Australia warns of 'calamity' as massive cyclone roars ashore

A powerful cyclone roared ashore in a heavily-populated area of Australia Friday with authorities warning of a "calamity" and residents told to expect "a harrowing and terrifying experience".

Tropical Cyclone Marcia slammed into the Queensland coast just after 2200 GMT Thursday and is expected to cause significant damage after being upgraded to a category five, the most severe.

"Severe Tropical Cyclone Marcia, category 5, is currently moving onto the Capricorn coast near Shoalwater Bay, north of Yeppoon," the Australian Bureau of Meteorology said.

Yeppoon, home to around 16,000 people, is some 670 kilometres (415 miles) north of Brisbane.

"It is expected to continue moving in a southerly direction over land close to the coast during today," the bureau added.

Massive seas, a deluge of rain, flash flooding and wind gusts of up to 295 kilometres per hour (182 mph) were expected along with abnormally high tides.

"The wind is starting to really pick up," Katrina McDonald, who lives just outside Yeppoon, told the Brisbane Courier Mail newspaper as the storm hit.

"The creek that runs through our property is roaring."

Resort operator Sian Appleton said Great Keppel Island off Yeppoon was preparing for serious damage.

"We've lost a lot of sand, erosion has been fairly heavy," she told national broadcaster ABC.

"I think we'll probably lose three cabins and maybe even some of the bistro area."

Queensland Police Commissioner Ian Stewart said it was a "desperate situation".

"This is going to be a calamity, no doubt about that," he said ahead of the tempest making landfall.

"Our primary focus from this point on is the safety of all human life in that area."

Two fishermen who were missing have since been found and no other major incidents have been reported so far, Stewart added, while urging people to stay indoors.

The Australian Bureau of Meteorology's senior forecaster Sam Campbell said significant damage was expected.

"This is an extremely dangerous system," he said.

"There's likely to be significant damage to roofs, buildings, debris flying through the air, widespread power failures and really the potential for widespread destruction over the warning area."

Standing by your side

Queensland Premier Annastacia Palaszczuk said the full brunt of the storm would be felt around the Yeppoon area before it eases to a category three as it travels south.

More than 60 schools have been closed and businesses shuttered. As far away as Brisbane, residents were urged to start sandbagging and clear their yards of any objects that could be whipped away by the wind.

"Over the next few hours, many thousands of Queenslanders are about to go through a harrowing and terrifying experience and I want those people to know that we are with you every step of the way," said Palaszczuk.

"We will be standing by your side. This a severe cyclone. I want everyone to take all the precautions that they possibly can take."

She added that all Queensland hospitals had activated emergency plans and additional ambulance services had been moved to some areas.

Queensland has been smashed by several major storms and cyclones over the past few years with Cyclone Oswald, also a category five, flooding parts of the state in 2013, racking up insurance claims of some Aus$977 million (US$765 million).

In a rare occurrence, a second big storm -- Tropical Cyclone Lam -- crossed the coast further north just hours earlier after intensifying to a category four overnight.

That area, around the Northern Territory Aboriginal communities of Milingimbi and Gapuwiyak, is far less populated.

Meteorologists described both storms as having a "very destructive" core.

Police said the remoteness of the region meant authorities were not yet able assess damage in the area.

Five facts about tropical cyclones in Australia as two powerful systems hit areas in the northeast on Friday:

* Cyclones are low pressure systems that form over warm tropical waters, with gale force winds near the centre. The winds can extend hundreds of kilometres (miles) from the eye of the storm.

* They are also known as hurricanes or typhoons, depending on where they originate in the world, when they reach sustained winds of 119 kilometres per hour (74 mph) or higher. Tropical cyclones are common in Australia's northeast and northwest during the warmer months, with the season running from November to April.

* Australia uses a different scale to the rest of the world when rating the intensity of cyclones. They are categorised from one to five, with five the worst. A category five has gusts of more than 280 kilometres per hour (173 mph) and is extremely dangerous with widespread destruction.

* A five also produces heavy rainfall with flash flooding and massive seas. Storm surges when the cyclones reach land raise domes of water of about 60-80 kilometres (37-50 miles) across and about two to five metres higher than the normal tide level.

* Category fives Oswald in 2013 and Yasi in 2011 caused serious flooding damage in parts of Queensland and raked up billions of dollars in insurance claims. The worst cyclone in Australia was Tracy, which hit Darwin on Christmas Day in 1974, killing 65 people and flattening more than 90 percent of the northern city's homes.