# Palos Verdes Peninsula landslides

The Palos Verdes Peninsula, a coastal region of the Los Angeles metropolitan area, has a long history of landslides and land movements. The Palos Verdes Peninsula is home to the cities of Palos Verdes Estates, Rancho Palos Verdes, Rolling Hills and Rolling Hills Estates, and the unincorporated communities of Academy Hills and Westfield.

## History

As early as the 1920s, the area was identified as a potentially hazardous landslide area, yet real estate construction and development gained traction in the 1940s and 1950s. In 2024, the Palos Verdes Peninsula was rocked with another round of landslides.

## Palos Verdes Estates

In December 2022, a coastal cliff landslide was recorded in Palos Verdes Estates (33.804, -118.394).

## Rancho Palos Verdes

The city of Rancho Palos Verdes sits on four out of five sub-slides of the Ancient Altamira Landslide Complex, also referred to as the Greater Portuguese Bend Landslide Complex. The Complex encompasses four historically active landslide areas within the city limits: Abalone Cove Landslide; Beach Club Landslide; Klondike Canyon Landslide; and Portuguese Bend Landslide; as well as the areas outside of the city’s border of those named landslides.

### 1956 Portuguese Bend Landslide

The Portuguese Bend landslide was activated in 1956, before Rancho Palos Verdes was incorporated as a city. Beginning in September 1956 and continuing until early 1957, the area experienced a landslide concurrent with the construction of a road (the Crenshaw Boulevard extension, south of Crest Road) along the top of an ancient landslide complex. The impacted areas ranged from several acres to roughly two square miles A 1958 video newsreel showed the effects of the landslide’s impact: 140 of the 170 homes in the area were destroyed or displaced.
In 1961, area homeowners filed a lawsuit against Los Angeles County and won a settlement of roughly $10 million.

### Abalone Cove Slide

From 1974 to 1978, an 80 acre landslide occurred in the Abalone Cove area. The lower part of the landslide started to move in February 1974. The "Abalone Cove Slide" was moving so slow that geologists did not verify that it was an actual slide until 1976, after it had damaged roughly twenty homes. It is estimated that the landslides damaged nearly 50 homes and depressed property values.
In 1978, residents noticed cracks on Palos Verdes Drive South, and the upper part of the slide may have started to shift. That same year, the city restricted building new homes in the areas impacted by the landslides, "Landslide Moratorium Map." Since 1980, efforts to control landslide movement have involved removing ground water from the landslide mass.

### Beach Club Landslide

The Portuguese Beach Club landslide is a minor slide within the area's landslide complex. In 2024, residents of Seaview and the Beach Club filed a lawsuit against the City of Rancho Palos Verdes. In 2024, the Beach Club area experienced major deformation along Seawall Road, approximately four to five feet across the beach, and potentially into an offshore slide area.

### Klondike Canyon Landslide

The Klondike Canyon has been noted for landslides. Renewed movement occurred in 1979, and a Geologic Hazard Abatement Districts was created to study the Klondike Canyon landslides in 1982.

### Portuguese Bend and Seaview Landslide

The Portuguese Bend Landslide is a highly active landslide area that covers approximately 240 acres. Since Spring 2023, there has been noticeable land movement and collateral damage in the Portuguese Bend Beach Club, Portuguese Bend Community Association, and Seaview neighborhoods. Several miles of trails have closed in the Abalone Cove Reserve, Filiorum Reserve, Forrestal Reserve, and Portuguese Bend Reserve areas. In September 2024, more than 200 homeowners had to evacuate the Portuguese Bend and Seaview areas. Several homes have collapsed or have been made unlivable. The city issued an evacuation warning for residents; the landslides are moving at a rate of three-fourths to one foot per week. Gas to the Portuguese Bend neighborhood has been shutoff since August 2024. For safety reason, local utility companies planned to terminate all electricity for impacted residents.
On September 3, 2024, California Governor Gavin Newsom declared a state of emergency in the City of Rancho Palos Verdes. The city has extended a construction moratorium for the landslide areas until October 2025.
In Summer 2024, City officials informed residents that they have identified additional land movements and landslides for Rancho Palos Verdes. The new, deeper slide appears to be moving faster and deeper, shifting the city's strategy from individual landslide event response to a broader strategy to address all landslide hazards and issues.

### Portuguese Mud/Landslide Community Infrastructure Resilience Project

In 2023, FEMA awarded a $23.3 million grant to Rancho Palos Verdes for the Portuguese Mud/Landslide Community Infrastructure Resilience Project . The goal of the grant is to make improvements in the existing groundwater extraction systems and to install new subsurface water extraction systems.

### Rancho Palos Verdes Landslide Complex Working Group

The RPV Landslide Complex Working Group meets virtually weekly to plan, coordinate, and implement actions for minimizing land movement and reducing community and property damages. The members of this group include representatives of Abalone Cove Landslide Abatement Districts; California Water Service; City of Rolling Hills; Klondike Canyon Landslide Abatement Districts; Los Angeles County Department of Public Works Sanitary Sewer Maintenance; Los Angeles County Sanitation Districts; Palos Verdes Peninsula Land Conservancy; Portuguese Bend Beach Club Homeowners Association; Portuguese Bend Community Association; Rolling Hills Community Association; Seaview Residential Association; Southern California Gas Company; Southern California Edison; and area residents.

## Rolling Hills
### Flying Triangle Landslide

In 1979, residents in the Flying Triangle Landslide area noticed cracks in the main road leading to their neighborhood. The landslide area spanned approximately 90 acres and damaged and destroyed several homes. Impacted homeowners received roughly $16 million in compensatory setttlements.
In 1987, there was a documented landslide in the Flying Triangle area above Portuguese Bend.

### Rolling Hills Landslide Mitigation Project

In 2024, Congressman Ted Lieu secured one million dollars for the Rolling Hills Landslide Mitigation Project, which is expected to improve wastewater flow and reduce the risk of additional landslides in the Flying Triangle landslide area within the city boundaries.

## Rolling Hills Estates

Rollings Hills Estates is located on the northern side of the Palos Verdes Peninsula, an area that has a history of documented landslides.

### Office Park land movement

In 1997, employees in a Rolling Hills Estates office park witnessed crumbling walls and buckling sidewalks and had to be evacuated.

### Peartree Lane Landslide

On July 8, 2023, the Peartree Lane Landslide destroyed several homes in Rolling Hills Estates. Townhouses in the area slumped into a canyon. This land movement may have started in 2022.