Home Care In Palos Verdes Peninsula, CA

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On a beautiful July day earlier this year, out of the blue, catastrophe visited residents of Rolling Hills Estates on the Palos Verdes Peninsula.

It’d been about four months since the last heavy rains, but the precipitation from one of the wettest years on record appears to have been working its way deep into the earth.

It appears that raindrops percolated through the silt and sand and past deposits of volcanic ash in the Altamira Shale, before settling on layers of montmorillonite rich clays, lifted from the ocean during the Pliocene some three million years ago.

It's possible that the particles of clay then took on the water, compromising the ability of the earth beneath the homes to stick together, leading them to separate like an unevenly stacked layer cake. The constituent parts of the neighborhood – the homes, streets and sewer – began to move, pulled by gravity down an embankment into the canyon below.

A preliminary report compiled for the city of Rolling Hills Estates by the geotechnical firm GeoKinetics said that a "high level of precipitation" was likely the main factor behind the slope failure. Though, it should be noted, other inquiries are ongoing.

If you know a bit about the area, landslides should come as little surprise, especially considering there are roughly 150 others that've have been documented there.

“Is the geology conducive to land sliding along the Palos Verdes Peninsula? The answer is yes,” said Jeremy Lancaster, state geologist and director of the California Geological Survey.

Given that another year of heavy rain might be on the way, influenced by a strong El Niño, what are the odds we’ll see even more homes sliding into canyons below?

Can we predict landslides?

There are two key types of landslides that you should be aware of: shallow and deep seated landslides.

The one's I'm usually on LAist screaming about are the shallow ones, particularly in hilly areas that've just burned. They're a bit more predictable because we know that after a fire, hillsides are covered in a waxy, water repelling layer and have had most of their vegetation removed. So, when rain falls from the sky, there's not much to slow it down, keep it from knocking dirt loose, picking up speed and turning into a huge destructive wall of water, like what we saw in Montecito in 2018.

When reporting on landslide risk during major storms, I'm usually on the lookout for recently burned areas anticipated to receive an inch of rain per hour, because heavy rainfall makes the shallow slides more likely.

Deep–seated landslides, like what we often see in the Palos Verdes Peninsula are a whole other beast,

We know that they typically need three things to occur: steep slopes, weak rocks and some sort of triggering mechanism, such as earthquakes or water (the peninsula has all three), to get them going.

The Brief

But unless there's apparent movement on the surface, they're terribly difficult to anticipate because it's unclear what's going on deep in the ground. As soon as you're dealing with layer upon layer of material from different epochs all stacked upon each other, things get much more complex.

All it takes is one weak layer of water loving clay to give out between a whole bunch of big strong rock, for a whole hillside to come down.

Terrifyingly, a deep slide can occur months after a rainy season ends because it can take water a long time to slowly percolate through the earth to get to one of those weak layers.

"Because these landslides are at greater depths, it's really difficult geologically to have precise controls on when and how exactly that motion starts. But generally we expect that an above average rainfall seasons, particularly ones that are back to back, the probability or likelihood of motion is there," said Matthew Thomas, a research hydrologist with the USGS landslide hazards program.

It can take many cycles of wetting and drying for one of those weaker layers to become a problem.

Take for instance, bentonite clay found throughout the peninsula. According to Lancaster, while the clay is quite strong when it's dry, when it's wet it weakens and expands slightly, allowing for a slight amount of creep. Over time, cracks can grow and fill with water, further jeopardizing the hill structure. Add a whole bunch of weight and steep slopes and things can destabilize over time.

So if you can't predict a slide, what's there to look out for?

Listen for creaks and groans, look for evidence of movement, including broken water pipes and growing cracks.

It’s not always rain that’s responsible. Broken sewer or irrigation lines can also compromise layers and add weight to a hillside and cause it to give out.

What risk does El Niño bring?

El Niño is sometimes linked to wetter winters here in Southern California, which means more opportunity for water to percolate deep underground and destabilize hillsides.

