A row of Silverado Canyon homes where a falling boulder killed a 16-year-old girl last month are at "high risk" for more rock slides, according to a geologists' report released Friday.
Another slide "could occur at any time," says the report, and could damage homes unharmed by the Feb. 20 slide.
The report, prepared by Goffman, McCormick & Urban Inc. for Orange County's Planning and Development Services Department, urges property owners to hire geologists to recommend ways to prevent rockslides and to construct barriers to protect their homes when rocks do fall.
The report's recommendations include removing loose boulders that sit above the two damaged homes; building protective walls, nets, fences and roofs to withstand rock impacts; and removing rock outcrops, which are likely sources for falling boulders.
If the two properties that were severely damaged during the February storm are demolished, the report recommended building a "rock-debris containment area" to prevent neighboring homes from being damaged in possible future slides.
Timothy S. Neely, director of the county Planning and Development Services, said the report showed that the area above the two damaged homes remains at a greater risk because of loose boulders perched above. Those risks would need to be addressed if the property owners decide to rebuild.
Neely said the report showed that the two undamaged homes "still have significant geological risks" but that they are not in greater danger because of the February slide. He said he planned to allow those homeowners to move back in after they review the report and sign a waiver releasing the county from liability.
During February's heavy rains, boulders tumbled down the steep hillside above Silverado Canyon Road, killing Caitlin Oto, an El Modena High School student, and severely damaging two properties. Those properties were also damaged in a 2001 slide.
Two additional homes flanking the damaged ones were "yellow-tagged," restricting owners' access pending further study. It was those homes that the report said could be hit by boulders, even though they are not directly under the ravine the two damaged homes are under.