The South Australian regional city of Port Augusta is the latest to suffer a heavy downpour, receiving more than a quarter of its annual average rainfall over a few hours last night.
The rain started about 8pm and dropped 59 millimetres, cutting National Highway 1 which runs through the city and trapping several vehicles.
Jonathan Webb was on his way home from his brother's house when he saw cars stuck in the floodwater and he and a friend sprang into action, pulling 22 cars to safety.
"When we first pulled up and asked the first car we saw if they needed a tow, they looked pretty sad," Mr Webb said.
He continued further down the road past a takeaway shop where he saw even more cars had been caught in the flash flood.
"When I walked out to have a look at more of the cars, I was in hip-deep water," he said.
SES chief of staff Graeme Wynwood said most of the impact was general damage to houses.
"We had a call for about 80 tasks that were attended, there were five swiftwater rescues, so vehicles that were trapped and people that were trapped in fast-running water."
'Drowned rat'
Mayor Brett Benbow said water reached the doors of cars on the main shopping strip.
"I've lived here all my life and I've never seen rain come down that hard and that long," he said.
Matty Ivanovic was driving through Port Augusta when she was caught up in flash flooding on the highway.
"When you get out of the car, the water is up to your hips, and I'm like a drowned rat," she said.