As Houses Slide, Who Slipped Up?

From his home atop a 67-foot slope in Mission Viejo, Steve Schade enjoyed a sweeping view of the suburbs below. Miles away in Anaheim, panoramic vantages of north Orange County from an even bigger hill drew the Kabiri family to build their $2.5-million dream home above the Santa Ana Canyon.

But the houses started to slide in January following heavy rains that saturated hillsides, leaving homeowners from Oceanside to Culver City watching helplessly as their homes teetered and buckled.

The Anaheim dream home was finally knocked down and two neighboring homes are sliding down the hill. In Mission Viejo, meanwhile, a home below Schade’s has snapped as the hill above creeps closer to it.

Experts say it is nearly impossible to predict a slide, and nearly as difficult to determine who -- homeowners, builders, geologists or cities -- should be held responsible when one occurs. Still, homeowners often turn to the courts to sort it all out.

“People pay premiums to be on hillsides. The views are great ... but hey, it’s no fun when the house falls down,” said Paul Hegness, an attorney who has represented landslide victims.

In Anaheim, Ali Kabiri’s 5,000-square-foot home began shifting in January and was declared uninhabitable. Houses on either side of Kabiri’s began sliding soon after.

An unfinished structure to the north was red-tagged after it began to crack, and a third home on Ramsgate Drive -- a street of mansions in a gated community -- was red-tagged Feb. 5 after the slide accelerated.

Crews hired by the city demolished Kabiri’s home, hoping workers could shore up the foundation of the nearby third house. But this week city officials said that at least half of the house would probably be lost.

Meanwhile, debate over what caused the landslide boils. City geologists said that fill dirt brought in years ago was the culprit, while a geologist hired by the Kabiris said that an ancient landslide reactivated by last month’s record deluge was to blame.

Kabiri’s attorney said he was investigating why previous soil experts didn’t identify the ancient slide.

Hegness, who is not representing affected homeowners in Anaheim or Mission Viejo, said blaming geologists for missing an ancient slide will be a tough sale in the courtroom.

Although the state publishes landslide maps identifying historical landslide areas, “they’re never complete,” he said. “We just don’t know what’s down there.” Hegness said he wouldn’t be surprised if a dozen or so contributing factors were ultimately identified. Everything from gopher holes to sprinklers left on during the rains, or concrete patios put in by a homeowner could be a factor.

In Mission Viejo, Schade’s backyard started sagging when the steep hillside below his house began to give way.

“I didn’t think it was that big of a hill -- good-sized, but I never realized it could do what it’s doing,” Schade said.

The hillside, which has been moving about an inch a day for three weeks, has smashed planters and caused pool decks to buckle below his house. The six affected homes -- Schade’s at the top of the hill, and five down below -- have been yellow-tagged. Red-tagged homes are uninhabitable; yellow-tagged homes can be entered during the day.

Contractors hired by the city last week placed plastic tarps over the hillside to keep it dry as crews wait for a break in the weather to finish an emergency fix: transferring soil from the top of the slope to the bottom to stop the sliding.

“We never ever, ever thought of it sliding like this,” Schade said. “You don’t understand how devastating this is until its happening to yourself.”

Typically, people who want to build on a hillside hire geologists to study the slopes and offer ways to anchor their foundations. Most soil testing involves boring a hole to look for unstable soils.

Geologists can predict how different soils will react under the weight of a building, but drilling holes doesn’t always yield the entire history of a hill. “Drilling a hole in the ground is like shining a flashlight into a dark room -- you can only see what’s in the beam of the flashlight,” said Shell Medall, an engineering geologist with Associated Soils Engineering. “If you see an empty room, you might assume the rest of it’s empty, but it may not be.”

To guard against potential slides, one of the most common methods homeowners use to stabilize their foundations are caissons -- concrete support pilings sunk into bedrock, said Greg Axten, a geo-technical engineer for the Kabiris.

Caissons can cost $10,000 to $15,000 apiece, depending on how deep they go. The number of caissons per home depends on the slope’s grade and the size of the structure.

None of the three homes sliding in Anaheim Hills were built on caissons, despite soil reports by previous developers recommending them. But for all the soil testing and expensive engineering, the most common cause of landslides -- water -- is often out of a homeowner’s control.

Although conventional wisdom about hillside living calls for plants and shrubs to prevent erosion, experts say that over-watering a slope can be just as dangerous as leaving it bare.

Most modern slides occur along older fissures reactivated by wet weather or irrigation.

“I would think there will probably be a few more [slides] that haven’t started to move but probably will if it continues to rain,” said Kevin Schmidt, a geologist with the U.S. Geological Survey.

But experts said that the incidence of slope failure is relatively small, considering how much building has occurred in the county.

“If all of Anaheim Hills were subject to landslides, it would be Anaheim flats,” Medall said. “Obviously the earth wants to erode everything and bring it down to a flat form, but we’re resisting that with homes.”