BRISBANE, Australia — Military helicopters searched Tuesday for scores of people missing after a tsunami-like wall of water ripped through an Australian valley, tossing cars like toys in the deadliest episode of a weekslong flood crisis.
At least nine people were killed and officials held grave fears for 66 others still missing almost 24 hours after the flash flood hurled untold millions of gallons of water down Queensland state's Lockyer Valley on Monday, state Premier Anna Bligh said.
The valley funneled rain from a freak storm — forecasters estimated up to 6 inches (150 millimeters) fell in half an hour fell 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 toward the state capital of Brisbane, Australia's third-largest city with some 2 million people.
The Brisbane River overflowed its banks Tuesday and officials warned that dozens of low-lying neighborhoods and parts of the downtown area could be inundated by Thursday.
The violent surge near Toowoomba on Monday escalated Australia's flood crisis in Queensland state and brought the overall death toll to 19. 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 in the path of the floodwaters, Forest Hill, the entire population of about 300 was being airlifted to safety in military helicopters, Bligh said.
The search and rescue effort was being hampered by thunderstorms and more driving rain.
Brisbane Mayor Campbell Newman said authorities were preparing for about 6,500 properties to be flooded in the city in the next few days, affecting about 15,000 people in 80 suburbs. The flood peak was expected on Thursday, when parts of downtown were expected to be awash.
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 in the city, Newman said. The alternative was a much worse torrent.
Bligh said four children were among those killed and that many of those still stranded or unaccounted for are families and young children. On Tuesday morning, she said the death toll was eight and the missing numbered 72. Later, she confirmed another death and said five of the missing had been accounted for.
Queensland has been in the grip of its worst flooding for more than two weeks, after tropical downpours across a vast area of the state covered an area the size of France and Germany combined. Entire towns have been swamped, more than 200,000 people affected, and coal and farming industries virtually shut down.
"The power of nature can still be a truly frightening power and we've seen that on display in this country," Prime Minister Julia Gillard said.
Monday's flash flooding struck without warning in Toowoomba, a city of some 90,000 people nestled in mountains 2,300 feet (700 meters) above sea level. Bligh said an intense deluge fell over a concentrated area, sending a 26-foot (eight-meter), fast-moving torrent crashing through Toowoomba and smaller towns further down the valley.
Police Commissioner Bob Atkinson described the events Monday as "an inland instant tsunami."
As the water was pushed its way downstream, officials closed roads and highways and told residents in low-lying area of Brisbane to sandbag their homes and then move to higher ground.
"We have a grim and desperate situation," Bligh said. "This took everybody so unawares that there was no opportunity in most cases for people to get to safety."
Heavy rain continued Tuesday, and the Bureau of Meteorology warned that more flash floods could occur.
Deputy Police Commissioner Ian Stewart said rescue efforts were concentrated on towns between Toowoomba and Brisbane, including hardest-hit Murphy's Creek and Grantham, where about 30 people sought shelter in a school isolated by the floodwaters.
News video from late Monday showed houses submerged to the roof line in raging muddy waters, with people clambering on top. A man, woman and child sat on the roof of their car as waters churned around them.
In Toowoomba, the waters disappeared almost as fast as they arrived, leaving debris strewn throughout downtown and cars piled atop one another.
Queensland officials have said the ultimate cost of the weekslong flooding could be as high as $5 billion.