There’s no guarantee that slides will follow a heavy rain year, but it does increase the risk that one will happen, especially in areas that’ve already seen slides, or have active slides ongoing.

According to the preliminary report prepared for the city, there were no earlier slides detected where the July 8 slide occurred in the Rolling Hills Estates area.

What can be done?

Preventing the percolation of water deep into the soil is key. Good surface drainage is an important. Concrete can be used to fill cracks that open up to prevent further infiltration. And in places like Abalone Cove, they've also installed dewatering wells, which actively pump water out.

At the behest of the city of Rolling Hills Estates, the homeowners association began winterization work in November, according to a letter provided by Assistant City Manager Alexa Davis. It includes various measures meant to clear water away from vulnerable parts of the hillside, including temporary drainage, grading and sandbags.

If you’re nervous about your property, you need to be on the lookout for growing cracks and listening for sounds of the earth moving. If your doors have suddenly fallen out of plumb and your windows aren’t opening, you may be facing a catastrophic issue.

If it’s not an emergency, but you're curious about what's going on beneath your home, hire an engineer to look at the geotechnical report relevant to your property.

What do you want to know about fires, earthquakes, climate change or any science-related topics?

Jacob Margolis helps Southern Californians understand the science shaping our imperfect paradise and gets us prepared for what’s next.

The seafloor off the Palos Verdes Peninsula may contain low levels of radioactive materials, according to new research, which also confirmed previous reports that the harmful insecticide DDT is spread across the ocean there at high concentrations.

There is only circumstantial evidence for the cause of the radioactive materials, though nuclear testing and waste disposal are among the potential culprits, researchers said this week. Yet, the now-banned DDT is potentially the bigger ecological threat, researchers said — perhaps even being the reason bald eagles disappeared from Catalina Island for a time.

Those findings were published on Wednesday, Feb. 21, in the journal Environmental Science & Technology. The research that culminated in the journal article represents another step in the evolution of marine scientists’ understanding of the contaminants that litter the seafloor off the Peninsula — a process that began more than a decade ago.

Researchers now have “indirect circumstantial evidence” that low-level radioacting waste was dumped in the Pacific Ocean by the same now-defunct company that disposed of DDT in the Peninsula waters, said David Valentine, one of the article’s authors.

But even with this new evidence, the expanse of DDT “worries me quite a bit more ecologically” than the radioactive materials, Valentine said. Valentine is a professor of microbiology and geochemistry at UC Santa Barbara — and the scientist whose discovery of barrels off the Peninsula, initially thought to contain DDT, launched years of study into ocean contaminants there.

“I think that we have to recognize that, well, it’s disturbing and it’s not good to dump low-level radioactive materials into the ocean,” Valentine said in a phone interview this week. “(But) it’s probably substantially worse to dump large amounts of DDT waste from an ecological effects perspective.”

The greatest harm from DDT, Valentine said, is that it “biomagnifies.”

Biomagnification, according to National Oceanic and Atmospheric Administration, is when toxic chemicals such as DDT get dumped into the ocean and cause health issues in wildlife, from disease to birth defects.

That happens through a simple, yet destructive, process. Toxins that settle on the seafloor end up in the food chain and works their way up. Eventually, according to the NOAA, “higher-level predators — fish, birds and marine mammals — build up greater and more dangerous amounts of toxic materials than animals lower on the food chain.”

“(Biomagnification) can impact a whole host of animals,” Valentine said. “We’re seeing (that) now with California sea lions, with California condors. There’s so much DDT that has been dumped off California, that we’re seeing effects in those animals.”

Valentine and a team of scientists initially discovered more than 60 barrels on the ocean floor in 2011 and 2013 while exploring the Peninsula seafloor with a remotely operated vehicle.

Since that initial discovery, the research has grown and scientific understanding has become more complex.

In 2021, for example, survey researchers from UC San Diego’s Scripps Institution of Oceanography discovered approximately 27,000 barrels on the ocean floor. They, like Valetine, initially thought the barrels potentially contained DDT. The insecticide, which has been banned for years, had been legally dumped by a local company, the now-defunct Montrose Chemical Corporation, for decades.

