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Landslides raise concern, warning for coastal blufftop living

Beachfront homes line the Southern California coastline and bluffs, offering multi-million dollar views out to the blue Pacific, where the sun dips daily down into the ocean’s colorful horizon.

But that access to the beach’s beauty comes at a price: the risk of water, whether it’s the unpredictable sea battering the shore and any properties in its way or, like this winter season, the relentless rains that have been causing havoc up and down the state.

Much attention in recent years has been on beachfront homes in danger of flooding with big swells and high tides, especially as sea-level rise is expected to exacerbate the threat of the ocean overtaking coastal areas. But this wet winter, the spotlight has shifted to properties atop hillsides made vulnerable by saturation.



In Newport Beach, a home atop a cliff overlooking the Back Bay was demolished this week after its patio slid down a slope – two more remain yellow-tagged out of concern. Four apartment buildings on a bluff in San Clemente had to be evacuated on March 15 after an earth shaking landslide dropped decks down a hillside and onto a beach path below.

They were deemed so unstable, renters had only a few hours to grab their belongings before they were red-tagged. Another landslide in Dana Point that same day, following a heavy rainstorm that battered through the night, shut down Coast Highway for the second time this winter season.

A 200-feet section of hillside in Palos Verdes Estates collapsed in December, causing a stretch of beach to close and some homes to be evacuated. The city hopes a $33 million project will help secure the bluff, though the large-scale project needs grant money from the Federal Emergency Management Agency. A public hearing for that project is coming up March 21.

County, state and federal agencies have declared official state of emergencies, hoping to give some relief to the communities, residents and homeowners. Orange County was added this week, but Los Angeles County had already been included in state and federal responses.

The damage, especially as more rain is expected in coming days, has people thinking about the vulnerability and realities of coastal living.

“These are really, really challenging issues because a lot of development in Southern California is on bluffs and cliffs,” California Coastal Commission Chair Donne Brownsey said. The state agency is tasked with regulating planning and development of the coast.

For the building owners in this week’s San Clemente landslide, an uncertain future faces them. Will the buildings need to be knocked down? Can they add a seawall to support the structure?

For the renters, it likely means finding a new place to call home. And what’s to become of their belongings, locked inside the unstable homes?

For the communities, there are now issues of beach access – short-term, fencing has been installed to keep people off nearby stairs down to the beach and that section of popular coastal trail is closed to use, possibly for months.  

San Clemente resident Dave Cinquini, 37, walked the beach trail with his golden retriever, Harvey, one of many curious people who stopped to look or pointed cellphones through the chain-link fence blocking path access.

“I can’t really say I’m really surprised,” he said, noting the several other buildings along the same bluff that almost appear teetering on the edge. “What’s across the street today will be beachfront, eventually.”

He feels for the renters, he said. While it’s a beachfront community, this is one of the most affordable neighborhoods along the coast.

“People are going to be displaced,” he said. “Now they are going to have to move and they are jumping into the most expensive rental market of all time.”

Further south, on the other side of town, an ancient landslide was triggered at Cyprus Shores two years ago and again last September, resulting in two homes on top of the bluff to be red-tagged and two others yellow-tagged. The Orange County Transit Authority is nearly finished with a months-long, $13 million repair to train tracks below the homes and securing in the bluff, with some passenger rail service still halted.

Mayor Chris Duncan said a large-scale analysis to identify “sensitive spots” along the ocean-front bluff, which stretches the length of the coastal town, is needed. It’s unclear what would happen if cliff-side homes were deemed in danger of slipping in such a mass survey, but likely the California Coastal Commission would have a say in what repairs or precautions would need to be done, he said.

“From our perspective, we just want to make sure people are safe. We need to make sure a home doesn’t come down here and we didn’t have the intel about it ahead of time,” Duncan said. “Further down, you see more exposed areas where there’s already a patio hanging down into an empty space. Maybe that’s the next spot – we just don’t know.”

Already, the city has contracted with a coastal engineering firm, Moffatt & Nichol, to study sand erosion and assess beach sections vulnerable to the ocean. Since bluffs contribute to the sand supply, an analysis of the cliffs may be part of that, and if it’s not, it should be, Duncan said.

“There hasn’t been this situation, because it’s been so dry,” he said. “It’s happened in the past, but not for a long time.”

The state Coastal Commission gives grants to coastal communities wanting to be proactive in planning, said Brownsey.

“As sea-level rise escalates and as climate change produces more dramatic weather events, this just really underscores how important it is for these coastal communities to do vulnerability assessments and adaptation plans, so they can get ahead of some of these challenges,” she said. “To not act will simply cause a lot of heartache to those who live in those communities.”

It’s smart for coastal communities to start looking at vulnerable properties, so actions can be taken before emergency situations occur, she said.

