California wildfires: Rain helps ensure Camp Fire blaze is nearly fully contained although hundreds remain missing

More showers are expected over the weekend

(Rex Features)

More rain is forecast for northern California over the weekend after helping firefighters nearly fully contain one of the state's deadliest wildfires, which has killed at least 84 people.

After a particularly rainless year, the so-called Camp Fire has ravaged most of the town of Paradise and left hundreds still missing.

An inch and a half of rain graced the area on Wednesday, helping to nearly extinguish the blaze which is now 95 per cent contained. Rain also helped reduce the Woolsey fire in Southern California - which has killed three people. That blaze is now reported to be 100 per cent contained.

Between one to three inches (2.5-7.5cm) of rain is expected to fall between Friday and Sunday, adding to the three inches that already fell this week, the National Weather Service (NWS) said.

"Flash floods and debris flows will be a particular threat in the wildfire burn areas," the NWS said in a notice warning of the risk of flash floods through Friday. "Heavy rainfall at times is possible over the burn areas with the greatest threat expected today."

Fire scars leave land with little to no vegetation to stem potential flooding, rock slides, mud slides, and debris flows.

As many as 560 people are still unaccounted for. That number has fluctuated widely over the past week, hitting a high of more than 1,200 over last weekend.

Many of those missing are believed to be aged 65 and over.

Rain has the potential of complicating rescue and recovery efforts as well. Firefighters and rescue workers have to deal with muddy and unstable ground.

The National Oceanic and Atmospheric Administration also issued a flash flood watch warning and wind advisory for Butte County and other areas that the Camp Fire have affected.

That risk is low for thousands of evacuees who have fled the Camp Fire and are sheltering outside areas prone to mudslides.

Reuters contributed to this report