A firefighter monitors flames as a house burns in the Napa wine region in California, Oct. 9, 2017, as multiple wind-driven fires continue to whip through the region.

Ten people have died in northern California after what officials are describing as an “unprecedented” wild fire that has already destroyed 1,500 structures and devastated large swaths of wine country.

Amy Head, the fire captain spokesperson for Cal Fire, the state agency responsible for fire protection, confirmed the number of fatalities late on Monday.

“We often have multiple fires going on, but the majority of them all started right around same time period, same time of night – it’s unprecedented,” she said. “I hate using that word because it’s been overused a lot lately because of how fires have been in the past few years, but it truly is – there’s just been a lot of destruction.”

California’s governor, Jerry Brown, has declared a state of emergency in eight mostly northern counties – Butte, Lake, Mendocino, Napa, Nevada, Orange, Sonoma and Yuba counties. The flames are barely contained and are threatening thousands of homes and vineyards in the wine country north of San Francisco.

Nine of the deaths occurred in Napa and Sonoma counties, while another was farther north, in Mendocino county, officials said.

The wildfires, whipped by powerful winds early on Monday, sent residents on a headlong flight to safety through smoke and flames as homes burned. Around 20,000 people have been evacuated, including hundreds of senior citizens from local nursing homes.

Entire neighborhoods and a trailer park in the town of Santa Rosa, 55 miles from San Francisco, have already been razed, along with a Hilton hotel, according to local reports.

Officials say the high winds are hampering firefighting efforts in the region about 140 miles (225km) north of San Francisco. To assist with the efforts the country’s largest firefighting aircraft – a converted 747 – has been deployed.

“It was an inferno like you’ve never seen before,” said Marian Williams, who caravanned with neighbors through flames before dawn as one of the wildfires reached the vineyards and ridges at her small Sonoma County town of Kenwood.

Williams could feel the heat of her fire through the car as she fled. “Trees were on fire like torches,” she said.

Mandatory evacuations were ordered in counties north of San Francisco Bay and elsewhere after blazes broke out late on Sunday.

Another Cal Fire spokesperson, Heather Williams, said that 17 major fires had started in the past 24 hours in the California, burning about 94,000 acres, mostly in the northern part of the state. Of those fires, only two are even partly contained, she said; one at just 10% and another at 25%.

She added that unusually high winds had made the fires spread so quickly. “Night-time is when humidity is the highest and temperatures are cooler, but that wind, fueled by denser vegetation, really pushed these fires so quickly.”

The high number of fatalities in one series of connected fires is unusual. There have been, on average, 13 wildfire fatalities a year in the whole of the United States since 2014, according to figures collated by the National Interagency Fire Center.

Head, the Cal Fire captain, said the fires were probably linked to a warming climate. “It has been hotter, it has been drier, our fire seasons have been longer, fires are burning more intensely, which is a direct correlation to the climate changing,” she said.

With so many fires, residents of Sonoma County struggled to figure out what roads to take, finding downed trees or flames blocking some routes.

Fires also burned just to the east in the Napa County wine country as well as in Yuba, Butte and Nevada counties, all north of the state capital. Cal Fire tweeted that as many as 8,000 homes were threatened in Nevada County, which lies on the western slope of the Sierra Nevada.

Smoke was thick in San Francisco, 60 miles (96km) south of the Sonoma County fire.

John Dean, a Sonoma County resident, was driving home early on Monday when “I looked over and saw a house on fire” along the road. Soon he saw more houses engulfed in flames.

Dean sped to his Kenwood home, alerted neighbors, and fled to the town of Sonoma. He was one of hundreds of evacuees who streamed into a 24-hour Safeway market overnight, while authorities set up an official evacuation center.

Maureen McGowan was house-sitting for a brother near Kenwood and said both of the homes on his property were on fire when she left. At the Safeway, she pointed to her feet, still in slippers. She had fled so fast that she hadn’t put on her shoes.

Belia Ramos, chairwoman of the Napa County board of supervisors, said officials did not yet have a count on how many properties were affected, either by the fire directly or by evacuations.

“We’re focusing on making evacuations and trying to keep people safe. We are not prepared to start counting. Certainly with day just breaking now, we are starting to see the structures that are affected,” she said shortly after sunrise.

“The gusts are tremendous and it’s what makes this fire unpredictable. It’s something that we’re having to be very cautious about,” she said.

Pillars of heavy smoke rose from the hills surrounding the town of Napa as the sun set on one of the deadliest days of wildfires in California’s history. As darkness took over, the hills around wine country glowed red.

“We’ve never had a fire like this before,” said Mike Willmarth, a Napa middle school teacher who has lived in the area for 30 years. “We’ve never had devastation like this.”

Willmarth was one of dozens of volunteers staffing an emergency shelter at in the gymnasium of Napa Valley College, where about 100 people rested on blue cots and gathered around the television. With cell service knocked out by the fire, the evacuees were cut off from communication and eager for news of their homes and families.

Margaret Beardsley, 92, sat in a wheelchair next to her husband, Robert, and daughter, Nora. Beardsley used an oxygen tank and wore a surgical mask – the smoke in the air had irritated her lungs.

“It’s terrible,” said Beardsley, who has lived in Napa for 46 years and never been evacuated before. “When we left we had no idea if we would have anything to come back to. I want to go home and sleep in my own bed.”

The lack of information was frustrating George Bradley, 74, a retired cement mason who has lived in the Napa area for his entire life. He hadn’t been able to contact his mother, and was worried about the house he had evacuated around 1:30pm.

“We just paid it off. We just got the deed,” he said. “We don’t know if it’s still standing or not.”

For Erica Miranda, 31, the evacuation had been frightening and unexpected. Miranda, her husband Cristoban Rico, a construction worker, and their three children had evacuated in the afternoon, when their apartment building manager knocked on the door and told them to go.

“I left all my things over there,” Miranda said, “but we are safe here.”

The fire’s economic impact is not yet known – the hundreds of wineries in Napa and Sonoma valleys are their lifeblood. Wine Spectator magazine said that two wineries – Signorello Estate Winery and Paradise Ridge Winery – were destroyed and that portions of another, Stags’ Leap, were also burned.

Although most of this year’s grapes have been harvested, the remaining 20% are some of the most valuable, said Jennifer Putnam, executive director of Napa Valley Grapegrowers, the Napa Valley vineyard trade association. “It’s some of the best fruit that Napa produces, all of the cabernet sauvignon, so it will have a major economic impact if this last 20% can’t be picked,” she said. “We will have to see where we are tomorrow and next week to see how the grapes are metabolizing all this smoke.”

Tom Davies, president and managing partner of the V Sattui Winery, told the Guardian that he may have lost 15 acres out of 300. On Monday morning he spent two hours trying to protect four historic barns on his property, dousing the flames with a hose and shoveling dirt.

“It’s kind of neat we did that but it’s nothing compared to the 1,500 homes and certainly the deaths that are out there – it’s really sad.”

Emergency lines were inundated with callers reporting smoke in the area, prompting officials to ask that the public to “only use 911 if they see actual unattended flames, or are having another emergency”.

The National Weather Service said widespread wind gusts between 35mph and 50mph were observed in the north San Francisco Bay region and isolated spots hit 70mph. The winds were expected to subside at midday.

Community centers, the Sonoma County Fairgrounds and other local centers were opened for evacuees.