Twin "very destructive" category 4 cyclones were bearing down on Australia's northern and western coasts on Saturday, forcing evacuations in both regions, officials said.
Cyclone Trevor, pushing a huge storm tide and packing winds of up to 250 kilometres per hour (150 mph), was expected to make landfall Saturday on the sparsely populated Northern Territory coast near the Gulf of Carpentaria town of Port McArthur, the Bureau of Meteorology (BOM) said.
The army and police had already evacuated many communities in the Northern Territory and neighbouring Queensland ahead of Trevor's arrival.
The BOM said Trevor was driving a "very dangerous storm tide" along coastal regions and that heavy rainfall was expected to cause flooding across wide areas of the Northern Territory and Queensland.
Meanwhile another category 4 cyclone, Veronica, was bearing down on the more heavily populated mining region of Pilbara in Western Australia state, where it was expected to make landfall late Saturday or Sunday.
Jonathan Howe of the BOM said Veronica was expected to slow down as it approached the coast near the mining centre of Port Hedland, carrying up to a metre of rain for some areas and pushing a storm surge than could reach four metres (nine feet).
"We could see widespread inundation," of the region, he said.