The Devils Slide (landslide complex) along Coast Highway 1 in San Mateo County, California

Devil's Slide is a notorious landslide area along Coast Highway 1 in San Mateo County. The landslide has been occurring where steeply dipping, faulted and folded sedimentary rocks are slipping above a steeply inclined surface of underlying weathered granite bedrock of Montara Mountain. Several landslide chutes and failure zones are present in the area. The landslide extends from 900 feet (275 m) high on the mountain down to sea level and the glide planes of the slump blocks extend as much as 150 feet (46 m) below the surface. The landslide complex at Devil's Slide has a long and expensive history. Landslide failures disrupted travel along the first road built across the slide area in the late 1890s, and the road was eventually abandoned. Starting in 1905, the Ocean Shore Railroad attempted to operate a rail line across the area below the present road level, but it was abandoned in the 1920s because of the chronic troubles with landsliding at Devil's Slide and elsewhere along this coastal route. The State Department of Highways completed the first version of the coastal highway along the abandoned rail line in 1936 and this is partly the route of Highway 1. However, landsliding and road closures have constantly plagued the route, and millions of dollars have been expended in endless repairs (Williams, 2001).

The URL of this page is http://3dparks.wr.usgs.gov/landslide/big/24.htm