The village of La Conchita is along a portion of the coast prone to mudslides, and sits beneath a geologically unstable formation. In 1909, a devastating mudslide occurred approximately one-half mile north of the town, and in 2005 slides closed Highway 101 in both directions, trapping residents.
Sandwiched between a steep, unstable hillside (with the La Conchita Ranch Company situated on the plateau directly over the community), and the Pacific Ocean, La Conchita has been the site of recent major mudslides:
- On March 4, 1995 at 2:03pm, a mudslide buried or damaged seven homes, injuring no one. After the main failure, the weather forecast predicted more rain for the following week.
- On March 10, 1995, a debris flow occurred in the canyon west of the March 4 slide, damaging four or five more residences and a bananaplantation.
- On January 10, 2005 at 12:30pm, a massive mudslide buried four blocks of the town in over 30 feet (9 m) of earth. Ten people were killed by the slide and 14 were injured. Of the 166 homes in the community, fifteen were destroyed and sixteen more were tagged by the county as uninhabitable.
La Conchita Ranch Co. was sued by those affected by the 2005 landslide. A settlement was reached, giving the plaintiffs the company's assets and $5 million.