LOS ANGELES — Crews working around the clock cleared boulders, trees, and crushed cars from all lanes of US 101, but California officials said the road will remain closed for at least another week because of mudslides that have left 20 dead.

Jim Shivers, a spokesman for the California Department of Transportation, said Monday that officials are aiming to reopen the highway near the devastated town of Montecito on Jan. 22.

Much of the water on the roadway had receded by Sunday, allowing workers to use bulldozers and other equipment to push away solid debris that was still several feet deep.

‘‘It is not until you can see the damage with your own eyes that you can come to understand the magnitude of the incident, the response that is necessary, but most importantly the impact to the citizens and families of Santa Barbara County,’’ Shivers said.

Four people remained missing after the mudslides were triggered Jan. 9 by a powerful storm that swept in from the Pacific and dumped a deluge on mountain slopes that had been burned bare by a huge wildfire in December.

Search and rescue operations ended over the weekend, and authorities transitioned to recovery.

ASSOCIATED PRESS