The collision was reported shortly before 7 a.m. near Smoke Bear Road, just south of Gorman, according to a California Highway Patrol incident log. A rescue helicopter was dispatched to the scene.
The patient who lost a leg in the crash was rescued by firefighters after being trapped in the wreckage, according to the Los Angeles County Fire Department. That person was transported to a hospital. No other injuries were reported.
One of the big rigs apparently slammed into the back of the other one near the right shoulder, according to video from AIR7 HD. The impact crumpled the trailer of the first vehicle and spilled its payload out onto the ground. The cab of the second semitruck was towed away after being destroyed in the crash.
Southbound traffic was backed up as the CHP conducted a preliminary investigation. All lanes were reopened Wednesday evening.
The cause of the incident was unknown.