Residents in parts of Brisbane, Australia, have been urged to leave their homes after the city's main river burst its banks, threatening to inundate dozens of low-lying neighbourhoods with water.
Other residents queued for up to four hours outside emergency services depots on Tuesday to get sandbags in a bid to protect their homes and shoppers stocked up on bottled water, milk and fuel after floods which have devastated Queensland in recent weeks threatened to reach the city. People living in at least three suburbs were asked to prepare their homes and then go and stay with friends or family on higher ground.
Queensland state premier Anna Bligh said about 9,000 homes in Brisbane could be badly affected and tens of thousands more could have floodwaters enter their back yards. The flood peak is expected on Thursday.
Meanwhile, military helicopters searched for scores of people missing after a tsunami-like wall of water ripped through Queensland state's Lockyer Valley, tossing cars like toys in the deadliest episode of the area's flood crisis.
At least 10 people were killed and 90 still unaccounted for almost 24 hours after the flash flood hurled untold millions of gallons of water down the valley on Monday, Ms Bligh said. Authorities had grave fears for at least 18 of the missing, she said.
The valley funnelled rain from a freak storm - forecasters estimated up to six inches fell in half an hour near Toowoomba city - into a stream that formed a path of destruction, lifting houses from foundations. The torrent slowed and spread out as it moved downstream towards Brisbane, Australia's third-largest city, which is home to two million people.
"This is a truly dire set of circumstances for the people of Queensland, with more flooding to come," said prime minister Julia Gillard.
The violent surge near Toowoomba on Monday escalated Australia's flood crisis in Queensland state and brought the overall death toll to 20. Until then, the flooding had unfolded slowly as swollen rivers burst their banks and inundated towns while moving downstream toward the ocean.
Emergency services officers plucked more than 40 people from houses isolated overnight by the torrent that hit the Lockyer Valley and thousands were being evacuated. In one small community, Forest Hill, the entire population of about 300 was airlifted to safety in military helicopters, Ms Bligh said.
As Tuesday progressed, the death toll rose from eight to 10 and Ms Bligh said officials held grave fears for 18 of the 90 people missing.