The 15 Freeway reopened Wednesday afternoon after a fast-moving fire in the Cajon Pass prompted the highway’s closure for about four hours.
The fire quickly chewed through 50 acres of brush, causing spot fires that made it difficult to contain.
It was spotted shortly before 11 a.m. after a motorist reported that a big-rig lost a tire and crashed into a tree near Cajon Boulevard and Kenwood Avenue, according to California Highway Patrol logs.
The blaze, called the Keenbrook fire, was burning along the west side of the 15 Freeway near the southbound lanes and rapidly moving north, officials said. The fire initially was reported as about a half-acre and exploded in size in less than two hours, fueled by dry grass and chaparral, U.S. Forest Service spokesman Zach Behrens said.
About 250 firefighters are battling the blaze. An inversion layer sitting over the region trapped a thick layer of black smoke visible for miles, officials said.
An evacuation advisory was issued for Mathews Ranch and structures north of the fire.
Authorities have not determined what sparked the blaze.
4:25 p.m.: This article was updated with the freeway reopening.
1:10 p.m.: This article was updated with increased acreage and additional details from fire officials.
4:15 p.m.: This article was updated to include information about the 15 Freeway reopening.
This article was originally published at 12:35 p.m.