Tropical Cyclone Ilsa has been officially declared, and is expected to intensify rapidly on its way to becoming north-west Western Australia’s most significant storm in a decade.

Evacuations are under way across the region as tourists, miners and pastoralists flee the strengthening cyclone’s projected path.

Tropical Cyclone Ilsa was officially declared by the Bureau of Meteorology on Wednesday morning. It is expected to become the first category-four system to strike the region in more than 10 years when it hits the coast between Broome and Port Hedland.

By early Wednesday afternoon, Ilsa was about 400 kilometres north-north-west of Broome and 700 kilometres north-north-west of Port Hedland, moving south-west at 13 km/h.

“Cyclone Isla is expected to intensify further during Tuesday and Wednesday as it moves south-west, parallel to the Kimberley coast,” the weather bureau said.

“There’s a significant risk it will become a severe tropical cyclone on Wednesday.

“It is expected to track to the south and then south-east during Thursday, with a severe impact likely along the coast and adjacent inland areas between Port Hedland and Broome during late Thursday or early Friday.”

Ilsa is expected to bring heavy rainfall and destructive winds to the western Kimberley region, with storms possibly extending into the Pilbara and northern interior.

Western Australia’s Department of Fire and Emergency Services Commissioner Darren Klemm said remote Aboriginal communities, pastoral stations, mines and tourism operators in the cyclone’s path had been contacted.

Workers at Wallal Downs cattle station, Newcrest’s Telfer mine and caravan parks are being evacuated, along with non-critical workers at BHP’s sites across the region.

People living in structures that are not built to withstand a category-four weather event have been told to move out of the area.

“It’s been 10 years since we’ve had a category-four cyclone impact the coast of WA and so many people up in the Pilbara and the Kimberley wouldn’t have experienced that sort of impact,” Mr Klemm said.

Extra emergency workers, essential supplies and aircraft have also been sent to the region.

Mr Klemm said the North West Coastal Highway between Port Hedland and Broome would likely close in coming days due to flooding.

The Port Hedland port will be cleared of vessels, including iron ore carriers, on Wednesday.

“People need to make sure they’re well prepared for winds in excess of 200km/h, which is going to be significant,” Mr Klemm said.

Bureau of Meteorology spokesman Todd Smith said the cyclone would rapidly grow in strength in coming days and its effects would be felt across a wide area between Broome and Port Hedland.

“It’s going to cause a lot of damage to trees, vegetation and any buildings and infrastructure that aren’t up to code, and caravans, cars are going to get blown around,” he said.

Mr Smith warned abnormally high tides, large waves and flooding were possible and people should avoid coastal and low-lying areas.

He said the weather system could reach hundreds of kilometres inland and towns in the Pilbara region also needed to prepare.

Communities from Beagle Bay to Whim Creek, including Broome and Port Hedland, have been warned to prepare for damaging winds, heavy rainfall and abnormally high tides.

– with AAP