El Niño threatens homes built on California hillsides

LOS ANGELES – Anytime heavy rains douse this region, many eyes are cast upwards to the multi-million dollar homes precariously perched on hillsides towering over Hollywood and Malibu.

The prime real estate scattered throughout the Santa Monica Mountains above the city are at the most risk when heavy El Niño storms create mudslides or earthquakes rattle the ground.

“California is a landslide-ridden state,” said Alan Kropp, a geotechnical engineer founder of the consulting firm of Alan Kropp & Associates Inc. in Berkeley, California. “Long before people were settling and building here, there were landslides.”

But – in an often status-obsessed city - the threat of homes toppling down the hills has always been trumped by the desire to live high above the crowded streets and has become the signature address for the wealthy.

“The higher the elevation in Los Angeles, the richer you are,” said Robert Lang, urban affairs professor and director of Brookings Mountain West at the University of Nevada Las Vegas. “First off, they’re secluded and there’s a lot of privacy. You’re in this very dense, second-largest metropolis (after New York) and meanwhile, by just driving up a hill, you feel like you’re in a semi-rural private space and lifted out of the valley and smog.”

It’s the same reason, he says, that affluent New Yorkers live in penthouses and on the highest floors of residential skyscrapers, far above the madding crowd.

But in California, the push-pull between human nature and Mother Nature can be costly and those with big bank accounts are willing to pay for it. But should they even be living there?

The trend that began in the post-World War II construction boom can’t be reversed, according to experts. But what has changed is the engineering technology that can make even the most hazardous hillside location if not totally safe, at least safer.

“Now, in general, you can build in most places with geologic and engineering but there are some that are virtually impossible, it doesn’t matter how much money you have,” Kropp said. “The unfortunate thing is that there are more recently constructed facilities that weren’t done as well as they should’ve been.”

In 1983, 250 Malibu homes collapsed, cracked or slipped off their foundations in the Big Rock Mesa landslide, one of the worst in state history. A tentative settlement was reached more than four years later with the county, state and insurance companies that paid homeowners $97 million in damages or about $200,000 for each homeowner.

“We have the technology to be able to build in those areas, sure, but you do calculate some risk in that,” Lang said. “What’s the social responsibility for sharing an insurance risk with a person who’s rich and lives on a risky hillside. It’s within their right as a land purchaser to build but the issue is more public responsibility of the public pool of insurance.”

In a sense, he said, everybody ends up bailing out the rich.

The technology that has minimized the risk of erecting houses on hillsides is LIDAR (Light Detection And Ranging), which eliminates vegetation from aerial and ground photographs. “You see what the bare earth looks like and then you can really see what’s going on,” Kropp said, including cracks and land shift patterns.

The state has also released new maps that pinpoint areas where earthquake-induced landslides could occur. Engineers and geologists may require remedial grading, subsurface drainage and deep foundations to hold the hill back. 

But there is a problem. New technology and mapping is worthless for homes built decades ago.

“It’s an unfortunate situation that there are lots of houses existing on weak ground … and some, in each El Niño, will give way,” Kropp said.

That’s a concern for owners of new homes built next to an older home.

“That guy just uphill of you doesn’t look too good and could come down on top of you,” Kropp said, which requires “defensive design” for new construction.

Homeowners should not be lulled into thinking that just because some homes are still standing after decades of earthquakes and torrential rains, they are safe.

“There are mud flows, more liquid types of landslides that move quickly and can be very destructive,” Kropp said. “But later in the year, we’ll get more deeply-seated mudslides that move inches or feet a day and that’s even more devastating because it moves more land and it’s more difficult to stop.”

But wealthy homeowners are deaf and blind to the risks when they find a secluded hillside property and see the breathtaking views and hear birds chirping. And that’s what money can buy.

“It can be five to 10 times more expensive now to build on an unstable lot than on a stable lot,” Kropp said.

Larry Gross, executive director of the Coalition for Economic Survival, a Los Angeles non-profit that advocates for low-income communities, is more concerned with the impact of El Niño on the homeless and low-income tenants who may be dealing with leaky ceilings.

“Clearly, the (hillside homeowners) have more resources to respond to this and I would imagine more political clout to get a response from the city,” he said.