“Tides are likely to rise significantly above the normal high tide mark with damaging waves and dangerous flooding of some low-lying areas close to the shoreline,” it said in an update.
The cyclone was forecast to land near Port Hedland – about 17 hours' drive north of state capital Perth – before tracking inland across sparsely populated mining and cattle country.
Initially arriving as a category five cyclone, Zelia was expected to weaken to a category four later in the evening.
Pilbara Ports said it had cleared vessels and shut down operations at major minerals export centres Port Hedland and Port Dampier as well as the oil and gas shipping port of Varanus Island.
Emergency services in Western Australia told people still in the cyclone’s path to shelter in the strongest part of their homes, warning it was now too late to attempt to leave.
The northwest coast of Western Australia is the most cyclone-prone region in the country, according to the Bureau of Meteorology.
It also has “the highest incidence of cyclones in the southern hemisphere”.
The region holds significant deposits of iron ore, copper and gold, and is home to some of Australia’s largest mining operations.
Mining group Rio Tinto said its ships and trains had been cleared from ports in the area.
“It is too early to say how long port and rail operations will be closed and what the impact will be,” it said in a statement Thursday.
-Agence France-Presse