Two people were killed and nine others were injured in a 35-vehicle pileup on Interstate 5 in Bakersfield, California, on Saturday morning.

The pileup involved 17 cars and 18 big rigs, KABC reported. The California Highway Patrol did not respond to USA TODAY's request for comment. 

KBAK reported that the crash happened at around 7:30 a.m. on Saturday on the southbound lanes. 

The California Department of Transportation said the southbound lanes between SR-223 and Older River Road will be closed until further notice. Crews were working throughout the night to investigate and clean up the scene.

Foggy conditions may have played a role

CHP Buttonwillow PIO Manny Garcia told KBAK that fog may have played a role in the pileup.

"All the witnesses have fog visibility at approximately 100 feet at the time, so there was heavy fog at the time of the collision," Garcia said.

Jim Calhoun with the Kern County Fire Department told KGET that by the time fire crews arrived at the "chaotic" scene, the visibility was down to about 10 feet.

Yesenia Cruz, a driver involved in the pileup, told KBAK that she stopped after being notified of a crash on her GPS. Two minutes later, the car behind her crashed into her and "that's when everything just happened fast."

"Everybody just started screaming for help, just like that, and there were little kids as well crying," Cruz said.

Calhoun told KGET that the crash site was about half a mile long. Fire responders treated the most severely injured patients first.