The Palos Verdes landslide is not one event — it is a 70-year (and counting) chapter of an ancient story written into the rock of the peninsula itself.
The Palos Verdes Hills are a fault-bounded block of Cenozoic sedimentary and volcanic rocks draped over a core of much older Mesozoic schist. The critical weakness lies in the Altamira Shale member of the Miocene Monterey Formation — layers that contain thin seams of bentonite clay, formed from ancient volcanic ash.
When bentonite gets wet, it becomes extraordinarily slippery. On the peninsula's south slope these weak layers dip seaward, roughly parallel to the ground surface — a natural slide ramp aimed at the ocean. Wet winters raise groundwater, pressurize and lubricate those clay seams, and the hillside above them creeps toward the sea. That is why nearly every intervention — dewatering wells, hydraugers, winterization ditches — targets one thing: getting water out of the slide mass.
All four sit within (and are "inset into") the much larger dormant ancient Portuguese Bend landslide complex mapped by the California Geological Survey. See the schematic map of the complex to visualize how they fit together.
Massive prehistoric sliding creates a roughly two-square-mile landslide complex on the peninsula's south flank. It eventually goes dormant, leaving hummocky terrain later called Portuguese Bend.
During extension of Crenshaw Boulevard, Los Angeles County crews place over 300,000 cubic yards of fill on the head of the ancient slide. The eastern portion reactivates. Roughly 130 homes are ultimately destroyed or removed in the Portuguese Bend community, and litigation against the County follows. The land has not stopped moving since.
A second lobe of the ancient complex, west of Portuguese Bend, starts sliding — threatening homes above Abalone Cove and Palos Verdes Drive South.
The Klondike Canyon slide begins moving near the Seaview neighborhood. Under California's Beverly Act, property owners form two Geologic Hazard Abatement Districts — ACLAD (Abalone Cove, 1981) and KCLAD (Klondike Canyon, 1981) — to fund and operate dewatering wells and drainage. Early dewatering succeeds in dramatically slowing Abalone Cove.
Portuguese Bend creeps on — bending Palos Verdes Drive South, which the City repairs continuously. The City adopts a landslide moratorium restricting new development in the moving area, studies remediation options, and installs GPS monitoring. Movement waxes with wet winters and wanes with dry ones.
Historic storms saturate the peninsula. Movement accelerates across the complex; fissures open in the Portuguese Bend Reserve; the City declares a local emergency and begins winterization measures.
The four slides begin moving as one broad mass across ~700 acres — in places several inches per week, with NASA/JPL radar measuring up to ~4 inches per week in residential areas that fall. The Wayfarers Chapel closes in February and is dismantled for preservation by September. Power is cut to about 245 homes and gas to entire neighborhoods. FEMA and Cal OES announce a $42 million voluntary buyout program in October. Deep dewatering wells begin pumping at the slide's toe.
Dewatering removes hundreds of millions of gallons; movement decelerates sharply. Seaview and the Beach Club effectively stop moving; gas restoration begins in Seaview; the City's $2.8M financial assistance program pays out to 223 households; seven additional wells are installed with ACLAD and KCLAD; the ~$33M remediation project moves through environmental review.
By July 2026 the complex is moving 60% slower than a year earlier, averaging about 1.1 inches per week in the still-active interior. Buyouts inch forward awaiting FEMA awards, the Council debates a third abatement district for Portuguese Bend, and dewatering passes half a billion gallons removed. The emergency — and the management effort — continues.
Lloyd Wright's 1951 "glass church," a National Historic Landmark, closed in February 2024 as land movement warped its structures. It was meticulously dismantled — thousands of parts catalogued and stored — with a prospective new campus identified at Battery Barnes near Rancho Palos Verdes City Hall, about 1.7 miles from its original site.
The coastal road crossing the slide is among the most-repaired stretches of pavement in California — inspected constantly, repaved repeatedly, and now the subject of a planned regrading project. In the 2024 acceleration it deformed dramatically, at times requiring escorts and overnight closures.
The beloved open-space preserve above the slide saw trails torn by fissures and scarps during the acceleration, forcing extended closures and permanently altering some routes. It remains the clearest place to see the landslide's raw geology.