Authorities in northern California have ordered 180,000 residents to flee their homes, as the government declared a “statewide emergency”. 

It’s feared “unprecedented” fierce winds could blow embers and spread the fire across a major road 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 & Electric shut off power to 2.3 million people across 38 countries starting on Saturday evening.

“This is the largest evacuation that any of us … can remember,” the Sonoma County Sheriff’s Office tweeted.

“Take care of each other.”

#RedFlagWarning in effect today through Monday throughout Northern California and Los Angeles area due to gusty winds and low humidity. This is #CriticalFireWeather and caution should be used when outdoors. https://t.co/YfyyGv21bb pic.twitter.com/PHxotkRls7

— CAL FIRE (@CAL_FIRE) October 27, 2019

About 90,000 residents were already under a mandatory evacuation order on Saturday night that encompassed a huge swathe 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 sheriff pleaded with residents in the evacuation zone to get out immediately, citing the 24 lives lost when a wildfire swept through the region two years ago.

“I’m seeing people reporting that they’re going to stay and fight this fire,” Mr Essick said.

“You cannot fight this. Please evacuate.”

JUST IN: California Gov. Gavin Newsom declares statewide emergency due to fires: "Governor Gavin Newsom declared a statewide emergency due to the effects of unprecedented high-wind events which have resulted in fires and evacuations across the state." https://t.co/1NKWh5U8yg pic.twitter.com/fFC9i6ufkL

— ABC News (@ABC) October 27, 2019

The current wildfire, dubbed the Kincade Fire, began on Wednesday night and is only 10 per cent contained, the California Department of Forestry and Fire Protection said on Sunday.

It grew by almost 1600ha overnight to 12,000ha and has destroyed 79 structures.

The fire was expected to be especially unwieldy on Sunday because of powerful winds.

On Sunday morning, the National Weather Service reported wind gusts topped 144km/h in Healdsburg Hills North, a popular tourist attraction in northern California’s wine country.

Winds could lead to “erratic fire behaviour” and send embers for miles, Cal Fire warned.

Healdsburg lost one of its historic attractions to the flames on Sunday when embers carried by the winds sparked a blaze that engulfed the Soda Rock Winery whose buildings included a general store and post office founded in 1869.

Concern that gusts could knock down power lines and spark devastating wildfires prompted two blackouts in recent weeks.

PG&E said the new wave of blackouts was affecting about 940,000 homes and businesses in 36 counties for 48 hours or longer.

The city of San Francisco was not in line for a blackout amid shut-offs for most of the rest of the San Francisco Bay Area, the wine country to the north and the Sierra foothills.

Evacuations also hit inmates at the North County Detention Facility in Santa Rosa and about 100 Sutter Santa Rosa Regional Hospital patients.

Authorities expanded evacuation orders to Santa Rosa out of fear that blowing embers could spread the fire across US 101, the main thoroughfare in the area, and march towards the coast.

“The concern is that it may jump the freeway,” said Brandon Halle, a spokesman with the California Department of Forestry and Fire Protection.

“We’re focused on getting ahead of this fire.”

To the south, a wildfire on Thursday destroyed 18 structures in the Santa Clarita area north of Los Angeles.

Nearly all the 50,000 residents ordered to evacuate were allowed back home after Santa Ana winds began to ease.

Sheriff’s officials said human remains were found within the wide burn area, but it is unclear if the death is connected to the blaze.

What sparked the current fires is unknown, but PG&E said a 230,000-volt transmission line near Geyserville malfunctioned minutes before that blaze erupted on Wednesday night.

The possible link between the wine country fire and a PG&E transmission line contained grim parallels to last year when most of the town of Paradise burned, killing 85 people in the deadliest US blaze in a century.

State officials concluded a PG&E transmission line sparked that fire.