Perth could see 10 months of rain in 36 hours

People in WA's Pilbara and Midwest Gascoyne regions have been warned to prepare for flooding due to heavy rains from ex-Tropical Cyclone Joyce.

Emergency WA has issued a warning for minor flooding in catchment areas of the Pilbara Coastal, Fortescue, Ashburton, Gascoyne, Wooramel, Murchison and Greenough rivers over the next few days.

Residents have been warned to relocate livestock and equipment early and prepare emergency kits including canned food and water.

As of late Saturday morning, Joyce was south-southwest of Port Hedland and expected to bring heavy rain over the coming days as it crossed the coast.

Falls of 50-80mm are expected and isolated falls of up to 130mm in areas close to the system's path.

It was initially feared the storm would develop into a category three cyclone and wreak havoc with winds of up to 180km/h but they only reached 100km/h and it peaked as a category one.

It was the region's second cyclone in a fortnight after Tropical Cyclone Hilda hit the Broome area.

The closure of Port Hedland has disrupted shipments of Australia's biggest export iron ore by companies such as BHP and Fortescue.