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Brisbane residents are set to wake to scenes of devastation despite the welcome news that the flood peak has been downgraded, Premier Anna Bligh has warned.
In a minor respite, the Brisbane River is now expected to peak at 5.2m, down from the earlier forecast of 5.5m and also below 1974 levels.
While it means the number of affected properties has also been downgraded from 40,000 to 36,000, Ms Bligh maintains that Brisbane faces a huge test.
"It is good news that peak has been revised down slightly," she told Network Ten on Wednesday.
"But this is still a major event, the city is much bigger, much more populated and has many parts under flood that didn't even exist in 1974.
"We are still looking at an event which will cripple parts of our city."
Rising floodwaters have now inundated 35 suburbs in Brisbane, prompting mass evacuations and chaos in the CBD as roads were cut and power and other essential services were shut down.
Hundreds of Brisbane residents have been forced to relocate to evacuation centres, with authorities predicting the figure to rise dramatically and have boosted capacity from 6,500 to 16,000.
Some 14,600 homes and 2,800 businesses are predicted to be completely flooded by the end of the event, possibly mimicking scenes in St Lucia and New Farm, where whole streets were submerged.
"Brisbane will go to sleep tonight and wake up to scenes that they have, many of them, never seen anything like in their lives," Ms Bligh told reporters late on Wednesday.
Drama revisited the 20 evacuees who had taken shelter at the Yeronga State School after it lost power.
They had to be relocated to the temporary digs at QE II stadium.
The CBD has been left a "ghost town" according to Ms Bligh, with shops, offices and buildings closed, 106 roads blocked and public transport running on limited services.
It is predicted 1,657 roads will end up either partially or completely flooded.
Energex began shutting down power in parts of the CBD early on Wednesday morning as a safety precaution, while thousands more residences around the city were also without electricity.
A Tennyson bulk substation was hit with water late on Wednesday, resulting in a temporary outage affecting more than 50,000 in Brisbane's inner-west.
Late on Wednesday 155,000 Queenslanders were without power.
Debris in the raging Brisbane River has captured the attention of emergency crews, who will work into the night to secure at least three large objects that are threatening to come loose.
An anchor will be helicoptered in to secure the Moggill Ferry, while a special team of navy divers are being flown in from Sydney to work out what to do with the Island party boat.
Officials will also work through the night breaking apart the popular floating walkway near New Farm, which will then be disposed of.
Hundreds lined Kangaroo Point throughout the day to take photos and point out boats, pontoons, even a riverside restaurant - the now-appropriately named Drift Cafe - which became floating hazards.
Brisbane hospitals have ceased all non-urgent surgery, although emergency departments are still being staffed.
No one has been spared in the disaster, with garbage collections suspended for a week, phone lines affected and Australia Post warning of significant delays across the state.
There were also fears that the water supply will run out or be contaminated, but Ms Bligh was confident that the southeast corner of the state will get all the drinking water it needs.
The state government issued an urgent warning to residents, telling them to beware of solar panels that might have become live because of the floodwaters.
Brisbane City Council believes it may take up to 12 hours for the waters to recede.