IPSWICH: Eight people died and 72 were missing on Tuesday after giant flash floods smashed through an Australian town like an “inland tsunami”, suddenly escalating a widespread flood crisis.

Queensland premier Anna Bligh said the death toll would rise “potentially quite dramatically” after fast-running torrents devastated Toowoomba and other mountainside towns, sweeping away cars and leaving survivors clinging to trees.

TV images showed streets turned into churning rapids dotted with floating cars, some with people sitting on top, while elsewhere residents were forced on to rooftops as waters lapped the awnings.

“Mother Nature has delivered something terrible in the last 48 hours but there’s more to go and our emergency people are more than up to that task,” said Bligh, warning that whole families were unaccounted for.

“This is going to be I think a very grim day, particularly for the people in that region, and a desperate hour here in Queensland.”

Bligh said she had grave concerns for the missing as rain and washed-away roads frustrated rescue teams and left them unable to reach stranded communities by land or helicopter.

Four of the dead were children, some of them swept away in cars driven by their mothers. A man and a younger male died in Murphy’s Creek near Toowoomba, 125 kilometres west of Brisbane in the Great Dividing Range.

Toowoomba mayor Peter Taylor said the town was struck without warning after two normally innocuous waterways suddenly overflowed.

“Torrential rain over a very short period of time came down two major creeks through the middle of the city which are normal quiet drainage ways, and people had no warning at all,” Taylor told the Seven Network.

“It was just unprecedented. Some people are saying an inland tsunami, and I think that probably sums it up really.”

Brisbane, the Queensland state capital, was itself under threat from a rolling flood peak while other people were forced to flee their homes and 1,700 were cut off in the neighbouring state of New South Wales.

Nineteen people have now died in flooding across Australia’s northeastern coal-mining and farming zone after weeks of rain blamed on the La Nina weather system, which has also dumped heavy snow on the northern United States.

The flash floods were caused by torrential rains falling on saturated ground, after overflowing rivers afflicted a huge area the size of France and Germany combined at huge economic cost.

Disaster coordinator Ian Stewart said he had serious concerns for the small Queensland town of Grantham, where three of the latest victims died and where dozens of residents are thought to be stranded.

“Grantham is going to be, in my view, just a disaster in terms of the number of homes that have been damaged or destroyed and we’re waiting on confirmation of potential extra loss of life,” Stewart said.

Federal MP Ian MacFarlane described dramatic scenes in Toowoomba as the flash flood deluged the town before subsiding within three hours, leaving scenes of destruction and people dead in their cars.

“We’re just seeing building after building, the water rushing in and blowing the windows out,” MacFarlane told Sky News. “Cars that were parked in the car parks were just lifted up and went bobbing down the street.

“I’ve lived in Toowoomba for 20 years and I’ve never seen anything like that. This is flooding without precedent in Toowoomba,” he added.

Four military helicopters were sent to join the emergency effort but rescuers were badly hampered by continuing heavy rains in the Lockyer Valley region.