Tropical Cyclone Lam has strengthened to a category four system as it passes near to Elcho Island where several thousand people are sheltering without power.
Winds are gusting at 230 km/h as the system moves towards the Northern Territory mainland.
Earlier on Thursday, 430 people from the Aboriginal community of Warruwi on Goulburn Island were evacuated to Darwin on helicopters and planes.
Eighteen small planes and two helicopters have been shuttling between Warruwi and Darwin, about 300km southwest, and by early afternoon on Thursday about half the people had arrived at the emergency shelter at the Darwin Showgrounds.
The Bureau of Meteorology (BoM) has advised it expects the cyclone will cross the NT’s mainland coast between Milingimbi and Gapuwiyak early on Friday morning.
Forecaster Ben Suter said Elcho Island was currently bearing the brunt of the cyclone.
“Residents should be bunkered down in safe housing at the moment.” he said.
“The next concern is, as the cyclone moves closer to land on the south-west trajectory and then mainland, locations and communities between Milingimbi and Elcho Island will be next in line as we move into the overnight period.”
This comes as Tropical Cyclone Marcia is threatening Queensland’s coast, which is expected to make landfall at a destructive category five system, early Friday morning.
Up to 5,000 people in remote Arnhem Land Indigenous communities have so far been directly affected by the cyclone, authorities have said.
NT Chief Minister Adam Giles said the evacuation from Warruwi was proceeding well and necessary to ensure the safety of residents.
“At this stage it is a very well structured risk-management process,” he said.
Residents urged to take shelter
Remote communities are predicted to be hardest hit, with Cyclone Lam set to make landfall at Nhulunbuy and Elcho Island in Arnhem Land, 1000km from Darwin.
Residents have been advised to take shelter immediately, with flood warnings in place for coastal areas.
Late Thursday afternoon Elcho Island had lost power and water supply as strong winds herald the arrival of the cyclone.
NT residents in older community housing have been encouraged to relocate to shelters at the local school and Marthakal Aboriginal Corporation workshop.
Both are housing approximately 400 people and are being manned by local teachers and volunteers.
Northern Territory police said arrangements were in place to evacuate the 350 people living on Goulburn Island to Darwin.
Meanwhile, there are additional concerns for the nearby communities of Gapuwiyak and Milingimbi.
A storm surge is predicted to coincide with a very high tide on Friday morning, which could create serious flood damage for these low-lying communities.
Social media users have already begun sharing photos from inside storm shelters.
— David Wyllie (@journodave) February 19, 2015
– with ABC