A tropical storm to the north Western Australia It is expected to become a severe category three system.
Cyclone Michelle is offshore Port Hedland and moving southwest towards the Karratha coast in the early hours of Saturday morning.
Officials expect the storm to continue southwesterly and cross the western Pilbara coast on Sunday afternoon.
It will intensify into a category three system as it moves north of Karratha on Saturday night and nears the Pilbara coast on Sunday.
According to the Bureau of Meteorology, the most damaging wind gusts could reach 170km/h in Karratha, Dampier and Wickham and Anns further south on Saturday night.
A WATCH and ACT warning is in effect from Wim Creek to Mardy, including Borough Island and Montebello Island, with residents told to prepare to evacuate as lives and homes are threatened.
Residents east of Pardue Roadhouse to Wim Creek, and south of Mardy to Carnarvon and Pannavonica are advised to monitor conditions and prepare for hazardous weather.
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An evacuation center was opened at the Karratha Leisureplex from Saturday afternoon, with people advised to bring essential items such as medicine and identification, but not pets.
Ports of Ashburton, Cape Preston West, Dampier, Port Hedland and Varanus Island were closed as the weather system approached.
Up to 130mm of rain is expected in Port Hedland on Saturday, bringing with it the risk of flash flooding.
Officials have warned the central and western Pilbara coast will face the risk of flooding over the weekend, with the western Gascoyne region also likely to be affected by Monday.
Abnormally high tides will also pose a severe flood risk for the Karratha area early Sunday morning and Ans until Sunday afternoon, the bureau said.
Before the storm hit as other outback towns were still feeling the brunt of major flooding.
In the Northern Territory, more than 400 people who took a 230km bus ride from Daly River to Darwin on Wednesday will have to wait days to return as river flooding is expected to peak early next week.
Incident Controller Supt David Moore said 298 evacuees, including 110 children, were housed in the Foskey Pavilion at the Darwin Showgrounds.
