The monster cyclone hurtling toward Australia's north-east coast was upgraded Wednesday to the maximum category five, and the 300,000 people in its path were warned of an impact "more life-threatening than any experienced during recent generations", dpa reported.
More than 30,000 people have fled Queensland's far-north ahead of tropical Cyclone Yasi, forecast to hit before nightfall within a 90- kilometre stretch of coast between Cairns and Innisfail.
Weather bureau forecaster Gordon Banks said Yasi was so immense that it would hold its power as it crossed the coast rather than dissipate immediately when it hit land.
"There's still potential for it to become stronger," Banks said. "As a strong category five, we could see wind gusts in excess of 320 kilometres an hour."
There was worse news for Queenslanders still reeling from January's unprecedented flooding that covered two-thirds of the state: the arrival of Yasi coincides with a high tide.
"So, certainly, we'd expect reasonably widespread inundation in the run-up to that crossing," Banks said, warning that beachside properties could be washed away.
The storm surge could add 2.5 metres to the high-water mark.
Queensland Premier Anna Bligh warned those on the Cairns waterfront to leave of their own free will or wait to be forcibly evacuated.
"I don't want to frighten people, or panic them, but ... we're facing a potentially very deadly event," she said.
Cairns hospitals have been closed and hundreds of patients airlifted to Brisbane in military transport planes. The airport is now shut to commercial flights and roads into the city of 122,000 people will be sealed off as Yasi approaches.
Cairns Mayor Val Schier said those who remained should expected a battering 10 hours either side of Yasi's arrival.
"We want people to try and keep calm but they must be prepared for what's going to be a real battle," she said. "In the end, if people want to stay, they're taking responsibility for their own life."
Tropical cyclones occur regularly on the north-east coast in the southern hemisphere summer. They form in the Pacific when a cluster of thunderstorms combine and their force has been compared with a chimney sucking up energy at its base and shooting it out the top.
Yasi is expected to be the most destructive ever, easily eclipsing category-four Cyclone Larry, which in 2006 tore through the coastal community of Innisfail, rubbishing crops and damaging 10,000 houses.
Yasi is stronger, and twice the size, of Larry. It matches the size and intensity of Hurricane Katrina, which slammed into the southern US city of New Orleans in 2005 causing catastrophic flooding and killing 1,863 people.
...