Authorities in northern California, United States ordered 180,000 residents to evacuate their homes on Sunday as winds fuelled a wildfire in the wine country, while electricity was shut off for millions of people in an effort to prevent more fires.

The fear that the winds could blow embers and spread fire across a major highway prompted authorities to expand evacuation orders that covered parts of Santa Rosa, a city of 175,000 that was devastated by a wildfire two years ago.

The latest evacuation orders came after Pacific Gas and Electric shut off power to 2.3 million people across 38 counties starting on Saturday evening.

About 90,000 residents were already under a mandatory evacuation order on Saturday night that encompassed a huge swath of wine country stretching from the inland community of Healdsburg West through the Russian River Valley and to Bodega Bay on the coast, Sonoma County Sheriff Mark Essick said.

The current wildfire, dubbed the Kincade Fire, began on Wednesday night and is only 10 percent contained, the California Department of Forestry and Fire Protection said on Sunday. It grew by almost 4,000 acres (1,618 hectares) overnight to 120 square kilometres (47 square miles) and has destroyed 79 structures.