The multi-vehicle collision was reported shortly before 9 a.m. just west of Irwindale Avenue, according to a California Highway Patrol incident log. All westbound lanes were closed, along with three eastbound lanes, snarling traffic in both directions.
The big rig was traveling eastbound when it crashed through the center median and struck a vehicle on the westbound side of the freeway.
A woman was pronounced dead at the scene, a CHP spokesperson said. She was not immediately identified.
Ten people were transported to hospitals, including two who were critically injured and eight with minor injuries, a spokesperson for the Los Angeles County Fire Department said. As many as eight of those patients were juveniles.
Twenty-two other people suffered minor injuries but declined to be taken to a medical center, the spokesperson said.
According to the Highway Patrol, at least three vehicles were involved in the pileup but the precise number was unclear.
In a social media post, the Highway Patrol said lanes would remain closed "for an unknown duration."
The cause of the crash was under investigation.