CAIRNS, Australia (Reuters) - Thousands of residents fled their homes and crammed into shelters in northeastern Australia as a cyclone described as the most powerful in the country's history and with a 650 km (400 mile) wide front barreled toward the coastline on Wednesday.
"We are facing a storm of catastrophic proportions," Queensland state premier Anna Bligh said after Cyclone Yasi was upgraded to a maximum-strength category five storm.
It is expected to hit the coast on Wednesday evening, packing winds in excess of 280 km (175 miles) per hour. The weather bureau predicted it would be the strongest ever to hit Australia, Sky TV reported.
"All aspects of this cyclone are going to be terrifying and potentially very very damaging," Bligh added, noting the greatest threat to life could come from storm surges along the coast with the system due to hit when the tide is high.
Mines, rail lines and coal ports have all shut down, with officials warning the storm could drive inland for hundreds of kilometres, hitting rural and mining areas still struggling to recover after months of devastating floods.
Outside a shuttered night market in the tourist city of Cairns, nervous backpackers tried to flag down cars and reach temporary evacuation centres at a nearby university.
"We are terrified. We have had almost no information and have never seen storms like this," said Marlim Flagar, 20, from Sweden.
At a sprawling shopping centre on the outskirts of Cairns, hundreds of people streamed into a makeshift shelter, carrying backpacks, blankets and food.
"We've bought tinned food and cucumbers. That's all we could find this morning," said Natalie Zerbach, on holiday from Germany.
The cyclone is 650 km off the coast of northeastern Australia and is expected to make landfall at 10 pm (1200 GMT) on the Queensland coast between Cairns and Innisfail. Its strength is on a par with Hurricane Katrina, which devastated New Orleans in 2005.
More than 400,000 people live in the cyclone's expected path, which includes the cities of Cairns, Townsville and Mackay. The entire stretch is popular with tourists and includes Australia's Great Barrier Reef.
The weather was overcast with winds picking up in Cairns early on Wednesday. The main streets were largely deserted. Shops were closed and windows taped to stop shards of flying glass.
At a coffee shop on the Cairns waterfront, Scott Warren covered windows with black plastic sheeting and sandbags from a pickup truck, trying to work out how high he would need to build the barrier to escape a possible storm surge of seawater.
"We get a heap of cyclones every year, but this one has got everyone's attention," Warren said. "We're hoping for the best, but expecting the worst to be honest."
An updated cyclone warning from Queensland disaster officials said: "Severe tropical cyclone Yasi is a large and very powerful tropical cyclone that poses an extremely serious threat to life and property. This impact is likely to be more life threatening than any experienced during recent generations."
On Tuesday the military began evacuating nearly 40,000 people from low-lying coastal areas, with the high winds expected to create a storm surge of 5 metres, which could carry water far inland.
At Cairns airport, people queued from dawn to catch the last flights out of the city before the terminal was locked down and sandbagged against potential storm surges.
"We're so relieved to be on," said Paul Davis, from Sydney, as he stood in the line with his partner Sylvia Leveridge and 3 year-old daughter Ella.
Queensland, which accounts for about a fifth of Australia's economy and 90 percent of steelmaking coal exports worth about $20 billion a year, has had a cruel summer, with floods sweeping the eastern seaboard in recent months, killing 35 people.
Writing by Ed Davies, Editing by Dean Yates