But in January, Scripps discovered that those barrels were mostly discarded World War II-era military munitions. A whale graveyard was also found.

The Scripps survey mapped 135 square miles of the San Pedro Basin, about halfway between the Palos Verdes Peninsula and Catalina Island. The technology that allows ocean-floor mapping has advanced so much in just a few year that scientists could now distinguish between barrels and munitions.

But just because those barrels did not contain DDT does not mean the insecticide wasn’t present off the Peninsula. Rather, scientists discovered in 2022 that until regulations curtailed the practice, DDT had been directly into the ocean for years.

“Substantial amounts of DDT remain in these sediments, which are largely unaltered after more than 70 years,” according to the Wednesday journal article, titled “Disentangling the History of Deep Ocean Disposal for DDT and other Industrial Waste off Southern California.”

Valentine is a corresponding author of the article. Other scientists from UC Santa Barbara, Oleolytics, LLC, USC’s Earth science department and elsewhere also contributed to the article.

The Environmental Protection Agency, according to the article, discovered 15 offshore dump sites for disposing “radioactive wastes, refinery and oil drilling wastes, chemical wastes, military munitions, filter cakes, and refuse.”

Montrose had legally dumped DDT from 1948 to around 1961, according to the article.

Montrose contracted with California Salvage Company to dispose of the “strong acid waste offshore and discharge it into the ocean” by barge, the article said.

“Located immediately offshore from the Ports of Los Angeles and Long Beach,” the article said, “the San Pedro Basin received substantial input of these wastes leading to high DDT concentrations recorded in select sediment samples.”

Montrose, based near Torrance, built an acid recycling plant, which began the decline of Cal Salvage waste dumping for the chemical company.

“There was no record of ocean disposal of Montrose sulfuric acid wastes after 1961,” the article said, “the same year Cal Salvage’s operation became regulated by a regional water quality board and a formal dumpsite was assigned to them.”

But Cal Salvage, the article said, continued dumping industrial waste for other clients. Montrose reportedly disposed of 1.5 million gallons of other industrial wastes from 1965 to 1972.

Cal Salvage, meanwhile, continued ocean disposal until the mid 1970s when permitting was not allowed, Valentine said.

No samples of the barrels on the seafloor provide evidence of radioactive waste disposal, the article said, but there is circumstantial evidence that such dumped may have occurred — and doing so may not have run afoul of the law.

“The historical record,” the article said, “points to a scenario in which Cal Salvage was potentially able to openly operate as an offshore radioactive waste disposal company without triggering oversight.”

The trail, though, is cold, Valentine said.

“I don’t actually know when, as a corporation, it dissolved,” Valentine said of Cal Salvage, “or how they were even set up.”

But there is evidence in the sediments that the peak of offshore disposal was the mid 1950s. The evidence, though, also includes fallout from nuclear weapons testing.

There was a “low level fallout of certain radioisotopes all over the planet” from when nuclear testing was conducted above ground by the United States and the Soviet Union.

Researchers, Valentine said, compared the peak concentration of DDT and the amount of radioisotopes to determine when the bulk of DDT was dumped. Carbon-14 dating was also a component used in the dating.

“It was a lot of detonations that released these nuclear products directly into the atmosphere,” Valentine said. “And they then spread on winds as small particles until they settled out. And they settled out all over the planet.”

Radioactive waste, though, does not have the same impact on the environment, Valentine said, since there is “no concentrating effect” like with DDT and the isotopes of the radioactive waste “would have decayed away.”

“There was this offshore disposal of the DDT and that remains largely as DDT today,” Valentine said, “and it’s buried down to two inches two and a half inches beneath the seafloor.”

There are also derivatives of DDT that have broken down and can still be found closer to the surface of the seafloor, Valentine said.

DDT has had a significant impact on wildlife, Valentine said — including on the bald eagle.

The bald eagle effectively disappeared from Catalina Island in the 1950s, Valentine said, in large part because of DDT, even though “we don’t have direct evidence for it.”

