Lua hit a thinly populated area between Pardoo and Wallal Downs on the Pilbara coast, Sky News Australia reported.
The storm, which has been downgraded from Category 4 to Category 3, was expected to move to the townships of Marble Bar and Nullagine, then pass the town of Newman about midnight.
The Australian Broadcasting Corp. said a red alert -- meaning residents must stay indoors and avoid driving vehicles -- was in effect in coastal communities between Bidyadanga and Port Hedland, including the towns of Port and South Hedland, Marble Bar, Nullagine, and the communities at Yandeyarra and Warralong.
Sky News said authorities hope the storm weakens to a Category 1 by the time in reaches Newman. But even if it does weaken, it's expected to bring heavy winds and rain, threatening widespread flooding.
Meanwhile, authorities had begun evacuating residents from Kalumburu, a remote Western Aboriginal community, because of flooding after heavy rains from a storm in the past week from a monsoon system unrelated to Cyclone Lua.
The Australian Broadcasting Corp. reported 35 adults and six babies were being airlifted to the closest town, Kununurra.