CHICO, Calif. (KGO) -- A chilly, wet Wednesday evening outside wasn't the night before Thanksgiving Jessica Williams had planned.
"It's cold, I'm soaked," Williams said.
MAPS: A look at the Camp Fire in Butte County and other California fires
She, like many evacuees, is now using a tent as shelter following the Camp Fire.
ABC 7 News watched as some relief arrived for her and other evacuees. A group of students dropped off Thanksgiving dinners for them. At least for the moment, things seemed to be looking up, but the same couldn't be said for first responders.
"The rain is of concern for us," Butte County Sheriff Kory Honea said. "Especially the mudflows."
Wednesday was day one of the search for victims in the rain-soaked burn zone.
"I was out there with the searchers and the anthropologists and they still believe that they have a high degree of certainty that if its out there they're going to find it," Sheriff Honea said.
There are still 563 people unaccounted for.
"What we're looking for in many respects is very small bone fragments," Sheriff Honea said.
The fragments can be hard to find as the rain continues to fall.
RELATED: Camp Fire: Rain moves into burn zone as search for victims continues
The weather is slowing the recovery process and could threaten the safety of first responders.
"We'll either remove staff from there or make sure they're aware of it," Sheriff Honea said.
See more stories, photos and videos on the Camp Fire in Butte County.
Rain poses threat to first responders and Camp Fire evacuees