There was abundant DDT that was “dumped into the surface water, into the ecosystem,” where the bald eagle got its food, he said.

DDT, he said, is “well known for its properties of eggshell thinning.”

The bald eagle has since been reintroduced to the island.

Studies still need to be done on the World War II munitions that were recently found, Valentine said.

“I’m not aware of of anything in them that would have the kind of effects that DDT would,” he said, “but I think it’s still worth looking into.”

That’s why U.S. Sen. Alex Padilla and Rep. Salud Carbajal, along with 20 other California lawmakers, said in a press release this week that they are urging the Office of Management and Budget to include “robust, long-term funding” to research DDT and other harmful chemicals dumped into the ocean, as well as the impact on the Southern California environment, and human and wildlife health.

The late Sen. Dianne Feinstein and Padilla helped secure nearly $12 million over two fiscal years, 2022 and 2023, to help survey Southern California DDT dumpsites, according to the press release.

“While DDT was banned more than 50 years ago, we still have only a murky picture of its potential impacts to human health, national security and ocean ecosystems,” the lawmakers said in the press release. “We encourage the administration to think about the next 50 years, creating a long-term national plan within EPA and NOAA to address this toxic legacy off the coast of our communities.”

Although gray whales, blue whales and humpback whales are commonly spotted off Southern California, orcas are a rare treat.

For a lucky group of whale watchers Monday, a pod of at least 10 of the distinctive black-and-white whales — including two calves — made an appearance off Palos Verdes Peninsula.

Tyler Askari, assistant port captain with Harbor Breeze Cruises, said the tour agency had received reports of possible orcas Monday morning from ferry crews operating between the mainland and Catalina Island. That afternoon, two whale-watching excursions organized by the company spotted the creatures, which were among the first orcas they had recorded in 2023.

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“For our general area, it’s been about two years” since orcas were last sighted, Askari said.

Orcas are found in every ocean in the world, though certain populations stick to certain regions. They’re also known as “killer whales” and, true to their name, were seen by one of the whale-watching excursions targeting a bottlenose dolphin.

“It’s a sight to see,” Askari said, “because you kind of see Mother Nature at work.”

Most of the orcas that come through Southern California waters are “transient” orcas, also known as Bigg’s orcas. Askari said, however, the pod seen Monday was probably Eastern Tropical Pacific orcas and hailed from the coast of Mexico.

Their appearance Monday “was when they were going up the coast,” Askari said, adding that subsequent reports indicated the orcas were headed back south.

Though this pod of orcas may no longer be gracing Southern California waters, from now through May, gray whales can be seen as they cross through on their annual migration from Alaska to mate and calve in the lagoons of Baja California, Mexico. Humpback whales and fin whales are often seen year-round, while blue whales are more common sights during the summer, Askari said.

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If you want to catch sight of whales this season, Point Vicente on Palos Verdes Peninsula is a hot spot for the activity. The L.A. chapter of the American Cetacean Society keeps track of the animals spotted from the Rancho Palos Verdes interpretive center. As of Wednesday, five southbound gray whales had been seen since Dec. 1, as well as a megapod of more than 1,500 dolphins. More information here.

ROLLING HILLS ESTATES, Calif. (AP) — A landslide tore apart luxury homes on Southern California’s Palos Verdes Peninsula on Monday, leaving a confused jumble of collapsed roofs, shattered walls, tilted chimneys and decks dangling over an adjacent canyon.

The slide in the Los Angeles County city of Rolling Hills Estates began Saturday when cracks began appearing in structures and the ground. Twelve homes were red-tagged as unsafe, and residents were given just 20 minutes to evacuate.

The pace of destruction increased through the weekend and into Monday.

“It is moving quickly,” said Janice Hahn, chair of the Los Angeles County Board of Supervisors, who represents the area. “You can actually hear the snap, crackle and pop every minute when you’re there as each home is shifting, is moving.”

