The fire is located about a mile northwest of Basalt and was started Tuesday by two people firing tracers at a firing range near Christine Lake.Three houses have been destroyed.
Another fire on the Camp Pendleton Marine base prompted the evacuation of 750 homes. A situation summary from Cal Fire Saturday morning noted "extreme fire behavior with movement in multiple directions".
Excessive heat and fire warnings remain in effect from the National Weather Service across much of California, where crews are battling a number of powerful wildfires. There was little relief overnight.
The new blazes came as Southern California saw many areas top 100 degrees (38 degrees Celsius) Friday and more than a dozen got record-breaking temperatures for the day.
A brush fire that destroyed about 20 homes in Goleta and cause thousands of evacuations reached 80 percent containment Saturday. Five hundred and sixty structures are threatened, including 350 homes in immediate danger, and 15 structures have been destroyed.
The San Francisco Chronicle traced the northern blaze's origins to Thursday, when a resident intentionally lit a small fire on a friend's property near the border with Oregon. Ray Haupt, chairman of the county Board of Supervisors, said losses included homes and livestock. That fire has claimed more than 21,000 acres and is 5 percent contained. Fire bans have also been enacted by many counties.
Los Angeles Fire Department firefighters put out a fire on a garbage truck in the San Fernando Valley section of Los Angeles on Saturday, July 7, 2018. "That gives us the opportunity to get in there and make some really good headway", spokesman Jeff LaRusso of Cal Fire told CNN affiliate KTVL.
Authorities are allowing more Utah residents to return home after a wind-fueled wildfire forced them to flee.
Firefighters have been able to build containment around several destructive wildfires burning in California.
Fire crews announced a better estimate of the damages caused by the Holiday Fire Sunday.
"This one's the 1873 Winchester", he said, studying one of them before turning to another.
The fire has already destroyed 40 structures and killed one person. Authorities said Saturday that afternoon storms could produce flash floods and mudslides in burn scars. Winds are now pushing the fire southwest. The highway had reopened earlier Saturday only to be shut down a short time later due to increased fire activity.