More than a dozen people were injured in a chain-reaction crash on the 15 Freeway in the Cajon Pass on Wednesday morning as thick fog drastically reduced visibility, authorities said.

Up to 30 cars were involved in the pileup, which shut down southbound lanes of the freeway, triggering a SigAlert, according to the California Highway Patrol and the San Bernardino County Fire Department. Traffic was backed up into the high desert.

“Heavy fog in the area contributing to additional collisions. Multiple resources responding into the area,” the Fire Department said in a tweet.

Traffic is backed up all the way to Hesperia after a pileup in dense fog on the southbound 15 Freeway in the Cajon Pass. (Gina Ferazzi / Los Angeles Times )


The crashes occurred around 10:40 a.m., when two cars collided and became disabled in the roadway, the CHP said. The chain reaction followed.

A dispatcher said the accidents were the result of poor visibility.

Emergency crews transported 10 people with minor to moderate injuries, and seven others were being treated at the scene, she said.

By 11:30 a.m., visibility along the pass had been reduced to about 30 feet, officials said.


All traffic lanes were reopened around 1:30 p.m., according to the California Department of Transportation.

The Cajon Pass lies along one of Southern California’s most vital transportation corridors, connecting the region to Las Vegas and serving as a key east-west shipping route.

Your current driving conditions on hwy 138 and 15 fwy in Cajon pass. Turn on your hazard lights and headlights. Also, SLOW DOWN!!! #dontcrash pic.twitter.com/TPtu8Z8ksK — Lieutenant Bracco (@SBCSDmbracco) May 30, 2018

Motorist Darren Corrigan shares this video of the crash in the Cajon Pass moments after it happened. You can still hear the crash happening. pic.twitter.com/MEwffXog36 — Leticia Juarez (@ABC7Leticia) May 30, 2018


Times staff writer Alene Tchekmedyian contributed to this report.

ruben.vives@latimes.com

joseph.serna@latimes.com

UPDATES:


3:55 p.m.: This article was updated with more information from the CHP.

2:05 p.m.: This article was updated with the opening of all lanes.

12:40 p.m.: This article was updated with details on visibility and the Cajon Pass.

This article was originally published at 12 p.m.