(Adds comment from expert on forecast rain hampering search for remains, other details)
By Jonathan Allen and Nick Carey
Nov 19 (Reuters) - Emergency services renewed their search through the charred wreckage of California's deadliest ever wildfire for the nearly 1,000 people still unaccounted for on Monday, with rain expected that should help fire crews fighting the blaze but complicate efforts to find its victims.
The remains of 77 people have been recovered, the Butte County Sheriff's Office said late on Sunday, as it cut the number of missing to 993 from 1,276.
The number of missing has fluctuated dramatically over the last week as reports have come in from rescue teams in the field. The sheriff's office said that the number will continue to move up and down as remains are found, more missing reports come in and people who have been reported missing turn up safe.
Some people appear to have been added to the list more than once under variant spellings of their names, the Los Angeles Times reported.
The Camp Fire broke out in northern California on Nov. 8 and quickly all but obliterated Paradise, a mountain town of nearly 27,000 people around 90 miles (150 km) north of the state's capital, Sacramento.
It has burned about 151,000 acres (61,107 hectares) and was 66 percent contained early on Monday, up from 65 percent late on Sunday, the California Department of Forestry and Fire Protection (Cal Fire) said.
Up to four inches (10 cm) of rain is expected to fall north of San Francisco between late Tuesday and Friday, said Patrick Burke, a forecaster at the National Weather Service's Weather Prediction Center in Maryland.
MUDDY, MUSHY MESS
Heavy rain could aid with containing the fire this week, but may also make it harder for teams sifting through ash and dirt looking for bodies.
Colleen Fitzpatrick, founder of the California-based consulting company Identifinders International, said the expected rain will turn the site into a "muddy, mushy mess," slick with wet ash.
"It's going to coat things and stick to things and it's going to make it a lot harder to find remains," she said. "There's really nothing that can be done about this. The workers looking for remains are going to be stuck with this."
Pathologists from the University of Nevada, Reno, worked through the weekend as firefighters peeled back debris, collecting bits of burned bones and photographing everything that might help identify the victims.
The rain also could increase the risk of mudslides in areas where the fire destroyed all vegetation.
"While it isn't an exceptionally strong storm, the recent burns make mud slides on hills and slopes a real danger," the National Weather Service's Burke said.
The storm, which is expected to carry moderate winds of about 15 to 20 mph (24-32 kph), could also cause problems for evacuees, hundreds of whom are sheltering in tents and cars.
The number of people in need of shelter is not clear, but as many as 52,000 people had been ordered to evacuate.
Evacuees sleeping in tents in a Walmart parking lot in Chico, west of Paradise, were moved to shelters on Sunday as that location is prone to flooding, according to local media reports.
Four hundred miles (644 km) south of Sacramento near Malibu, at least two inches of rain are expected to fall on a second fire, the Woolsey. Known to have killed three people, it was 94 percent contained on Monday morning and full containment was expected by Thanksgiving on Thursday.
Malibu's power supply was cut off on Monday to allow for repairs, the Los Angeles County sheriff's office said.
The cause of both fires is under investigation, but electric utilities reported localized equipment problems around the time they broke out.
PG&E Corp has said it could face liability that exceeds its insurance coverage if its equipment were found to have caused the Camp Fire.
Many schools in the San Francisco area were due to remain closed on Monday because of smoke from the Camp Fire, about 170 miles (274 km) to the northeast.
(Reporting by Rich McKay, Jonathan Allen and Nick Carey; writing by Nick Carey; editing by John Stonestreet, Steve Orlofsky and Bill Berkrot)
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