It was initially believed that all of the red-tagged homes were sliding, but Assistant City Manager Alexa Davis clarified Monday afternoon that 10 were actively moving. An additional 16 were being monitored but had not required evacuation, Davis said in an email.

The cause of the landslide was not known. But a fissure running among the homes raised suspicion that this past winter’s heavy rains may be involved, Hahn said.

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“We won’t know until a geologist and a soil expert really does a post-op on this and tells us what happened,” Hahn said. “But because of that fissure, the initial thinking is that it was because of the heavy rains that we had last year and all that underground water has caused this. But we don’t know.”

Hahn said many of the displaced residents were unsure whether they were insured for such loss, including one who moved in two months ago after escrow closed. The county assessor was to meet with the residents to tell them they could apply for property tax waivers.

“My heart goes out to these people,” Hahn said. “We gave them 20 minutes Saturday night to evacuate and get their things. Obviously they didn’t get everything.”

Damaging landslides have occurred previously on the Palos Verdes Peninsula, which rises high above the Pacific on the county’s south coast and offers residents spectacular views of the ocean and greater Los Angeles.

A landslide that began in 1956 destroyed 140 homes in the Portuguese Bend area of the city of Rancho Palos Verdes, and earth continues to move there. The slide coincided with construction of a road through the area, which is atop an ancient landslide.

Among other notable earth movements on the peninsula, a 2011 slide severed the blufftop ocean road near White Point in the San Pedro section of Los Angeles several months after engineers began noticing cracks and fenced off the area for study.

Southern California’s complex landscapes contribute to landslides, according to an overview by the U.S. Geological Survey in conjunction with the California Geological Survey.

Some of the many potential factors include earthquakes, steep slopes, sedimentary soil that is not rock hard, and water percolating down into the earth after heavy rains, the report says.

Human-induced landslide factors include construction without proper grading of slopes, alteration of drainage patterns and disturbances of old landslides.

PALOS VERDES, CA — Torrential downpours hit Los Angeles County over the weekend and on Monday, prompting flood warnings as many cities saw nearly non-stop rain.

The rain pummeled Palos Verdes, making way for drier skies ahead for the remainder of the week according to the National Weather Service. Over the last seven days, Rolling Hills got a total of 2.84 inches of rain and Point Vicente got 1.22 inches according to LA Public Works.

So far this season, the Palos Verdes Peninsula has gotten a total of about 7 inches of precipitation beginning on Oct. 1 according to Public Works.

Most of LA County’s coastline saw between one and three inches of rain over the last three days. The San Gabriel Valley saw almost three inches of rain while downtown LA saw 1.69 inches.

The San Gabriel Dam logged the most amount of rainfall in the last three days in LA County according to NWS with 2.48 inches fallen.

This recent storm brought a variety of dramatic weather conditions throughout Southern California, including dramatic flooding in San Diego County which prompted officials to declare an emergency.

Weather forecasters predicted a very wet winter season to come with a stong El Niño pattern, however, precipitation in California so far this season is only at about 66 percent of average levels.

residents will likely see more dramatic rain storms throughout the winter season as forecasters predict a strong El Niño weather pattern to hit the state.

"What happened in the field of meteorology is that everyone wants to label it El Niño — and this is exactly what's going to happen. Or it's La Niña, so this is going to happen," longtime broadcast meteorologist David Murray told Patch.

In most El Niño winters, the Golden State tends to be rainier than usual from January to March. In moderate to strong El Niño winters, we normally see a strong southern jet stream and atmospheric rivers during that period.

So far, rain totals throughout the state are on par with that of the 2015-16 season, which averaged about 57.9 inches, just above the overall 53.9-inch average based on the California Data Exchange Center's eight-station index.

Following the downpour, Los Angeles County beaches were put under a health advisory as high levels of bacteria are expected for at least 72 hours after significant rainfall.

“Bacteria levels can increase significantly during and after rainstorms, as contaminants within the runoff enters the ocean,” according to the LA County Department of Public Health. “Elevated bacteria levels in ocean water may cause illness, especially in children and the elderly.”