The slow-moving cyclone, which is currently a category two, spent much of the day stationary but is now only 250 kilometres north of Port Hedland and 345 kilometres west of Broome.

Areas of the Pilbara and Kimberley coastlines have already been put on yellow alert for the cyclone, which was moving south on Monday night.

The Bureau of Meteorology say the storm front could be as intense as a category four as it crosses the coastline later this week, which could bring wind gusts as high as 230km/h.

WA's State Emergency Service (SES) is advising people in communities between Broome and Mardie, including Port Hedland and Karratha, to prepare an emergency kit including first aid provisions, a torch, a portable radio, spare batteries, food and water.

Brent Rudler, who is running a bottle shop in Port Hedland said residents were already taking the latter portions of that advice very seriously.

"You can't buy a bottle of water in town for any money," Mr Rudler told Radio 6PR.

"I've told my staff today there is 400 millimetres of it coming, so they should just stick a bucket outside."

Mr Rudler said people in Port Hedland were wary of Rusty, which is looming as the biggest cyclone of the season so far.

"The road headed south is very busy. Nobody wants to go north," he said.

"There are guys I have known for 20 years who have packed up and flown out because they say they have have a funny feeling about this one."

The yellow alert, which indicates a possible threat to lives and homes, extends from the coastal communities of Wallal to Whim Creek in the Kimberley, to Pardoo, De Grey and Port Hedland in the Pilbara.On Tuesday afternoon, gales could extend west to Karratha and begin to move inland towards Marble Bar and Millstream.

More than 830mm of rain has been dumped on the Cocos Islands in the past three days - eclipsing the amount that fell in metropolitan Perth in 2012 by more than 200mm.

Bureau spokesman Neil Bennett said Rusty's intensity, size and slow movement was also likely to lead to a dangerous storm tide, including damaging waves.

Mining giant Rio Tinto said it had prepared for the storm by closing the Port Walcott port at Cape Lambert and was finishing up ship-loading at its Dampier ports.

The Port Headland Port Authority said it had evacuated the port on Sunday night and would stay closed.

Virgin cancelled flights from Perth to Broome on Monday, and local businesses reported people were dashing to buy water and tinned food as the storm approached.

Port Hedland and Dampier ports were being closed and all vessels sent out to sea on Monday in preparation for Rusty's arrival.

"We expect to be fully closed by this evening", Port Hedland Harbour Master John Finch said on Sunday.

Cyclone Rusty threatens to bring mining and oil and gas production to a standstill.

The area holds shipping terminals at Port Hedland, where BHP Billiton, Fortescue Metals and Atlas Iron are forecast to ship more than 275 million tonnes of iron ore this year.

The ports of Dampier and Cape Lambert, about 200 kilometres south of Port Hedland are used by Australia's biggest iron ore miner Rio Tinto.

The region is also home to two of the country's largest gas production facilities, Woodside's Northwest Shelf and Pluto liquefied natural gas plants.

A total of 11 schools have already been closed because of the cyclone threat.

Rainfall

Rusty's slow motion should also result in higher than usual rainfall in the Pilbara and western Kimberley and very heavy falls expected near the coastal parts of the eastern Pilbara and western Kimberley on Monday.

During Tuesday and Wednesday widespread heavy rainfall is likely to lead to major flooding in the De Grey catchment. Significant flooding in the Fortescue is also likely.

For more information visit the DFES website.