Update: The 15 Freeway reopened Friday morning through the Cajon Pass. Read an updated version of this story here.
Original post: Authorities say an accident forced the closure of a stretch of the southbound 15 Freeway in the Cajon Pass, jamming traffic for miles as snow fell over the area Thursday night.
The roadway was closed at Oak Hill Road at about 8 p.m., according to Caltrans.
Authorities advised drivers to avoid the Cajon Pass as major traffic delays were expected.
The closure came hours after the northbound lanes of the freeway had been shut down in the same area, which was already experiencing a traffic backup.
State Route 138 was also closed west of the 15 Freeway near Beekley Road due to heavy snowfall in the area.
Video from the Cajon Junction in Phelan showed cars lined bumper to bumper as drivers braced the snow during the Thanksgiving holiday.
It's unknown when the roadway will reopen.
No further details were available.