Twin cyclones force largest evacuation since Cyclone Tracey in 1974

Twin cyclones approaching Western Australia and the Northern Territory have forced the largest evacuation since Cyclone Tracey in 1974 with remaining residents advised to seek shelter.

Air evacuations have now been suspended in the NT before Cyclone Trevor’s crossing as a category four system.

Chief minister Michael Gunner this week announced a state of emergency as the top end embarked on its largest pre-cyclone evacuation in the territory’s history.

Three Royal Australian Air Force C-130 Hercules aircraft on Wednesday and Thursday were evacuating people from Groote Eylandt and McArthur River Mine near Borroloola. Tents were set up at sites in Darwin and Katherine for evacuees and public cyclone shelters prepared.

Related: Cyclone Trevor could reach category 4 as it crosses Northern Territory coast

Overnight, authorities suspended Groote Eylandt airlifts because the cyclone’s path had changed, regional commander Travis Wurst said. Nhulunbuy residents are also no longer required to evacuate.

“Groote Eylandt is expected to feel some effects of the cyclone including destructive winds, heavy rainfall and abnormally high tides,” the Northern Territory government said in a statement.

“All other evacuations have now ceased due to the weather being experienced in the affected areas.”

The last family has been evacuated from the tiny Northern Territory town of Borroloola.

Speaking from her family’s car as they sped inland away from the approaching storm, Christine Sauer said only the local police and utilities workers remain in the community of about 900 people.

Related: Cyclone Trevor hits the Queensland coast with 200km/h winds

Sauer and her family, who run the town’s local shop and service station, plan to sit out the storm at a friend’s cattle station about 170km away.

“We hope we’re safe but it’s not the first cyclone we’ve seen in our 25 years here,” she said.

The NT government is warning residents to monitor emergency alerts. “Prepare your emergency kits, finalise your plans and know where the public shelter is if you need to move there.”

Trevor left behind a trail of damage in Queensland’s Cape York peninsula earlier this week, uprooting trees, causing flooding and roof damage, closing schools and roads, and knocking out power supplies.

Rainfalls of 150-250 millimetres are predicted on Saturday, with isolated falls to 300mm along the coast.

“As the rainfall extends inland into the Barkly from Sunday, road conditions may be affected in many areas, with some communities potentially becoming isolated,” the NT government said in a statement.

A dangerous storm tide is expected in coastal areas between Groote Eylandt, Burketown and the NT-Queensland Border from Friday afternoon.

Gales with gusts to 120 kilometres per hour are expected to develop on Groote Eylandt and Mornington and Sweers Islands from Friday afternoon and extend to the mainland coast between Cape Shield to Karumba that night.

The gales will move into the eastern Carpentaria and northern Barkly districts and north-west Gulf country on Saturday morning.

Inland locations likely to be affected by wild winds and rain include Doomadgee, Creswell Downs, Cape Crawford, Robinson River and Wollogorang.

In Western Australia, cyclone Veronica is set to intensify to a category five system. But it is expected to cross the Pilbara coast at category four level.

At a Woolworths supermarket in Port Headland, frantic shoppers have stripped the shelves bare of bottled water and were bulk-buying cans of food and long life milk.

“We’re waiting for a truck to bring in more water bottle supplies this afternoon,” a staff member told Guardian Australia.

The Bureau of Meteorology says the Pilbara region may be severely affected over the weekend.

“While it is possible the cyclone may weaken before reaching the Pilbara coast, a severe impact is likely,” the bureau said.

Gales with gusts to 100 kilometres per hour may develop between Pardoo and Mardie on Friday evening, and may extend further east to Wallal and adjacent inland areas later on Saturday.

Destructive winds with gusts exceeding 125km/h are forecast to develop along the coast between Dampier and Pardoo later on Saturday.

The bureau predicts very destructive winds with gusts in excess of 165 kilometres per hour as the cyclone centre approaches the coast over the weekend.

With additional reporting from Australian Associated Press.