Evacuation order lifted at La Conchita, but officials warn area is still vulnerable to landslides
After one of the heaviest storms in more than a decade, authorities lifted an evacuation order for La Conchita earlier this week — allowing residents to return home to the seaside hamlet north of Ventura but warning the hillside remained vulnerable.
The community of around 300 sits below an unstable hillside, one that gave way in 1995 and again in 2005 when a landslide killed 10 and buried homes with no warning.
Authorities have declared it a geological hazard zone. Public safety departments say they have no surefire way to predict if or when the hillside could fail because of the complex nature of the hazards.
“We do everything in our power to try to determine potential risk up there," said Patrick Maynard, director of the Ventura County Sheriff's Office of Emergency Services. "But there's really no way of knowing when something is going to happen."
The county looks at historical triggers and the area recently reached one of those thresholds. When forecasts projected rainfall rivaling what triggered past incidents, authorities knocked on doors last weekend and talked to residents about the potential danger.
On Monday, as rain pummeled the region, dirt on the hillside moved again and an evacuation was ordered.
An unstable hillside
The rain caused debris from an older landslide to fall about 150 feet. But the mud stopped before reaching the homes, said county Geologist Jim O’Tousa. While shallow, that marked the first known slide since 2005, not including a smaller slide in 2010, he said.
After the rain stopped Tuesday, geologists again analyzed the hillside and found no imminent signs of significant failure. At 6 p.m., the evacuation order was lifted. But, county officials said, that decision should not be construed that the area was deemed safe.
O’Tousa said the community is vulnerable to landslides due to an earthquake fault, the composition of the hillside and its height and steepness. Water goes through the top sandy layer rather easily but not the rock beneath it, creating pressure on the hillside, the geologist said. The height and steepness increase the chance that the mud will fall very fast. Added to that is the unpredictability of rainfall.
“I certainly can’t predict when things are going to fail,” he said.
County officials declared the community a geological hazard area after the 1995 slide because of those issues and the difficulty of predicting how the hillside will behave, O’Tousa said.
They established three triggers indicating heightened risk, and one was reached with the recent storm ending Tuesday when a little over 8 inches of rain fell in 14 days. That essentially matches the two-week period before the 2005 landslide when 8 inches of rain fell.
The two other triggers: One or more inches of rainfall per hour, and 15 inches within 30 days.
The 'greatest place' to live
Mike Bell purchased a home in La Conchita around 40 years ago and calls it "the greatest place in the world to live." The community, just 10 blocks wide and a short drive to Carpinteria or Ventura, has beautiful ocean views and neighbors who check on one another in good times and bad.
"I live below a hill; I always have concerns," Bell said. "But I also have a computer set up in my office. I can go sit down at my computer and, in five minutes, tell you how we're doing rain-wise."
Some places in town he would not feel comfortable at times, he said. But he feels pretty safe in his home, which is closer to the freeway and farther from the hillside.
Bell cleared mud from a couple of streets atop the community's tractor on Wednesday. A few blocks away, Andrew Wolfinger, who recently moved to La Conchita, shoveled sand into bags for a neighbor. He left home to pick up his wife from work about 15 minutes before the evacuation order was issued on Monday.
"I had packed some stuff in the car already, so we stayed in a hotel," Wolfinger said.
On his street, Dennis Hall and many of his neighbors stayed despite the evacuation order, he said. They watched for rocks or muddy water coming down and kept in touch throughout the night.
"I said to my neighbor, if things get nasty, I’m coming knocking. We’re going to go out together," Hall said.
More rain on the way
The forecast shows a couple of storms headed this way over the next few days.
The first is expected to reach Ventura County Saturday and could bring around an inch of rain in most areas of the county. On Monday, a half-inch to an inch of rainfall is expected, said Ryan Kittell, a meteorologist with the National Weather Service in Oxnard.
Authorities have advised La Conchita residents that the hillside is still susceptible to landslides or debris flows. They should monitor conditions, report any signs of additional failures, and should not wait for local authorities to issue evacuation warnings or orders before leaving the area.
My wife won't sleep well, Bell said of the upcoming rain. He will be on his computer monitoring the storm.
"I think we'll be okay. If I didn’t think we’d be okay, I'd be out of town," he said. "We don't want to cry wolf. But we don't want to not be prepared either. So you have just got to stay on top of it."
Cheri Carlson covers the environment and county government for the Ventura County Star. Reach her at cheri.carlson@vcstar.com or 805-437-0260.
This article originally appeared on Ventura County Star: Storm causes shallow landslide at La Conchita, California
