Thousands of people are under evacuation orders in Northern California as some 30 wildfires rage across the state, as Gov. Gavin Newsom declared a statewide emergency in response to the blazes.

A dayslong heat wave with triple-digit temperatures, dry conditions, and storms rolling off the Pacific Ocean with vivid lightning have fueled the blazes.

Newsom said Tuesday he was declaring a statewide emergency to help ensure the availability of vital resources to combat fires burning across the state.

“We are deploying every resource available to keep communities safe as California battles fires across the state during these extreme conditions,” he said in a statement. “California and its federal and local partners are working in lockstep to meet the challenge and remain vigilant in the face of continued dangerous weather conditions.”

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In the northern part of the state, at least seven fires were grouped together as one of two major Lightning Fires, sparked by earlier storms.

Firefighters take refuge in their trucks in a cleared field as a wildfire also known as the Hennessey Fire jumped Knoxville Berryessa Road, west of Sacramento, Calif., Tuesday, Aug. 18, 2020.

Firefighters take refuge in their trucks in a cleared field as a wildfire also known as the Hennessey Fire jumped Knoxville Berryessa Road, west of Sacramento, Calif., Tuesday, Aug. 18, 2020. (Kent Porter/The Press Democrat via AP)

Fire officials have warned of “extreme fire behavior” challenging firefighters, including strong winds.

“Throughout the state of California right now, we are stretched thin for crews," Will Powers, a spokesperson for Cal Fire, told the Associated Press. “Air resources have been stretched thin throughout the whole state.”

The blazes have burned more than 50,000 acres across seven counties in Northern California and the Central Valley.

A wildfire also known as the Hennessey Fire crosses Knoxville Berryessa Road, west of Sacramento, Calif., Tuesday, Aug. 18, 2020.

A wildfire also known as the Hennessey Fire crosses Knoxville Berryessa Road, west of Sacramento, Calif., Tuesday, Aug. 18, 2020. (Kent Porter/The Press Democrat via AP)

Powers said much of the fire was burning through rural areas with steep terrain, making it difficult to get crews in.

Thousands of homes and businesses in the wine-growing counties of Napa and Sonoma were threatened by the uncontrolled blazes.

Flames consume a cabin at the Nichelini Family Winery in unincorporated Napa County as the Hennessey Fire burns on Tuesday, Aug. 18, 2020.

Flames consume a cabin at the Nichelini Family Winery in unincorporated Napa County as the Hennessey Fire burns on Tuesday, Aug. 18, 2020. (AP Photo/Noah Berger)

Police and firefighters went door-to-door late Tuesday in a scramble to make sure everyone was able to escape the flames.

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“I got all my children out, but then I panicked a little bit. It took me a little while to get out,” Diane Bustos told KPIX-TV. “My husband was driving the car and it burned. He got burned and had to leave the car and it blew up. So I was walking down by myself and I got all these flames on me. I lost my shoes. But I made it, God saved me.”

Another large fire burning is known as the SCU Lightning Complex, which is made up of about 20 fires and began early Sunday in areas of Contra Costa, Alameda, Santa Clara, Stanislaus, and San Joaquin counties.

That blaze is still 0% contained.

Former FEMA coordinator Mark Neveau told KTVU at least 59 small fires were sparked by lightning, so many that officials started numbering them instead of naming each.

"What we saw yesterday hadn't happened in 50 years," Neveau said. "That was the number of lightning strikes, up and down the state."

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Blazes have engulfed rural and forest areas near the San Francisco Bay Area, near Salinas in Monterey County, around Oroville Dam north of Sacramento, forested areas west of Silicon Valley, in remote Mendocino County and near the Nevada state line north of Lake Tahoe.

Several also were burning in northern coastline areas and in Southern California.

Excessive heat warnings remain in effect across California and the Desert Southwest. Compared to early in the week, temperatures will drop a couple of degrees. Still, afternoon highs remain well above seasonal averages and dangerously hot.

Forecast high temperatures for Wednesday, Aug. 19, 2020.

Forecast high temperatures for Wednesday, Aug. 19, 2020.

Additionally, red flag warnings remain in effect as a critical wildfire threat continues from northern California into the interior Northwest on Wednesday. Hot, dry, and sometimes windy conditions contribute to the increased chance for wildfire.

The risk of wildfires continues across the West on Wednesday, Aug. 19, 2020.

The risk of wildfires continues across the West on Wednesday, Aug. 19, 2020. (Fox News)

The wildfires have spewed huge columns of smoke and made for unhealthy air, further adding to the misery -- especially in the midst of the coronavirus pandemic.

The cluster of wine country fires threaten an area that only last year grappled with another massive blaze that forced 200,000 to flee — a task made more complicated this year because of the pandemic.

A plume rises over a vineyard in unincorporated Napa County as the Hennessey Fire burns on Tuesday, Aug. 18, 2020.

A plume rises over a vineyard in unincorporated Napa County as the Hennessey Fire burns on Tuesday, Aug. 18, 2020. (AP Photo/Noah Berger)

Tuesday afternoon, the fire was moving toward an area called Atlas Peak that burned in 2017 in a blaze that killed six people and destroyed nearly 800 buildings.

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Robin Sisemore spent Tuesday hosing down vegetation in front of her mother's adjacent house. Both homes were new, replacing ones that burned three years ago in the Atlas Fire

“We can’t have this happen again,” Sisemore’s daughter, Bridget Enge, told the Santa Rosa Press Democrat.

Sisemore and her husband had not yet moved into their home.

“I think my husband had PTSD from the last time, to be honest,” Sisemore said. “He kind of panicked when he saw the smoke and started getting alerts.”

Fox News' Adam Klotz and The Associated Press contributed to this report.