Rancho Palos Verdes Landslides

[KNS]

As many folks in the area know the Portuguese Bend area (and several other areas on the peninsula) are situated on active landslides which have been (slow) moving for decades.

https://www.latimes.com/california/story/2024-09-05/unprecedented-landslides-have-rancho-palos-verdes-asking-how-much-worse-can-it-get

Recently the movement in some areas has sped up, in some places as much as 10 inches a week. The utilities have shut off gas and electric to some neighborhoods. Some homes are either destroyed or unlivable. At some point in the future some of these homes will simply be unhabitable. Winter rains will most likely exacerbate the situation. How far does the city go to accommodate these residents?

I hope Wayne is nowhere near these areas!

[pwd72s]

Couldn't read the article without subscription to the paper...reminds me of when similar happened in Portland's toney west hills....mcmansions sliding away. Big legal fight among owners, city for allowing permits, insurance companies, builders. Dunno how it all shook out...

[Noah930]

https://www.nbclosangeles.com/news/local/rancho-palos-verdes-landslide-power-electricity/3500984/?os=f&ref=app

Maybe try this article, as an intro to the topic?

I was trying to look for the financial cost thus far for the restoration of utilities over the years. I recall hearing that it amounted to a significant percentage of the annual budget. This has been going on for years (decades), but has really picked up recently. But over the years, the city and utility companies have to repair the roads, power lines, water lines, gas lines, etc.

Gov Newsome declared this a disaster area, freeing up several million dollars of aid. But the above article suggests that maybe $1 billion will be necessary?! The local politician had a quote of "no expense spared"?! What if there is no practical engineering solution to all this? You can't just dig thousands of pilings 500+ feet into the ground to shore up hundreds of acres of sliding hillside. At some point, like those homes on the Big Island by Kiluaea volcano, you just say that Mother Nature (or Pele) wins, and you abandon the neighborhood.

[KNS]

Originally Posted by pwd72s

Couldn't read the article without subscription to the paper...

Apologies for the link - for some reason I don't encounter a pay wall with it (I don't subscribe to the LA Times). Noah's article explains it well.

The above article goes on to mention problems with sewer connections. At some point when you have a group of homes all moving, you might be able to relocate above ground electric and gas lines. But connection to main city sewer lines will eventually be severed.

[look 171]

I am just about finished working on a house about 2.5 miles from there. I watch the road creep weekly toward the ocean. First was the adjustable sewer pipes, then the new roads section was repaved every two to three weeks and we can see it pulling itself apart. This is the area about 1/2 mile east of the old Marineland. We did one of the geology field trip in Palos Verdes peninsula back in college and the slippage has been a known issues for a very long time. Roads that had been swallowed up into the ocean even back then yet they continue to built near by. They know where the slides are so there are no houses or structures built on it but the occasional few built years back. That slide will continue and will eventually effect other areas where there are structures. Oh, it seem these things only happens to rich people with high price homes. There's nothing near that area under 3-4 mil. The owner and I looked for three years there.

[pmax]

[jhynesrockmtn]

I drove to there from WA a few years ago to pick up my son in laws families Mustang from his Grandparents long time home. They were moving Grandma out and getting the house ready to sell. They had lived there for over 60 years. The house was on Sunnyside Ridge Rd. in Rancho Palos Verdes. The little house ended up selling for $1.7 million. Something that might have been $400 to $500k in my area. I couldn't believe the hills in that neighborhood. Figuring out how to get my 20 foot car hauler down her road and back up was a big challenge. I ended up overheating my trans trying to back out of there with the car loaded :-)

[3rd_gear_Ted]

The original survey maps and GPS coordinates are totally useless.
About a 12" slide down and west is happening every year.
The root landslide is 345 feet below the surface.
Some of the prettiest real estate in the state and its becoming worthless.

[gacook]

Fascinating. We in Arizona are still awaiting the big one. (tasteless, I know...sorry)

[A930Rocket]

Why is the town/state/utilities helping these folks, when they built in an area known for landslides but people who build in a flood zone are SOL?

[KNS]

Originally Posted by 3rd_gear_Ted

The original survey maps and GPS coordinates are totally useless.
About a 12" slide down and west is happening every year.
The root landslide is 345 feet below the surface.
Some of the prettiest real estate in the state and its becoming worthless.

I saw an interesting Palos Verdes article about how a property owner owns the land over a geographical spot on the earth. If your home slowly slides downhill over the course of 20 years, your home is no longer sitting on those coordinates. Your actual property may now be a barren plot of land (or your neighbor's house maybe sitting on it) while your home is technically somewhere else.

[3rd_gear_Ted]

Originally Posted by A930Rocket

Why is the town/state/utilities helping these folks, when they built in an area known for landslides but people who build in a flood zone are SOL?

If you saw how beautiful the area is, I can see why some took the risk.

[ckissick]

We learned about this area in in about 1980 in one of my geology classes at UCSB. So, yes, it's long been known as an active landslide. I looked at historic aerial photos and the neighborhood currently being affected was built between 1954 and 1963. In 1954 there were dozens of small houses or possibly manufactured homes to the west, on or very close to the beach. In 1963 they were all gone.

So while they were being removed, a whole neighborhood was built less than 2000 feet away. But those houses in the affected neighborhood have lasted about 60 years. Most are probably in good condition. Utilities are a big problem, though.

[pmax]

Originally Posted by KNS

As many folks in the area know the Portuguese Bend area (and several other areas on the peninsula) are situated on active landslides which have been (slow) moving for decades.

https://www.latimes.com/california/story/2024-09-05/unprecedented-landslides-have-rancho-palos-verdes-asking-how-much-worse-can-it-get

Recently the movement in some areas has sped up, in some places as much as 10 inches a week. The utilities have shut off gas and electric to some neighborhoods. Some homes are either destroyed or unlivable. At some point in the future some of these homes will simply be unhabitable. Winter rains will most likely exacerbate the situation. How far does the city go to accommodate these residents?

I hope Wayne is nowhere near these areas!

[look 171]

Originally Posted by pmax

That is directly on the other side of the hill, stable there for now and I think it has been. Plenty of homes or buildings on that same side.