The crash was reported around 1 a.m. on the northbound side of the freeway.
Some lanes began to reopen around 4:30 a.m. as crews moved some of the vehicles off the roadway.
It's unclear what led to the crash, but the California Highway Patrol told Eyewitness News that two people were sent to the hospital in unknown conditions. Video obtained by ABC7 shows several mangled vehicles on the freeway.
Drivers are being asked to proceed with caution.
This is a developing story. This article will continue to be updated as more information becomes available.