Flood alerts as Tropical Cyclone Dianne makes landfall

Tropical Cyclone Diane has crossed the WA coast east of Cockatoo Island as a category one system. (Richard Wainwright/AAP PHOTOS)

Rural communities have been warned to brace for days of isolation after Tropical Cyclone Dianne made landfall.

The category one system crossed the coast east of Cockatoo Island in northern Western Australia early on Saturday morning as a category one system and was expected to weaken within hours, the Bureau of Meteorology said.