While the predicted downpours could help tamp down blazes that have killed 77 people so far, they also could wash away telltale fragments of bone, or turn loose, dry ash into a thick paste that would frustrate the search.
A team of 10 volunteers went from burned house to burned house Sunday in the devastated town of Paradise, accompanied by a cadaver dog with a bell on its collar that jingled in the grim landscape.
The members of the team scrutinized the rubble in five-minute sweeps, using sticks to move aside debris and focused on vehicles, bathtubs and what was left of mattresses. When no remains were found, they spray-painted a large, orange "0'' near the house.
Up to 400 people were involved in the overall search and recovery effort. Robert Panak, a volunteer on a different team from Napa County, spent the morning searching homes, but didn't find any remains.
Asked whether the job was tough, the 50-year-old volunteer said, "I just think about the positives, bringing relief to the families, closure."
He said his approach was to try to picture the house before it burned and think where people might have hidden.
Nearly 1,300 names are on a list of people unaccounted for more than a week after the fire began in Butte County, authorities said late Saturday. They stressed that the long roster does not mean they believe all those on the list are missing.
Sheriff Kory Honea pleaded with evacuees to review the list of those reported as unreachable by family and friends and to call the department if those people are known to be safe.
Deputies have located hundreds of people to date, but the overall number keeps growing because they are adding more names, including those from the chaotic early hours of the disaster, Honea said.
"As much as I wish that we could get through all of this before the rains come, I don't know if that's possible," he said.
Honea said it was within the "realm of possibility" that officials would never know the exact death toll from the blaze.
On Sunday afternoon, more than 50 people gathered at a memorial for the victims at First Christian Church in Chico, where a banner on the altar read, "We will rise from the ashes."
People hugged and shed tears as Pastor Jesse Kearns recited a prayer for first responders: "We ask for continued strength as they are growing weary right now."
Hundreds of search and recovery personnel are involved in the effort, going to homes when they receive tips that someone might have died there.
But they are also doing a more comprehensive, "door-to-door" and "car-to-car" search of areas, said Joe Moses, a commander with the Monterey County Sheriff's Office, who is helping oversee the search and rescue effort.
The search area is huge, Moses said, with many structures that need to be checked.
The fire also burned many places to the ground, creating a landscape unique to many search-and- rescue personnel, he said.
"Here we're looking for very small parts and pieces, and so we have to be very diligent and systematic in how we do your searches," he said Friday.
The remains of five more people were found Saturday, including four in Paradise and one in nearby Concow, bringing the number of dead to 77.
Among them was Lolene Rios, 56, whose son, Jed, tearfully told KXTV in Sacramento that his mother had an "endless amount of love" for him.
President Donald Trump toured the area Saturday, joined by California's outgoing and incoming governors, both Democrats who have traded sharp barbs with the Republican administration. Trump also visited Southern California, where firefighters were making progress on a wildfire that tore through communities west of Los Angeles from Thousand Oaks to Malibu, killing three people.
"We've never seen anything like this in California; we've never seen anything like this yet. It's like total devastation," Trump said as he stood amid the ruins of Paradise and pledged the full support of the federal government.
Soon after the fire began, Trump blamed state officials for poor forest management and threatened to cut off federal funding.
"He's got our back," outgoing Gov. Jerry Brown said Sunday on CBS' "Face the Nation."
"There have been some back and forth between California leaders and the president," Brown said. "But in the face of tragedy, people tend to rise above some of their lesser propensities. So I think we're on a good path."
He also suggested California's severe wildfires will make believers of even the most ardent climate change skeptics "in less than five years," and that those living near forests might need to build underground shelters to protect them from fires.
Rain was forecast for midweek in the Paradise area. The National Weather Service said the area could get 20 mph (32 kph) sustained winds and 40 mph (64 kph) gusts, which could make it hard for crews to keep making progress against the blaze.
Northern California's Camp Fire has destroyed about 10,500 homes and torched 233 square miles (603 square kilometers). It was 65 percent contained.
Honea expressed hope that Trump's visit would help with recovery, saying the tour by the Republican president and California's Democratic leaders "signals a spirit of cooperation here that ultimately benefit this community and get us on a path toward recovery."