California Division of Mines and Geology

Geologic mapping and El Niño in southern California:

Examples of landslides and debris flows in coastal southern California

Landslides and debris flows--Santa Monica, San Gabriel, and San Bernardino Mountains (photos by Douglas M. Morton)

Airplane photo of scars (pale stripes) from soil slips that developed into short-distance run-out debris flows. These debris flows, located in the Ventura area, originated during long-duration and intense winter storms in 1980.

Cabin nearly buried by debris flows in 1969 at Wrightwood, located in the eastern San Gabriel Mountains. Water that produced these debris flows was from the spring melting of snow on a landslide on the mountain south of Wrightwood. Debris flows moved as fast as 8 miles per hour, with a new flow every few minutes.

Homes on the north side of San Bernardino, winter of 1980. The nearest homes are buried nearly to the roofs by debris flows that come from an area above the homes burned in 1980. Debris flows filled and overran the flood control basin located in the foreground, which has been partly cleaned out at the time the photo was taken.

Home in the Monterey Park area destroyed by a small debris flow during the winter of 1980. Note the short distance down slope this narrow debris flow traveled. Side view of the home and debris flow path.

Homes in the Monterey Park area destroyed by coalesced small debris flows produced by the winter storms of 1980.

Huge boulder transported by a debris flow produced during an intense, short-duration summer rain ­ "cloud burst" ­ in the Barton Flats area of the San Bernardino Mountains, in the 1960s.

Landslides and debris flows--Pacific Palisades areas (photos from USGS archives)

Sea cliffs at Pacific Palisades are made up of easily eroded siltstone, and have experienced many landslides over the past few decades.

Photo taken 2/4/56 at Via de las Olas Palisades showing landslide that crossed highway onto beaches. Note prominent scarp at headwall of slide on right.

Photo taken 3/27/58 at Via de las Olas Palisades showing landslide that crossed highway onto beaches. Note prominent scarp at headwall of slide on right. Compare with earlier photo taken in 1956.

Photo taken 11/2/56 at De Pauw Street, Potrero Canyon, showing house perched overhanging a cliff created by landsliding.

Photo taken 4/1/69 at Friends Street, Potrero Canyon, showing street damage and house perched overhanging a cliff created by landsliding.

Photo taken 3/11/60 at Porto Marina Way. Mudflows drape the cliff face.

Geologic mapping in southern California

For further information, contact David Miller

http://geology.wr.usgs.gov/wgmt/elnino/scampen/examples.html, 29 December 1997, Contact: El Niño Web Team