“NASA Data Reveals Growing Threat of Landslides in Rancho Palos Verdes, California”

A string of slow-moving landslides in Rancho Palos Verdes, California, has caused widespread damage and instability in the area, according to new data from NASA. The landslides, which have been steadily creeping toward the sea, have doubled in area since they were first mapped in 2007. The recent data from NASA’s Jet Propulsion Laboratory shows that the landslides have accelerated in recent years, with land in the Palos Verdes Peninsula sliding toward the ocean by as much as four inches each week.

The landslides, known as the Greater Portuguese Bend Landslide Complex, were reactivated in 1956 after road construction destabilized the slope. Heavy rain in 2023 and early 2024 further accelerated the movement of the slides, prompting Governor Gavin Newsom to declare a state of emergency due to the extreme peril to the safety of persons and property. Homes in Rancho Palos Verdes began collapsing in June and August of 2023, with streets fissuring, walls shifting, and floors cracking open.

Mitigating the disaster has been costly, with the city spending over $35 million by the end of the fiscal year to address the landslides. The installation of 11 wells has helped pump out groundwater that could destabilize the slope, resulting in a 3 percent slowdown in the landslide movement between December and February.

While slow-moving landslides are common in California, the behavior of the Rancho Palos Verdes landslides has been unusual. Researchers are still studying the triggers for the increased movement, with wet weather in 2023 being a likely factor. The recent landslides in other parts of Los Angeles County, which moved quickly due to heavy rainfall, have raised concerns about post-fire debris flows in burn scar areas.

Experts believe that while the landslides in Rancho Palos Verdes may continue to cause property damage, the risk of a catastrophic event is low. However, the potential for more landslides to emerge due to increased precipitation under climate change remains a concern. As the world warms, extreme rain events could trigger more landslides, highlighting the need for ongoing research and monitoring of these natural hazards.