Severe Tropical Cyclone Zelia strengthened to category 5 strength on Friday and will strike the WA coast about 1600km north of Perth on Saturday.

Gusts of up to 290km/h and more than 500mm of rain are forecast across the Pilbara coast from tonight into tomorrow.  

The Bureau of Meteorology warns Zelia, which reached category 4 overnight, is rapidly intensifying.

The Australian Reinsurance Pool Corporation says it is a declared cyclone event, with the beginning of the claims period set at 4am AEST yesterday.

Bureau senior meteorologist Angus Hines said this afternoon the centre of the cyclone was about 120km north-northwest of Port Hedland and was moving slowly, about 5-10km/h, to the southwest.

“It’s an organised and powerful tropical cyclone that will play a significant role in the weather across this part of the country in the next few days,” he said.

“Category 5, that is the top of the scale. It doesn’t get any worse than that ... it is forecast to be a category 5 system as it approaches and crosses the coast on Friday.”  

Zelia is expected to cross tomorrow at 5pm-6pm AWST near Karratha, which the bureau says may “see some more significant and severe impacts than what had been expected over the last couple of days”.

Winds of 80-120km/h are forecast, and near the crossing point they could be as high as 200km/h with gusts up to 290km/h.

“That is strong enough to take out ... houses, trees, power lines and cause widespread damage and disruption. Along with those destructive winds, we anticipate some significant rainfall,” Mr Hines said. 

A cyclone watch and act alert is in place for residents of Port Hedland, Karratha, Dampier and inland to Marble Bar, with communities between Karratha and Bidyadanga near Broome warned of dangerous storm tides.

Schools and the iron ore port have closed, and an evacuation centre will be set up.  

Some areas may have tides about a metre above normal levels. “That can inundate low-lying coastal roads and properties, and cause significant flooding across waterfront and coastal areas, as well as around the ports and boats,” Mr Hines said.  

Rainfall in the Pilbara is expected to continue for many hours with widespread flash and riverine flooding likely.  

Cyclone Sean reached category 4 intensity last month, bringing record rainfall to Karratha and disrupting iron ore shipments while remaining offshore.