Communities along Western Australia's Pilbara coast are bunkering down as they await the arrival of Tropical Cyclone Rusty.

Towns and surrounding areas are on yellow alert for Rusty, which is currently a category three system located about 200 kilometres off the coast and moving south-east at 8kph.

It is moving slowly but at this stage is predicted to become a severe tropical cyclone and make landfall near Port Hedland on Wednesday evening.

The Bureau of Meteorology says gale-force winds are expected on the coast between Wallal and Whim Creek this morning, before extending west to Karratha and inland towards Marble Bar.

During today and tomorrow, widespread heavy rainfall is expected to lead to major flooding in the De Grey and Fortescue catchments and in Pilbara coastal streams.

Tides are likely to rise well above the normal high tide mark, bringing damaging waves and coastal inundation.

The local port has been shut down and about 20 ships are anchored at sea to ride out the storm.