Things to know about a landslide that has destroyed homes in Southern California

Leaders of a Southern California city hit by a destructive landslide are planning to vote on a resolution to declare a local emergency

A landslide is destroying a cluster of hilltop homes in a gated Southern California community and poses a threat to others. Here are some things to know:

WHAT HAPPENED?

Los Angeles County firefighters responding to a report in the city of Rolling Hills Estates on Saturday discovered cracks in buildings and on the ground. Twelve homes on Peartree Lane were red-tagged as unsafe and residents had just 20 minutes to get out.

Ten of the homes began sliding down into a canyon. Walls and decks ripped apart. Neat tile roofs shattered as they pancaked into a jumble. Although two of the red-tagged homes had not slid down as of Tuesday, county Fire Chief Anthony C. Marrone said they did move.

An additional 16 homes were being monitored but residents were allowed to stay.

HOW LONG WILL THE LANDSLIDE CONTINUE?

Los Angeles County Supervisor Janice Hahn, who represents the area, told reporters this week that it’s only a matter of time until the homes on the Palos Verdes Peninsula fall to the bottom of the canyon.

Authorities can only wait.

“We don't know how long that's going to take,” said Marrone. “We don't know how long that these homes are going to continue to move, but at this time it's just a holding pattern that we're in, waiting to see what the final determination is going to be.”

WHAT HAPPENED TO THE RESIDENTS?

Sixteen residents were displaced. The Red Cross offered hotel vouchers, but they stayed with friends and relatives in the area, according to Mayor Britt Huff.

WHAT CAUSED THE LANDSLIDE?

The cause is not known, but an obvious potential suspect is the exceptionally heavy rain that fell on California this past winter. Water percolating down through soil is known to be able to activate a slide months after the last rainfall.

“For these homes that are already gone into the canyon, there is nothing more that we can do for them,” said Hahn. “But we think after it’s all settled, a good geologist and soil expert maybe will give us a clue about how this happened and if there is any way to prevent it from happening in the future on some other hillside.”

The entire community is private, including the streets, so officials said it will be up to the homeowner's association to hire a geologist. Hahn said the county did recommend geologists and that the association's management company is handling that issue.

IS HOMEOWNERS INSURANCE GOING TO COVER THE LOSSES?

Residents were checking whether their homeowners insurance covers landslides, according to Hahn. In the meantime, the county assessor Jeff Prang was brought in to expedite property tax waivers that could result in little or no tax bills.

“Obviously property is valued based on the land and the improvements,” Prang told reporters on Peartree Lane. “These homes behind us, there are no improvements. Those are a total loss. And the land that was beneath them is now going to be a hillside. So when we’re done valuing this property, they will have nominal value.”

AND WHAT ABOUT GOVERNMENT ASSISTANCE?

The Rolling Hills Estates City Council was scheduled to vote Tuesday night on a resolution to proclaim a local emergency due to significant land movement “requiring immediate and ongoing action from the City, first responder agencies, and utility companies.”

The staff report on the resolution said the costs of responding to the incident were unknown because it was still evolving but adoption of the resolution would allow the city to request funds from the state Office of Emergency Services and the Federal Emergency Management Agency.