More than a dozen bodies, most of which were found severely burned in their cars and houses, were discovered by authorities combing through the wreckage three days after the outbreak of the fire.
The majority of the dead are in Butte County, where a further 110 people have been reported missing, but two bodies were also found in a car in wildfire in south California.
Earlier, nine people were confirmed to have died fleeing flames in the Californian town of Paradise.
About 250,000 people have been ordered to leave their homes in the face of the Hill and Woolsey fires in southern California, including the city of Malibu, home to a number of Hollywood celebrities.
One of those affected was former West Wing actor Martin Sheen, who told Fox affiliate KTTV that the fire was the worst he had ever seen.
He said his house was likely to have been destroyed but that he and his wife Janet were safe and planned to sleep in their car on the beach.
The sheriff’s department in southern California also said two people had been arrested on suspicion of looting properties left behind by those fleeing from the fires.
Also affected is the city of Thousand Oaks, which is still recovering from the recent mass shooting.
By Saturday, fire officials said the Hill fire, which is just over 4,500 acres, was 25% contained but the larger Woolsey fire was still surging.
Los Angeles County fire chief Daryl Osby said thousands of firefighters were working in the toughest, most extreme conditions they had ever seen.
Some 150 homes had been burned and the number was expected to rise, he said.
The other nine deaths were in Paradise, a town of 27,000 in northern California, which was destroyed by fire.
Four of the dead are believed to have perished in their cars, trying to escape flames that moved so fast they left firefighters powerless.
When asked about the cause on Saturday, police at a news conference said “it’s under investigation right now”.
ABC senior meteorologist Rob Marciano told Sky News that a “lull in the winds” was expected on Saturday but would not last long.
“The winds will kick up again tomorrow and again on Monday…There is no rain in the forecast really until further notice.”
Sky News US correspondent Greg Milam, who is in Los Angeles, said: “What’s driving this fire is the Santa Ana winds.
“Usually the winds here come off the water – they are wet and cool. But when they turn, they come from the desert, down through the canyons, and they are dry and unpredictable.
“They come every year and they call them the ‘devil winds’. They are a terrifying and deadly force of nature.”
President Donald Trump has provided emergency funds for Butte, Ventura and Los Angeles counties, and expressed condolences to those fighting the fires and those forced to evacuate.
But he also was also criticised for a tweet that blamed forestry officials for the fire over what he called “gross mismanagement of the forests” and threatened to stop funding forest management.