More than 80,000 people are being evacuated from their homes in Southern California, as a fast-moving wildfire continues to grow.
The so-called Blue Cut Fire broke out on Tuesday in a mountain pass and quickly grew to more than 6500 acres, prompting authorities to order the evacuation of 82,000 locals.
Part of the main freeway between the Los Angeles area and Las Vegas has also been closed by officials.
The fire erupted in heavy brush just west of Interstate 15 between the towns of Crestline and Hesperia, about 160km east of Los Angeles.
"It is a very fast-moving fire, it has wind behind it," said US Forest Service spokeswoman Lyn Sieliet.
The cause of the blaze is under investigation.
It is the latest in a series of wildfires that have blackened nearly 300,000 acres of the drought-parched US West.
Ms Sieliet said the Blue Cut Fire, despite efforts by 700 firefighters to control it, had damaged structures in the Cajon Pass.
San Bernardino County sheriff's deputies were going door-to-door in the community of Wrightwood and nearby areas to tell residents to evacuate, said sheriff's spokeswoman Cindy Bachman.
The eruption of the Blue Cut Fire came as crews more than 970km to the northwest began to make headway on Tuesday against a Northern California wildfire that has destroyed more than 175 homes and businesses.
The so-called Clayton Fire was 20 percent contained as of Tuesday afternoon (US time), according to the California Department of Forestry and Fire Protection. It has charred more than 4000 acres in and around the community of Lower Lake, forcing hundreds of people to flee.
Authorities on Monday arrested 40-year-old Damin Pashilk on suspicion of setting that blaze and numerous others in the area over the past year. He is scheduled to appear in court on Wednesday.
The Clayton Fire, which threatened about 1500 structures, was driven by fierce winds after sparking on Saturday evening. There were no reports of casualties.
On Monday, California Governor Jerry Brown declared states of emergency for the Clayton Fire and another in Central California, the so-called Chimney Fire, allowing local officials to get help from agencies statewide.
The Chimney Fire was just 10 percent contained by Tuesday afternoon after scorching 6400 acres since erupting on Saturday. It has destroyed 12 structures and forced hundreds of residents to evacuate.