Three days after a landslide destroyed a dozen hillside homes in southern California, the cause of the disaster is still unclear, even as the homes continue their slow descent into a canyon.
Sixteen people have been displaced since the land between the homes began shifting and sliding over the weekend.
Video taken by the Los Angeles county fire department and posted to Twitter showed the devastation to hilltop homes in Rolling Hills Estates, a city of just over 8,000 people about 30 miles south of Los Angeles. The driveways of the affected homes are completely separated from the asphalt they were once connected to and roofs and garages have caved in.
HOMES THREATENED by sliding hillside | FS106 | Pear Tree Ln #RollingHillsEstates | #LACoFD units were on scene monitoring situation. 12 homes evacuated. pic.twitter.com/ruXIhKD82m
— L.A. County Fire Department (@LACoFDPIO) July 9, 2023
Janice Hahn, the LA county supervisor whose district includes Rolling Hills Estates, described the damage as “astonishing”. “There’s nothing we can do, I’ve been told, to stop what’s happening,” Hahn told the Los Angeles Times. “That’s why it’s wait-and-see at that point. Waiting for the homes to fall.”
The county assessor has promised to reassess property values for the homes that have been destroyed and potentially lower or eliminate their property taxes, the city said in an online statement.
The city council of Rolling Hills Estates, where the ground movement is happening, plans to declare a state of emergency on Tuesday.
Rolling Hills Estates was established in 1957 with the goal of maintaining its “rural atmosphere”, characterized by its hilly landscape, according to the city’s website. Today, the upper-middle-class city is largely white and Asian and has a median household income of $160,000, according to the most recent census.
The land beneath the city has been on the radar of geologists for the past 50 years as the sediment that the foundation of the affected homes sits in has slumped, wrinkled and shifted over time.
“Imagine cutting a trench in a cherry pie: all the filling is gonna fall into the hole, and that’s what’s happening here,” Colin Robins, an associate professor of environmental science at Claremont McKenna College, told the Guardian. “Whether it’s due to rainfall or we’ve just crossed a threshold, from a geologic perspective it was a matter of time.”
Some officials have speculated that the barrage of rain that pummeled California late last year and early in 2023 may have led to the landslide. But no one will know the exact cause until a geologist examines the land that has collapsed on Peartree Lane.
Rolling Hills Estates is on the Palos Verdes Peninsula, which sits above the Pacific Ocean and is known for its luxury estates and wineries. Among researchers like Robins, this area is better known for its susceptibility to landslides and soft sediment. In 1956 a landslide destroyed 140 homes in the Portuguese Bend area of the city of Rancho Palos Verdes, also on the peninsula, and earth continues to move there, according to the Associated Press.
