It just constantly was coming down, quite heavy,” he said.

“On and off I’ve been here since 1990, so [in] 20 years this is the first time we’ve seen it like this.”

Vicky Visser owns a cafe in Richardson Place which has been flooded.

“I pulled up at the shop and literally had to wade through knee-deep to get into the shop,” she said.

“We have had all night in clean-up so the coffee machine is on and the food is getting hot and the sandwiches are getting made so we’re going to be, hopefully, all systems go, albeit a little rearranged.”

More than 85 millimetres has also been recorded at nearby Andamooka.

Dams are overflowing and houses have been flooded.

Supermarket owner Cassandra Lion says the water rushed down the main street.

“One gentleman we found this morning on the roof of his four-wheel-drive that’d been spun around 180 degrees by a surge of water and he was trapped there,” she said.

“At one stage the water was actually halfway up his front windscreen.

“There are a couple of houses across the creek from where I am at the moment that were under water.”

Another Andamooka resident Kyle Christensen says it is the best rain he can remember since 1975.

“We’ve had so many years of drought and that that we’ve been probably looking for this rain and then all of a sudden instead of it raining a normal rain it just buckets down,” he said.

Senior forecaster Peter Webb says the rain is continuing.

“We still currently have a severe thunderstorm warning for an area covering Marla from Coober Pedy down to just north of Port Augusta and up to Moomba, so that wedge of area up in the north-east pastoral, including the northern parts of the Flinders, can expect further thunderstorms with heavy falls during the morning,” he said.

More than 60 millimetres fell at Leigh Creek in the 24 hours to 9:00am and 33 millimetres fell at Woomera.

Crop hopes

In other areas of the state, farmers are considering an early start to seeding because of this week’s rain.

Many are already reporting good soil moisture.

Rural consultant Barry Mudge says farmers need to weigh up how they will manage to avoid frost damage during the winter months and any early heat in spring.

He says some Mallee farmers have already planted feed crops but farmers usually wait on good rains around Anzac Day.

“My feeling from talking to a lot of farmers is they’re saying, ‘yeah, perhaps we can come maybe a week earlier than we’re used to,’ but a lot of people are saying, ‘look, we need to get through to at least April 20,’ and even then it’s only going to be done as a bit of a risk management tool,” he said.