A cyclone carrying winds of up to 250km/h (155 mph) has battered Australian holiday islands as it moves towards the Queensland coast.
Tens of thousands of people have been evacuated in preparation for Cyclone Debbie, a Category four storm.
Its destructive eye has already hit the Whitsunday islands and is expected to reach the mainland by 12:00 local time (02:00 GMT) on Tuesday.
Authorities said it would be the area's worst storm since Cyclone Yasi in 2011.
Prime Minister Malcolm Turnbull earlier urged residents to "leave home immediately", adding that people should seek shelter "on higher ground".
Australia's Bureau of Meteorology said the storm was still gathering strength, despite slowing its progress during the night.
Emergency stockpiles of food and fuel have been set aside and the army is on standby to deal with the storm's aftermath.
Queensland Premier Annastacia Palaszczuk said the emergency evacuation order was "probably the largest ever" for the northeastern state, and warned people to charge their phones as structural damage and power outages were likely.
View from Townsville - Hywel Griffith, BBC News
What is normally a bustling gateway to the Great Barrier Reef has ground to a halt in preparation. Forecasts suggest Townsville may not be hit directly by the storm's core, but winds have already picked up and no-one is taking chances.
Most businesses have shut up shop - some have sandbags lining the doorway. The few coffee shops that have opened are doing a roaring trade. Lines of police officers and firefighters are getting a heavy dose of caffeine to prepare for the long day and night ahead.
Many tourists seem to have moved on, or cancelled their visit completely - one hotelier told me they had lost thousands of dollars in bookings.
Even if Townsville is spared the worst of Cyclone Debbie, it is already feeling the impact.
"This is going to be a monster of a cyclone," Ms Palaszczuk said, comparing it to Cyclone Yasi, which had devastated towns and flooded evacuation centres.
Thousands of people are believed to have left their homes in Mackay, and many more have evacuated their properties in low-lying areas such as Bowen and Ayr.
Ms Palaszczuk said that shelters had been made available on higher ground for those with nowhere else to go.
Some residents refused to leave despite warnings that Cyclone Debbie's destructive core could be as wide as 62 miles (100km).
More than 2,000 emergency workers are also on standby, but people have been warned crews will only respond when it is safe to do so.
'About your safety'
The Bureau of Meteorology said the cyclone could yet "intensify further" as it moves towards the Queensland coast.
Forecasters had feared the cyclone would coincide with high tide, bringing waves of up to 8m (26ft), but the storm is now predicted to arrive later.
Authorities warned there was still dangerous risk of flooding.
"I am just pleading to everyone, please, listen to authorities," Ms Palaszczuk. "I do, you must as well. This is about your safety, it is about the safety of your family and the safety of your children.''
Police Commissioner Ian Stewart said the weather contributed to the death of a woman in a car crash.
Queensland authorities have closed 102 schools, 81 early childhood education centres and two ports.
All flights have been cancelled at Townsville Airport and Mackay Airport.