“A lot of people think they have decades before they are going to have to address these issues,” she said. “While those blufftop homes are desirable, they are also the ones most at risk.”

The relentless rain this season has exasperated the troubles.

Sometimes, a bit of water is a good thing. Compare it, say, to adding a bit of moisture to a sandcastle so it sticks together.

But dump too much water, and the sand collapses.

“The sand castle analogy applies there,” said Nate Onderdonk, professor in the Department of Earth Science for Cal State Long Beach, of this week’s landslide in San Clemente. “Essentially, the water can destabilize in two ways. One, it adds weight to the slope as it seeps in and gets trapped in, so it adds weight. In the other way, it can lubricate any (areas) of weakness in the rock.”

The stability of any cliff or slope or hillside is really a function of three things: the underlying rock type, how steep the slope is and the amount of water, Onderdonk said.

“The only thing that’s really varying here is the amount of water,” he said. “Whenever they built those buildings, they inherently destabilized the slope a little bit. Any added weight, man made or water, can make the slope less stable and cause it to fail somehow.”

Onderdonk said cliffs are in constant erosion and have been, far before structures were put on top of the bluffs.

“The rain triggered this specific slide, but it’s not out of the ordinary at all, it’s sort of expected,” he said. “Obviously, putting a house on the cliff, you get a great view, but I think everybody or anybody that buys a home near the cliff, there’s a geological lifetime of that property. It’s going to erode eventually.”

There have been many past landslides in the area, Onderdonk said, noting an area just to the north in Dana Point where “fake rock wall” was put in back in the ’90s to stabilize a bluff.

In that 1993 landslide, five ocean-view homes came crashing down, along with 44,000 tons of dirt that blocked the highway. Dana Point rebuilt the collapsed bluff and applied a surface to make it look like a natural bluff.

“There’s different ways they can try and slow the erosion down. And it would probably work over the normal human lifetime. But over the long term, it’s going to fail,” Onderdonk said.

It’s not just the coastal properties that should be concerned. Half of San Clemente is built on old landslides, he said, even areas on the inland side of the 5 Freeway.

“That’s why you have so much open space still,” he said. “Because it’s unstable to build here.”

Brownsey said much more is known today than decades ago. And communities have to ask the question of how might solutions affect public spaces, such as beaches.

A retaining wall protects six homes the in the 2800 block of La Ventana in San Clemente, CA, on Friday, March 17, 2023. The houses were rebuilt after a landslide in 1993 which buried Pacific Coast Highway and the Santa Fe railroad tracks beneath 44,000 tons of dirt. (Photo by Jeff Gritchen, Orange County Register/SCNG)
A retaining wall protects six homes the in the 2800 block of La Ventana in San Clemente, CA, on Friday, March 17, 2023. The houses were rebuilt after a landslide in 1993 which buried Pacific Coast Highway and the Santa Fe railroad tracks beneath 44,000 tons of dirt. (Photo by Jeff Gritchen, Orange County Register/SCNG)

“Your beaches will start to disappear because you’re interfering in the natural process,” she said about some solutions, such as installing sea walls or big boulders to protect against waves.

For the building owners facing the realities of the landslide in San Clemente, they will have to do an assessment to determine if the bluff is even stable enough to put in a protective structure, she said. If the bluff is unstable, the city may need to look at removing those structures.



Most of the effort in recent days has been on displaced renters, but Duncan said the city and county will be connecting with property owners who may need help. The county has a tax-deferred program for red-tagged properties and other financial assistance. But, with most insurance companies not covering landslides, they may be facing a huge loss.

“The property owners will potentially take the biggest hit,” Duncan said. “There’s resources, but but they may be small compared to the loss they will incur.”

Even blufftop owners who don’t have issues today, but worry about the future, may opt to move their building back or remove decking in jeopardy, Brownsey said. Maybe they’ll remove pools or spas. Perhaps they will need a seawall.

But any plan will come with a lot of questions from the Coastal Commission.

“Our staff goes into really deep detail in terms of whether or not this is a property that can be eligible for seawalls. What’s the risk and what kind, what would be the impact on the ecosystem and the beach and would it interfere with public access,” she said.

Long-term, the solutions that might be needed to protect the homes can also threaten beach access for the general public. Seawalls can prevent natural erosion that typically replenishes beaches.

“These are incredibly difficult decisions,” Brownsey said, adding these situations will continue to arise, especially as climate change and sea rise become more apparent.

“Who would have thought we would have 11 atmospheric storms and Southern California would get so much rain. It’s so unusual,” she said. “I think that sounding the alarm for the future is no longer appropriate. Climate change is no longer our future, it is today.”

Source: Orange County Register

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