Military helicopters conducted a massive search for scores of missing people while thousands of people fled their homes in the deadliest episode yet of the flood crisis to hit Australia.
A major rescue operation was launched after a wall of water ripped through Queensland's Lockyer Valley on Monday, tossing cars around like toys.
At least 10 people were killed and last night 78 people were still unaccounted for almost 24 hours after the flash flood – which saw building windows explode with the tsunami-like force of the torrent.
The latest victim was a four-year-old boy who fell into the water and drowned as he and his family were being moved to safety. Authorities had grave fears for at least 18 of the missing.
The valley funnelled rain from a freak storm – up to 6in fell in half an hour near Toowoomba city – into a raging river that formed a path of destruction, ripping houses from their foundations.
Entire families sought refuge on roofs and were being airlifted to safety yesterday.
Leroy Shephard, who lives in the town of Grantham, east of Toowoomba, was inside his home when the flood struck. "You could feel the whole house just pop up off its stumps, turn around, and go – for a 100 meters (330 feet) or something down my backyard," he told Australian Broadcasting Corp.
He and his family spent five hours on the house's roof waiting for the waters to drop. "It's not a good feeling having the floorboards under your feet just ripple, the whole house just ripple and crack, and watching rooms just disappear," he added.
The torrent slowed and spread out as it moved downstream toward the state capital of Brisbane, Australia's third-largest city with two million people, but the Brisbane River overflowed its banks yesterday and officials said thousands of houses in dozens of low-lying neighbourhoods and parts of downtown could be inundated.
Fearful residents queued for up to four hours outside emergency services depots to get sandbags to try to protect their homes, and shoppers stocked up on bottled water, milk and fuel.
The violent surge near Toowoomba escalated Australia's flood crisis in Queensland state and brought the overall death toll to 20. Until then, the flooding, which began before Christmas, had unfolded slowly as swollen rivers burst their banks and inundated towns while moving downstream toward the ocean.
State premier Anna Bligh said five children were among those killed in the latest incidents and that many of those still stranded or unaccounted for are families and young children.
Emergency services plucked more than 40 people from houses isolated by the torrent that hit the Lockyer Valley, and thousands moved out or were being evacuated.
In one small community, Forest Hill, the entire population of about 300 was airlifted to safety in military helicopters.
The search and rescue effort was hampered by thunderstorms and more driving rain, although the bad weather eased during the day.
Officials said 40,000 homes in Brisbane could be affected by flooding, with more than 6,000 of these due to be inundated. The flood peak is expected on tomorrow.
By last night streets were largely deserted as families living in some 80 suburbs moved to evacuation centres in the city and neighbouring Ipswich, where a third of the town was expected to be submerged as water levels reached a peak overnight. Rising waters had cut off one of the main routes out of the city while the sheer numbers of people attempting to drive away had led to others becoming gridlocked yesterday afternoon.
Those staying were facing the coming ordeal without electricity as energy firms shut off the power to riverside areas ahead of the expected deluge and authorities were urging residents not to panic.
The city is protected by a large dam built upstream after floods devastated downtown in 1974 but the reservoir was full and officials had no choice but to release water that would cause low-level flooding, Mayor Campbell Newman said.
The alternative was a much worse torrent.