Queensland braced for 'deadliest' storm Cyclone Yasi
Australian officials have warned that Cyclone Yasi, which is approaching Queensland, is likely to be the most deadly storm in living memory.
State Premier Anna Bligh said the storm would be "catastrophic" and that the state was facing "a frightening time".
Yasi has been upgraded to a category five storm - the most severe level.
The army is evacuating hospitals in the northern city of Cairns while residents in coastal areas are being urged to move to safer locations.
Last month the state was severely hit by widespread deadly flooding.
The Bureau of Meteorology (BoM) warned that Cyclone Yasi posed and "extremely serious threat to life and property within the warning area, especially between Cairns and Townsville.
"This impact is likely to be be more life threatening that any experienced during recent generations," it warned.
Yasi, currently 555km (344 miles) east of Cairns and 560km northeast of Townsville, is forecast to make landfall late on Wednesday night local time (after 1200 GMT).
At its centre, the storm has winds of up to 295 km/h (183 mph).
"We are facing a storm of catastrophic proportions in a highly populated area," Ms Bligh told reporters.
"What it all adds up to is a very frightening time. We're looking at 24 hours of quite terrifying winds, torrential rain, likely loss of electricity and mobile phones.
"People really need to be preparing them mentally if nothing else."
Senior BoM forecaster Gordon Banks said the storm had the potential to get even stronger after making landfall.
"As a strong category five we could see wind gusts in excess of 320 kilometres an hour, which is just horrific," Australia's ABC News quoted him as saying.
"If you're bunkering down in the regions, it's going to be quite frightening and it's going to go on and on for quite some time."
Cairns airport was scheduled to close on Wednesday. Rail lines, mines and coal ports have already shut down.
In Townsville people were reported to be crowding around the airport. One resident, Tracy Gibbons, told Reuters that there was panic buying.
"It's crazy in the shops. People are nearly killing themselves to get food and water before this thing hits," she said.
The storm has changed course in the last 24 hours and now appears set to spare central and southern parts of the state devastated by recent flooding.
It now looks likely to hit the Cairns area, but forecasters say its effects may be felt hundreds of kilometres away.
Airlines have put on extra flights to northern Queensland to help evacuate residents and tourists, while holidaymakers have been leaving resort islands.
About 250 patients from two hospitals in Cairns are being flown by the air force to Brisbane, because of expected flooding from the storm surge.
Queensland Deputy Police Commissioner Ian Stewart urged residents in affected areas to evacuate their homes on Tuesday and head south to safer regions.
"At about 0800 tomorrow, on current predictions, it will become dangerous to be driving about or walking about or doing anything outside due to the force of the winds," he said.
Officials say mandatory evacuations are likely to be enforced in Cairns. Some forecasters have predicted up to three feet of rain could fall on some coastal communities.
Yasi is expected to be more powerful than Cyclone Larry, which slammed into Queensland in March 2006, leaving thousands of people homeless.