In Southern California, Hilltop Homes Sink Into a Canyon

A dozen hilltop homes in one of the most affluent areas of coastal Los Angeles County were collapsing into a canyon on Monday after a landslide over the weekend forced the evacuation of a neighborhood in the community of Rolling Hills Estates.

Local officials said that about 16 people were evacuated late Saturday after fire officials responding to a call about a leaking pipe discovered “significant land movement” on Peartree Lane on the Palos Verdes Peninsula. California’s disastrously wet winter may be to blame for saturating the underlying soils in the neighborhood, a hazard that in the past few months has threatened other idyllic perches in the state.

After crews found cracks and other damage to homes on the block, authorities said, residents were given 20 minutes to pack up and leave. Gradually, and then swiftly, the properties began to buckle. By Monday afternoon, a stretch of $1 million-plus townhouses that had once stood high on a cliff had slipped nearly to street level, their beige stucco walls slanted and broken, their living areas reduced to gaping holes framed by wooden beams.

Behind yellow caution tape, utility crews inspected power, cable and gas lines. Periodically, a sickening crash and rumble of something cracking or falling would disrupt the quiet of the neighborhood.

“It’s the most shocking thing that I’ve ever seen, and my heart goes out to these people,” Janice Hahn, the Los Angeles County supervisor who represents the area, said at a news conference on Monday. “You can actually hear the snap, crackle and pop every minute when you’re there as each home is shifting and moving — decks are falling off, some of the roofs are now eye level with the ground.”

Ms. Hahn said the cause of the landslide is under investigation, but that the “initial thinking” is that the disaster may be related to the procession of storms that inundated California this winter, isolating tourist destinations, emptying affluent enclaves, flooding farm towns and covering the Sierra Nevada with near-record snowpack.

Spectacularly scenic, with emerald hills and vast views of the Pacific Ocean, the Palos Verdes Peninsula has a soil composition that, in some areas, has made it historically prone to landslides, particularly after wet winters as storm water percolates and destabilizes soil layers far underground.

Alexa Davis, the assistant city manager of Rolling Hills Estates, a community of about 8,300 people, said in an email that the development around Peartree Lane, which was planned and built in the 1970s, is not situated in any of the parts of the peninsula known to be geologically vulnerable. Some nearby areas are so unstable and shot through with sinkholes that even sewer lines have had to be situated aboveground.

“There have been no problems associated with this hillside reported to the city in its 45 years,” Ms. Davis said.

However, Ms. Hahn noted at the news conference that “there is a fissure that snakes through these 10 homes that you can actually see, and they believe that’s what’s causing the earth to pull away and drag these homes along with it into the canyon.” She added that the area was expected to undergo a full examination by soil experts and engineers.

At the top of the street, Gerry Wiegert, 29, helped his mother and stepfather pack their belongings into a black SUV. Next door to their two-story duplex, a garage had collapsed, its door sandwiched between its tile roof and driveway.

“We’re kind of next, if you think about it,” said Mr. Weigert, whose family has rented the three-bedroom home for a decade.

They had moved to the gated neighborhood in Rolling Hills Estates because it felt like a quiet refuge, one with an ocean breeze. It was the kind of place where children played with one another, but residents also enjoyed their privacy.

What may have saved Mr. Wiegert’s home was that it had extra room in the backyard before the drop-off to the valley below — space that some of their neighbors did not have. Erosion has been a commonly discussed problem in the area for a while.

“Cracks were forming here and there,” he said of houses in the neighborhood. “There used to be a trail that existed behind our homes, now it’s just flushed down.”

The past few days have been frustrating, with little help from their landlord, he said. The neighbors in their shared duplex moved out over the weekend. Mr. Wiegert’s family had the feeling that leaving might be the only solution.

So on Monday morning, Mr. Wiegert, who works in accounting, rented out a storage unit and picked up moving boxes. Along with his mother and stepfather, he began gathering up documents, jewelry and mementos. Mr. Wiegert wanted to be sure to grab photos of himself with his namesake: his late father who was also the creator of the Vector supercar.

“I was joking about the situation and then as I’m packing, depression started to hit,” he said. “Hard to say where we’re going next.”