State transportation officials say the highway was closed Monday at Partington Ridge Road and at Lucia after the slide a day earlier.
Crews were assessing the damage, and it was not clear yet when that section of the highway would reopen. Motorists were being advised to take alternate routes.
Meanwhile, another slide that closed Highway 1 at Ragged Point in San Luis Obispo County has been cleared.
There were no reports of any problems on Highway 1 further north.