SANTA CRUZ, Calif. — A wildfire was raging outside, but inside the evacuation centers there were risks, too.
Natalie Lyons and Craig Phillips had to make a decision Thursday morning as they sat in their ash-coated Toyota Tundra under the smoky orange sky in Santa Cruz.
After fleeing the small town of Felton on Wednesday as a series of wildfires continued to burn along the Central Coast of California, they sought refuge at the Santa Cruz Civic Auditorium, an evacuation site, but the building was full — and Ms. Lyons was scared of contracting the coronavirus in an enclosed, indoor space.
“There’s some people coughing, their masks are hanging down,” said Ms. Lyons, 54, who said she had lung problems. “I’d rather sleep in my car than end up in a hospital bed.”
So that is exactly what the couple did. Their car served as a makeshift bed across the street from the auditorium, and Ms. Lyons tried to get comfortable in the back seat with their Chihuahua-terrier mix and shellshocked cat. “I hardly got any sleep,” she said.
More than 25,000 people have been forced to evacuate from the rural areas of San Mateo and Santa Cruz Counties, Cal Fire said, and many have struggled to find a place to go, especially with the pandemic still limiting indoor gatherings.
At least five hotels in Santa Cruz said they were filled to capacity on Wednesday night as evacuees sought refuge from the smoke outside. And midday Thursday, Santa Cruz County urged tourists and other visitors to leave so displaced residents could find a bed to sleep in. Even places set up specifically to house evacuees were forced to turn people away because of the need for social distancing, which Jessi Bond, the Civic Auditorium supervisor, called “heartbreaking.”
“There’s really two emergencies happening and we need to address both,” she said.
The fires have killed at least four people. Three bodies were recovered on Thursday from a house that burned down in Napa County, Henry Wofford, a spokesman for the Sheriff’s Office, said. In Solano County, a man who lived on Pleasants Valley Road was found dead during a damage assessment, Sheriff Tom Ferrara said on Facebook.
The wildfires, caused by an extraordinary period of lightning strikes, continued to rage throughout California on Thursday, burning more than 300,000 acres in the state. One group of fires, the L.N.U. Lightning Complex in Napa Valley, grew to 131,000 acres and destroyed more than 100 homes and other buildings, many of them in Vacaville, near Sacramento. Fire officials said on Thursday that they were hopeful they had stopped the fire from spreading further into the city, but more than 30,000 buildings remained threatened.
East of Silicon Valley, a grouping known as the S.C.U. Lightning Complex grew to more than 137,000 acres — nearly the size of Chicago — but has largely been kept away from more populated areas, and firefighters have contained a small portion of it.
The Central Coast fires in Santa Cruz and San Mateo Counties, called the C.Z.U. August Lightning Complex, severely damaged California’s oldest state park, Big Basin Redwoods.
The Santa Cruz County Sheriff’s Office has ordered nearly 28,000 people to leave their homes because of the fire, which swelled to about 40,000 acres on Thursday and remains completely uncontrolled. The University of California, Santa Cruz, campus was placed under a mandatory evacuation order on Thursday night, hours after university officials urged anyone on campus to leave voluntarily.
At least two other people have died in the firefighting effort: a helicopter pilot on a water-dropping mission who was killed in a crash in Fresno County and a worker for Pacific Gas and Electric who had been clearing electrical lines and was found unresponsive in his vehicle in Solano County.
In Santa Cruz, about 40 people were sheltering inside the Civic Auditorium, but Ms. Bond said more than twice that many could have been admitted if spreading the virus was not a concern. Inside, evacuees were dealing with the realities of being forced together during a pandemic: masks at all times and temperature checks at the front door.
Those who were permitted to stay used tents that were spaced throughout the auditorium, a far cry from the dense array of cots that dotted the floor when the building was used as a shelter after the Loma Prieta earthquake in 1989.
“I’m not sure if tent fabric is preventive against Covid,” Ms. Bond said. “But again, just giving people that barrier, that kind of more shelter-in-place type situation rather than being in back-to-back-to-back cots.”
Evacuees further up the coast near Pescadero slept in trailers in parking lots or on the beach overlooking the Pacific Ocean. Others made desperate pleas to family members and friends to take them in, and local authorities said they preferred that people assimilate into so-called quarantine pods rather than brave the virus risks of an indoor shelter. Experts have said the risk of catching the coronavirus is much higher indoors, where still air and enclosed spaces can cause viral particles to concentrate and be inhaled.
Cenaida Perez said she smelled smoke from her house in Vacaville early Wednesday morning and ran outside with her 3-year-old daughter, Adriana. She is currently sheltering at a nearby library, but said she was worried about the coronavirus.
“Who isn’t going to be scared of that virus? It has killed so many,” Ms. Perez, 36, said in Spanish. “But also, I don’t want to die like this, burned to death.”
At the Santa Cruz County Fairgrounds in Watsonville, another evacuation site, RV owners set up camp in parking lots, while others slept in their cars or pitched tents on grass fields amid the smoke. Rachel Muñoz said that she, her husband and two children took a chance and slept in a tent inside a fairground building after evacuating the town of Ben Lomond.
“If I get Covid, it’s probably going to be here,” she said.
But there was not much room to sleep in her pickup truck, which was already occupied by 16 chickens and the pine shavings they nest in.
“These are my babies,” said Ms. Muñoz, 51, while rigging netting to the back of her truck so she could leave the door open and give her hens some fresh air.
The air quality around the Bay Area remained dangerously unhealthy in some places on Thursday. In Concord, northeast of Oakland, the air quality index surpassed 200, meaning the air was “very unhealthy.” The index can reach 500, but anything above 100 is considered unhealthy, particularly for people who have breathing complications.
People should avoid going outside at all, especially to exercise, while the air quality is in the unhealthy range, said Dr. Afif El-Hasan, a lung health specialist in Orange County. He said the smoke could also make people more vulnerable to the coronavirus if they were infected.
“Anything that weakens the lungs, like really bad air, which causes the lungs to lose some of their ability to fight infection, is going to be an issue,” Dr. El-Hasan said. “In theory, breathing in a lot of bad air can make you more susceptible to a more serious Covid illness.”
The double risk of dangerous air and the coronavirus poses a dilemma, Dr. El-Hasan said, making decisions for evacuees even more difficult.
Back in Santa Cruz, Ms. Lyons and Mr. Phillips, her boyfriend, were planning their next move. Mr. Phillips, 65, called one hotel after another, as far away as Monterey, but they all said the same thing: Sorry, we’re full.
He packed his guitars, and she brought pet supplies and DVDs of her daughter’s childhood. The couple said they will be living out of their cars for the foreseeable future.
Mr. Phillips, who retired from his job with a Bay Area air quality agency in April, said the past few months have been far from the easy life he had hoped for.
“I retired into the pandemic, and now homelessness,” he said.
Nicholas Bogel-Burroughs, Giulia McDonnell Nieto del Rio and Lucy Tompkins contributed reporting from New York.