Thousands of people including tourists were evacuated Monday as northeast Australia braced for a "monster" cyclone packing destructive winds, with warnings of major structural damage and dangerous tidal surges.
Cyclone Debbie has been forming off the coast of Queensland state over recent days, the Bureau of Meteorology said, and is expected to make landfall as a category four storm -- on a scale of five -- after daybreak Tuesday.
Residents, who have been sandbagging and boarding up homes, were told to prepare for the worst weather to pummel the state since Cyclone Yasi in 2011, which ripped houses from their foundations and devastated crops.
"This is probably the largest evacuation we've ever had to do," said Queensland Premier Annastacia Palaszczuk, adding that structural damage and power outages were likely.
"This is going to be a monster of a cyclone."
Some 3,500 people have been evacuated between the towns of Home Hill and Proserpine, around 100 kilometres (62 miles) south of Townsville, a tourist hotspot used to access the Great Barrier Reef.
Another 2,000 in the coastal area of Bowen were also on the move, Palaszczuk said, with cyclone shelters available for those with nowhere else to go.
Up to 25,000 more in low-lying parts of Mackay were urged to head to higher ground amid fears the storm could cause a tidal surge up to 2.5 metres (8.0 feet).
The ferocity of Debbie has been building and it was upgraded to a category four cyclone late Monday before making landfall, expected somewhere between Ayr and Mackay, with a warning that "it may intensify further".
The meteorology bureau forecast pounding rain and wind gusts of up 280 kmh (174 miles) near its centre.
"Storm surge is also a risk factor, and if the cyclone crosses the coast around high tide this will enhance these effects," it said, adding that severe flash flooding was possible.
The cyclone is forecast to hit at around 8am (2200 GMT Monday), with high tide in the area at 9.44am.
More than 100 schools have been closed, along with local ports.
'Our block of dirt'
Palaszczuk pleaded with residents to do as emergency service personnel asked, amid reports some were refusing to leave, an appeal echoed by Prime Minister Malcolm Turnbull.
"If you have received an official evacuation order, you and your family must leave immediately," he said.
But some were adamant they were staying, with Mike Kennedy saying he believed many in the small community of Cungulla planned to remain.
"This is our block of dirt and we're going to defend it from the storm if we can," he told the Australian Broadcasting Corporation.
Queensland Police Commissioner Ian Stewart said the storm already appeared to have claimed the life of a tourist, as many visitors flee areas in the firing line.
"There has been a fatal traffic accident near Proserpine and we believe it is associated with this weather event and it looks like a tourist has lost their life in that traffic accident," he said.
"The message is very, very clear at this stage. It is time to think very logically about your safety and the safety of your family."
The federal government said it was ready to provide immediate assistance in the aftermath, with a disaster relief ship en route from Sydney and navy helicopters and planes on standby.
"We are ready and able to respond to this emergency in support of civilian emergency authorities and the residents of northeastern Queensland once the full impact of Debbie is known," said defence force chief Air Chief Marshal Mark Binskin.