Two Cyclones Roar Towards Australia

Two cyclones were roaring towards Australia on Thursday with residents scrambling for shelter as one of the tempests rapidly picked up intensity, with warnings of "a very destructive core".

Tropical Cyclone Lam, a category three storm, was tracking towards the sparsely populated Northern Territory Aboriginal communities of Milingimbi and Gapuwiyak, with landfall expected early Friday morning.

Of more concern was Tropical Cyclone Marcia further south, which was reclassified from a category two to four within hours and a warning that it could strengthen to five by the time it comes ashore in heavily populated southeast Queensland.

"Severe tropical cyclone Marcia has become slow moving and continues to intensify, category 5 forecast for landfall," the Queensland Bureau of Meteorology tweeted, with the storm expected to power across the coast on Friday morning.

Cyclones, which are common in northeastern Australia, range from one to five in strength, with five the most severe, capable of causing structural damage, uprooting trees and overturning caravans and trailers.

Massive seas, a deluge of rain, flash flooding and gales force winds of up to 270 kilometres per hour (165 miles per hour) are forecast along with abnormally high tides when it hits somewhere between the towns of Mackay and Gladstone.

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).

"This is a serious event. It has changed drastically since this morning," said Queensland Premier Annastacia Palaszczuk.

"Queenslanders need to be prepared now. This is an important time now not to panic but to make sure you have your preparations in place."

Towns near the eye of the storm were in lockdown and cyclone centres set up in Mackay, Proserpine and Yeppoon, some 670 kilometres (415 miles) north of Brisbane.

Palaszczuk said all Queensland hospitals had activated their emergency plans and additional ambulance services had been moved to some areas. In Yeppoon, supermarket shelves were emptied and sandbags filled as locals readied for a long night.

"It's the unknown that's the worry," Deeann Busby told the Brisbane Courier Mail newspaper as she taped up windows in her homewares shop and cafe.

"We've had so many close calls over the years that we've probably gotten a bit complacent -- but this one's looking a bit more serious."

Further north, more than 400 residents of Goulburn Island, one of the most remote places in Australia, were moved to safety in the regional centre of Darwin as Cyclone Lam continues its approach.

In another community on the storm's path, Galiwinku, local teacher Josh Keating said power and water supply had already been cut off. "Trees have started to go down. It is starting to get a bit hairy," he told reporters.

"Power and water is a concern, as we don't know how long it will be before we get it back. It could be a matter of days, or it could be a week."