As the death toll from the Camp Fire rose to 63 people, rescue workers searching for human remains in the wreckage hope that hundreds of people who are still unaccounted for after the blaze are still alive.
After going through a week of 911 calls, authorities announced Thursday they are looking into reports of 631 people who are possibly missing.
"You have to understand, this is a dynamic list," Butte County Sheriff and Coroner Kory Honea said Thursday evening. "Some days might be less people, some days might be more people, but my hope at the end of the day, we have accounted for everybody. "
Photos: Wildfires devastation in California
A week after two major wildfires sparked at both ends of the Golden State, the total death toll has increased to 66, fire officials said.
The Camp Fire -- now the deadliest and most destructive wildfire in the state -- has left 63 people dead, destroyed about 9,700 homes and scorched 141,000 acres. By Thursday night, it was 40% contained.
Hundreds of deputies, National Guard troops and coroners are sifting through leveled homes and mangled cars for human remains.
"They are going to be searching vehicles that have been burned. They'll be searching residences that have been burned. Checking around the residences ... our mission is to find the victims from this fire, recover them and get them identified and notify the families to give them some answers," Butte County Sheriff's Investigations Sgt. Steve Collins said.
President Donald Trump is expected to visit the region Saturday as firefighters continue battling the blaze.
66 total deaths statewide
Meanwhile, the Woolsey Fire in Southern California has claimed three lives and destroyed 548 structures in Los Angeles and Ventura counties, Cal Fire said.
More than a week since firefighters began battling the blaze, more than 98,000 acres have been burned, evacuees remain in shelters and portions of Malibu and nearby areas "must be completely rebuilt," officials said.
More than 3,300 firefighters continue making progress against the massive wildfire, which was 62% contained as of Thursday.
Several mandatory evacuations remain in place late Thursday due to the amount of burned power poles, damaged power lines and destroyed roads.
More than 230,000 acres burned in California in the past week. That's larger than the cities of Chicago and Boston combined. And in 30 days, firefighters have battled more than 500 blazes, said Cal Fire, the state's forestry and fire protection agency.
Scores reported missing
The number of names on the missing list for the Camp Fire soared Thursday but authorities say they are still struggling to confirm whether all of them are still unaccounted.
Honea said investigators combined all the information they have received from callers since the day the fire erupted. Some of the names on the list made public by Butte County officials appear more than once and it's not clear if any are duplicates, Honea said.
The cell phone service is unreliable and evacuees have not reached out to relatives and others don't know they were reported missing.
Officials have said it's hard to determine the number of missing. Some people who may have evacuated can't be reached because cell phone service is unreliable. Some have not reached out to relatives and they may not know someone is looking for them, Honea said.
For two days, Paradise Police Officer Matthew Gates searched through ash and collapsed buildings for the remains of a woman.
When the Camp Fire broke out, a man told Gates her mother was likely driving on a jammed roadway that hundreds in Paradise used to flee the flames. But Gates couldn't find her.
Then, Gates found her at a shelter for evacuees.
"She had burns up her arms and I knew it was her," Gates told CNN affiliate KRCR. "I went and gave her a hug because I've been looking for her body."
Authorities are trying to reach those who called 911 since the fire started in order to verify if they've made contact with their loved ones, said Butte County Sheriff's Investigations Sgt. Steve Collins.
"We're asking people to call us if they do come in contact with their loved one so that we don't spend time looking for somebody that's already found," Collins said.
Families who lost their homes in the fires are going to have a very hard time finding a place to live, Butte County Housing Authority Executive Director Ed Mayer said.
"We just had 10% of our county's housing stock erased in one day; it's hard to convey the significance of that," he said.
A Walmart in Chico has a parking lot full of vehicles, including motor homes, in which people are living, often running the heat in their cars and trucks all night. Other people are staying in tents.
"It's been a week and people have been great, but I don't know how long it's going to last," Mayer said. "Short-term, we are fine, but long-term we are not."
One of the selling points of Paradise was its affordable housing, but that's been erased, Mayer said.
"And there is nothing to replace it" for low-income families, he said.
Adding to the misery for evacuees, officials reported a suspected outbreak of norovirus at a shelter in Chico. Evacuees showed some symptoms, but officials are waiting for test results for confirmation.The stomach bug causes vomiting, nausea and diarrhea.