Officials are making grim discoveries -- bodies burnt beyond recognition -- as they search the blackened ruins left by wildfires scorching parts of Northern California.
"Some of them are merely ashes and bones," Sonoma County Sheriff Rob Giordano said at a Thursday press conference. "And we may never get truly confirmative identification on ashes. When you're cremated, you can't get an ID."
Thirty-one people have been killed since the wildfires began Sunday night, making this outbreak one of the deadliest in state history, according to the California Department of Forestry and Fire Protection.
In Sonoma County, authorities had to turn to dental records, fingerprints, tattoos and serial numbers on hip implants to identify victims.
"We've been forced to work that direction because we may not have enough information to identify people, because of the fire and the severity of the burn," Giordano said.
Since Sunday, the deadly fires have leveled thousands of homes and forced evacuations in Northern California's wine country and produced unhealthy air quality in the San Francisco Bay Area.
The biggest fires in Northern California were far from contained.
The 48,000-plus acre Atlas fire in Napa and Solano counties was 27% contained. The 44,000-acre Nuns fire in Sonoma County -- an amalgamation of three recently merged fires north and west of Glen Ellen -- was 5% contained.
• Of the 31 people who were killed by the fires since Sunday night, 17 died in Sonoma County, officials said. Eight people have died in Mendocino County, and at least four in Yuba County and two in Napa County, officials said.
• More than 2,800 residences in Santa Rosa have been destroyed by wildfires, Mayor Chris Coursey told reporters Thursday. The number of destroyed structures in the state exceeds 3,500, Cal Fire says.
• Wildfires have burned more than 221,000 acres throughout California; 17 wildfires remained Friday, Cal Fire said.
• Winds could be especially gusty Friday night through Saturday. Those conditions, joined with low humidity, could spread the flames drastically, the National Weather Service warns. No rain is expected for almost a week.
• The causes of the fires are under investigation. But officials said their spread was aided by strong winds Sunday night, with some gusts of more than 70 mph.
• Almost 8,000 firefighters are trying to contain the blazes, officials said Thursday. They're using 820 firetrucks -- at least 170 from out of state -- 73 helicopters and more than 30 planes.
• About 34,000 utility customers are without electricity service -- and natural gas service to 47,000 customers has been shut off -- mostly in Sonoma and Napa counties, because of the wildfires, the Pacific Gas and Electric Co. said Friday.
At least 400 people are reported missing in Sonoma County alone, where a fire wiped out many homes in Santa Rosa, a city of about 175,000 people some 50 miles northwest of San Francisco.
Deputies are having to wait for houses to cool before they can enter to look for the missing, said Giordano, the sheriff.
The Sonoma County Sheriff's Office identified 10 victims Thursday, and most of them were over 70. The youngest was 57, and the oldest was 95.
Sonoma, Mendocino and Napa counties have been among the hardest hit by the fires. Nearly 20% of the population in those counties is over 65, according to US Census Bureau data.
Evacuees who escaped oncoming flames described harrowing ordeals.
Charity Ruiz, who is pregnant, had been in a car with her family trying to evacuate from their Santa Rosa neighborhood but got stuck in a traffic jam.
"Honestly, I've never in my life felt like I was going to die like that moment," Ruiz told CNN affiliate KPIX. "Not just me, but my girls and unborn baby."
Unable to wait any longer, Ruiz walked back and got her bike from her house and rode out of the neighborhood with her two girls in the toddler trailer.
"I can ride a bike, but I'm pregnant so it was hard," she told the station. Ruiz had been scheduled to deliver her baby next week.
She and her kids made it out of harm's way, but their home burned to the ground.
The fires have been fast and ruthless, shifting without much notice and destroying thousands of structures.
One of them is the Santa Rosa home of Charles Schulz, the creator of the comic strip "Peanuts." Schulz died in 2000.
His widow, Jean, 78, evacuated from the home Monday, shortly before the flames reduced it to rubble, his son Monte Schulz said. The fire destroyed precious reminders of the life his stepmother and his late father had built together, along with memorabilia, Schulz told CNN.
Sleep-deprived firefighters are working to contain the wildfires, even as some of their own homes have been hit.
Many have been working for days with little sleep -- but supervisors are trying to pull them off duty to get rest as firefighters from out of state arrive.
"We are finding people on the line that have just been going to work and staying out there for day after day after day," Napa County Fire Chief Barry Biermann said Thursday. "We're identifying them. We're getting them in as soon as we can to get rest, especially now that we have more reinforcements coming."
Meanwhile, many who lost homes are trying to figure out what to do next. In Yuba County, where a 10,000-acre blaze has killed at least four people, Mariano and Christa Domingo saw the fire approach their fence Sunday night, and they drove away with only one emergency oxygen tank for Christa, who has lung problems, CNN affiliate KOVR reported.
"She was thinking we had to pack up things, and I said, 'No, we don't have any time,' " her husband told the TV station.
Their house was destroyed, and the couple only have clothes they received from a shelter. They said they intend to rebuild their home.
"I'm lucky," Christa Domingo told KOVR. "And I've still got my family."