Flood warnings issued after tropical cyclone hits northwest Australia

Tropical cyclone Zelia crossed the coast of Western Australia (WA) near the small town of De Grey in the state's northwest Pilbara region as a category four storm shortly after midday local time on Friday, hours earlier than expected. It was forecast to reach the coast in the evening as a category five storm.

Wind gusts of up to 220 km per hour and over 500 millimetres of rain were recorded in De Grey before the storm quickly weakened.

Authorities on Saturday morning downgraded it to an ex-tropical cyclone but warned that heavy rain is expected to persist and could lead to flash flooding.

Angus Hines from the Bureau of Meteorology (BoM) said that record rainfall has been reported across parts of the Pilbara coast.

"There will be significant flooding impacts for the next several days and widespread road closures are expected to continue for the next several days as the clean-up continues," he told the Australian Broadcasting Corporation.

The strong winds downed trees across the region but as of Saturday morning no major damage or injuries had been reported. A flood watch has been issued for Fortescue River, Onslow Coast, Ashburton River, Gascoyne River, and parts of the Sandy Desert catchment.

Some towns have been isolated after roads were cut off, Xinhua news agency reported.

Hines said that significant road closures should be expected as water levels rise.

The WA Department of Fire and Emergency Services has urged Pilbara residents to exercise caution around damaged buildings, floodwaters and fallen powerlines and trees.

Additional emergency services have also begun to arrive at the Port Hedland Airport with commercial flights expected to resume on Sunday.