It was closed overnight between Vista Del Lago Road and Templin Highway because a series of powerful storms triggered the landslide -- undermining the shoulder of the highway.
Caltrans crews are now working to repair the crumbling roadway.
Caltrans released video of crew workers drilling through pavement and lowering steel beams down 50 feet to bedrock to protect the 5 against further landlsides.
"This project will control damage that's been done and then they do plan to conduct permanent repairs in the future," said Officer Alicia Kolter of California Highway Patrol.
For those traveling south, all traffic will be detoured east on State Route 138 to south State Route 14.
The off-ramps and northbound lanes are not affected.
The southbound lanes will close again for repairs Sunday starting at 11p.m. and will reopen 5 a.m. Monday.