The road was shut down late Wednesday afternoon after about 10 cubic yards of rock slid into the northbound lane.
Caltrans spokesperson Elizabeth Yelton acknowledged the inconvenience, but says that their main concern is public safety.
Geologists are assessing the stability of the steep rock walls along the roadway to determine what work will be needed to ensure the safety of the public.
“The untrained eye would not be able to determine whether the slope is stable,” said Caltrans Maintenance Area Supervisor Tim McClurg, who has worked on this section of highway for 30 years. “It’s hard to tell what needs to be done just by looking at the fractures in the rock.”
Caltrans has set up a detour around the area.