The world’s largest iron ore export center, Australia’s northwest region, was preparing on Thursday for the area’s most violent tropical storm in a decade, as a key port shuttered and locals scrambled to stock up on crucial supplies.

Cyclone Ilsa, which is around 250 kilometers (155 miles) off the coast of Australia in the Indian Ocean, was upgraded to a category four storm on Thursday morning.

The Bureau of Meteorology predicted it will reach category five before reaching landfall late Thursday or early Friday with gusts of up to 285 km/h (177 mph).

“They’ve got a lot of strength in them, the ability to not only destroy trees and knock down power lines but lift up those loose items in the yard, including trailers and caravans,” meteorologist Miriam Bradbury told ABC television.

The weather bureau said in its latest update that Ilsa could impact a 600 km sparsely populated stretch from just north of Port Hedland eastwards to just south of tourist town Broome.

Port Hedland’s port, the world’s biggest iron ore export point, closed on Thursday morning after the port authority began clearing berths a day earlier.

The port is used by BHP Group, Fortescue and billionaire Gina Rinehart’s Hancock Prospecting. Rio Tinto exports out of the Port of Dampier, to the west of Port Hedland.

The weather bureau said Port Hedland may be spared by “the very destructive core of Ilsa” but winds with gusts of up to 155 km per hour could still lash the mining town.

It will be the strongest system to hit the country’s far northwest region since Cyclone Christine crossed the coast in December 2013, weather bureau forecaster Jessica Lingard said.