Heavy rain this week could help quench the Camp Fire burning in Northern California, bringing with it an end to the threat of more wildfires this year but also new dangers.
The rain will end "fire concerns for the winter," Robert Baruffaldi, a meteorologist in the National Weather Service's Sacramento office, told CNN Monday night.
However, officials in Butte County are warning residents already devastated by the deadliest and most destructive wildfire in the state's history that rain arriving Wednesday could cause flash flooding and mudflows. The Camp Fire has killed 79 people, 64 of whom authorities have tentatively identified.
The National Weather Service has issued a flash flood watch from Wednesday through Friday for the Camp Fire area.
Evacuees begin preparations ahead of weather
On Monday, fire-weary residents in Butte County prepared themselves for potential flooding.
Jennifer Debrunner, who is staying at the Butte County Fairgrounds in an RV loaned by a stranger, said her family has covered everything her family owns with a tarp. She told CNN affiliate KCRA-TV the rain will bring "a lot of mud, a lot of cold" but she's glad her family has the RV.
Cady Machado told CNN affiliate KTXL-TV she's been staying in a Walmart parking lot with her husband and 9-month-old baby. Because of the incoming rain, Machado says she's sending her child to her sister's home in Arizona. She and her husband have other plans to stay safe from the elements, she said.
"There's a nice bridge with my name on it to go underneath where I won't get flooded out with my husband," she said.
The Red Cross and other organizations have opened additional shelter buildings for people and pets in advance of the rain, KCRA reported.
"We want to make sure those people who are staying in tents know that these spaces are available for them so they can get out of the elements," Shawn Boyd with California's Office of Emergency Services told KCRA.
Rain is expected to arrive in Butte County on Wednesday, bringing about an inch of rain to Paradise, the town virtually wiped out by the Camp Fire, Baruffaldi told CNN. Baruffaldi said the rain may cause "ash flows."
A second rain system arriving Thursday night will bring 1.5 inches of rain to Paradise -- up to 4 inches in areas with higher elevation, Baruffaldi said. It has the potential to create mudflows, he said.
Boyd told KCRA the rain could also help rescue efforts by ridding the air of dust.
"You get rid of the dust, these dogs have a better chance at pinpointing and following their nose to where there may be remains," Boyd said.
As of Monday night, the Camp Fire was 70% contained and had scorched more than 151,000 acres. The fire also has destroyed more than 11,700 homes and torched an area the size of Chicago, according to the California Department of Forestry and Fire Protection .
Fires across the state
Rainfall is also expected in Southern California, where the Woolsey Fire burning west of Los Angeles has killed three people and torched more than 96,000 acres. The burn area is expected to receive less than an inch of rain, bringing the potential for mudslides and minor debris flow from Wednesday afternoon through early Thursday morning, according to the NWS in Los Angeles .
The Woolsey Fire is now 96% contained and expected to be fully contained November 22. Mudslides are more likely in the Woolsey Fire area because fires in the southern part of the state tend to destroy vegetation roots, Baruffaldi said.
Officials in Ventura and Los Angeles counties, where the Woolsey Fire is burning, are urging residents to prepare for the rain. The fire departments in both counties are making an emergency supply of sandbags available to the public at fire stations.
Almost 700 people are unaccounted for
In Butte County, authorities are scrambling to find 699 people who are unaccounted for.
That number keeps fluctuating as residents are located.
"That is raw data we're collecting from phone calls, emails and the 911 system," Butte County Sheriff and Coroner Kory Honea said. "It's not perfect data, but our thought process is that it's better to get that information out to help start getting people accounted for. So rather than wait for perfection, we're trying to get some progress going."
Hundreds of deputies, National Guard troops, coroners and anthropologists are sifting through destroyed homes and scorched cars for human remains. With many retirees living in the Paradise area, officials fear the death toll could rise.
Butte County is keeping a list of the people who are unaccounted for because of the Camp Fire. Honea urged anyone who sees their own name or the name of a loved one found safe to contact the sheriff's office.
Lingering health hazards from the wildfires
The wildfires will hurt the health of people who may never have seen the flames.
Smoke from the Camp Fire hangs heavy in parts of the state, forcing schools to close and shutting down public transportation.
The air quality is so bad that San Francisco, Stockton and Sacramento became the world's three "most polluted cities" on Friday, worse than hot spots in China and India.
People in these areas should minimize the amount of time they spend outside, experts say .