THE largest evacuation before a cyclone in the Northern Territory's history is underway with Cyclone Trevor due to make landfall on Saturday.
Cyclone Trevor is expected to make landfall along the Carpentaria or east Arnhem coastlines Saturday as a Category 4 storm, classified as "severe" by the Bureau of Meteorology with wind speeds up to 170 miles per hour.
Residents of Groote Eylandt and Numbulwar are being told to evacuate, and other communities are being told to prepare to evacuate.
Australia's Bureau of Meteorology said Cyclone Trevor, with sustained winds of 125 miles per hour (200 kph) and gusts up to 160 mph, was expected to bring heavy rainfall and a risky storm surge.
Trevor's wind strength was the equivalent of a Category 2 hurricane at first landfall.
Evacuations are now mandatory after the state of emergency was declared.
"The waters right through the Gulf of Carpentaria are going to be risky from Thursday, with gale-force winds and rough seas developing early on Thursday as the system re-intensifies", the Bureau of Meteorology's NT manager, Todd Smith, told the ABC.
Ergon Energy's spokesperson Emma Oliveri has confirmed their crews are working in the north of Queensland after more than 400 homes lost power when Trevor crossed the state's coast.
Australian Defence Force Hercules' aircraft are being used to transport people, who have begun arriving in Darwin and Katherine where indoor sleeping facilities are being set up at local showgrounds.
About 600 out of Groote Eyland's population of 2800 have been evacuated but authorities are now focusing on Borroloola, with a population of 900. Most would be housed in temporary accommodations in Darwin, he said. Steps were being taken to ensure indigenous cultural protocols were respected and tribal languages used.
With Tropical Cyclone Trevor (TC Trevor) continuing to batter cape communities' police would like to remind members of the community to exercise extreme caution with damaging winds, heavy rainfall, possible flash flooding and hazardous surfs being experienced across Far North Queensland.
Meanwhile, Cyclone Veronica has grown from a Category 1 to a "sever Category 4 system" with winds of 155 mph in the last 24 hours and is expected to make landfall over the weekend, Bureau of Meteorology Meteorologist Andrea Peace said.