Trees burn on a hillside during the Blue Cut fire near Wrightwood, California US, August 17, 2016. [Photo/Agencies]

The cause of the fire is under investigation.

Authorities said they were forced to close part of Interstate 15, which runs through the Cajon Pass between Las Vegas and the Los Angeles area, and to order about 80,000 residents to evacuate.

Thick columns of smoke blocked out the sky above mountain peaks as the fire overran a number of properties, leaving behind barren lots with blackened appliances and vehicles stripped of nearly everything but metal.

Louis Penna, a spokesman for the San Bernardino County Fire Department, said in an email an official damage estimate was not available but that dozens of destroyed structures were clearly visible.

"There will be a lot of families that come home to nothing," San Bernardino County Fire Chief Mark Hartwig told reporters.

The Los Angeles Times reported hundreds of residents of Wrightwood were staying in their houses, despite dire warnings from authorities.

"It's to the point where explosive fire growth is the new normal this year," Glenn Barley, a fire chief with the San Bernardino unit of Cal-Fire, told reporters.

About 600 miles (970 km) to the northwest, the Clayton Fire, named for a creek near where it broke out, was 40 percent contained after charring 4,000 acres in and around the community of Lower Lake and destroying 175 homes and businesses.

That fire destroyed a 150-year-old Methodist church in the community of Clearlake, according to the Los Angeles Times.

The Chimney Fire, named for its starting point near Chimney Rock Road on San Luis Obispo County, destroyed 40 structures and burned 7,300 acres by Wednesday afternoon, and was 25 percent contained.

As of Aug 12, California had spent $164 million to combat wildfires this year, Tolmachoff said. That was before the Blue Cut, Clayton or Chimney fires had broken out.