A former US Marine combat veteran opened fire in a bar packed with college students in the town on Wednesday night, killing 12 people and stunning a leafy community with a reputation for safety.
Now, the Camp Fire has consumed more than 70,000 acres, and at just 5 percent contained, it is likely to burn through tens of thousands more.
There is no listed containment percentage for the wildfire just yet.
The authorities have issued mandatory and voluntary evacuation orders for Los Angeles's West Hills area.
The town of Chico, population 93,000, could be next in the path of the wildfire, which was forecast to be driven westward overnight by 35-mile-per hour (56 km-per-hour) winds, said Butte County Fire Chief Darren Read.
A third wildfire was also expanding in Southern California's Ventura County. At least nine people died in or near their homes or vehicles as they tried to outrace the "Camp Fire" that started on Thursday morning, has devastated the mountain town of Paradise, about 90 miles north of the state capital, Sacramento.
California Governor-elect Gavin Newsom declared a state of emergency to provide assistance to the fire-hit areas.
Where is the Camp Fire?"It was the event we have feared for a long time", Butte County Sheriff Kory Honea said at a press conference.
"The preliminary investigation revealed that the victims were located in vehicles that were overcome by the Camp Fire", said a statement, adding that they had yet to be identified. Video depicting the evacuation shows traffic moving in a contraflow pattern, with cars flowing in one direction on both sides of the a highway to get people out of harm's way and stalled traffic amidst a hellscape of smoke and flames. Then she reconsidered, thinking: "I'm really scared".
And CalFire Capt. Bill Murphy warned there's likely still more to come.
To the south, hundreds of firefighters have their own hands full with the Woolsey and Hill blazes. By Thursday evening, it had scorched up to 7,000 acres and sent residents of more than 1,200 homes fleeing, the Los Angeles Times reports.
Malibu and the surrounding areas have been hit by many devastating wildfires over the years.
Aside from the winds, low relative humidity in the area was making firefighters' jobs harder, and the area was under a red flag warning Thursday.
The fires are fuelled, as they often are, by a combination of drought-parched wilderness and fierce Santa Ana winds, which blow westward from the desert into California's coastal communities. The National Weather Service does not expect the gusts to subside until later in the day.
He says the fire's pace forced firefighters to focus on life-protection rather than saving structures and he expects that yet-to-be-determined number to be significant. While in Paris to celebrate the 100th anniversary of the end of World War I, Trump took to Twitter and claimed the state's environmental management was "so poor" he may withhold federal payments if no remedy is found.
People fleeing that blaze have cloggedroadways already prone to traffic.
Thousands of residents packed the Pacific Coast Highway to head south or take refuge on beaches, along with their horses and other pets.