Two people were killed and nine others were injured Saturday in a massive pileup on Interstate 5 in California involving 35 vehicles as thick fog impeded visibility, authorities said.

The deadly pileup occurred on the southbound side of the freeway in Kern County, but both sides were closed and traffic was diverted, the California Department of Transportation, known as Caltrans, said on X.

Caltrans did not provide further details, and the Califonia Highway Patrol and Kern County Fire Department could not be reached for comment.

Emergency responders were called around 7:30 a.m. on a collision report, according to NBC affiliate KGET 17 News in Bakersfield.

Caltrans said the pileup occurred during foggy weather conditions, known in the San Joaquin Valley as Tule fog, which covers the ground in a heavy mist after rain saturates the soil.

Seventeen vehicles and 18 big rigs were involved in the pileup, KBAK reported. Fire department Battalion Chief Jim Calhoun told the station that two people died and nine others were taken to the hospital in unknown conditions.

This article was originally published on NBCNews.com