Coastal Landslide

Press Contact:  
Patricia Martel, City Manager
(650) 991-8127
Daly City – A New Year’s Day coastal landslide further eroded an ocean facing bluff west of Northridge Drive in Daly City sometime after 1:00 p.m. The same bluff was the scene of a larger landslide in December 2003, when approximately 500,000 cubic yards of sand and soil broke loose and plummeted to the beach. Yesterday’s slide is believed to be less than half the size of the December 2003 slide, involving a total landmass of 180,000 cubic yards. Despite the ominous pile deposited on the beach, there were no injuries or property damage related to the slide.

The latest earth movement was within existing escarpment limits identified in a geotechnical report prepared by Cotton, Shires and Associates in January 2004. Approximately two-thirds of the slide material made its way to the beach, situated roughly a mile and a half south of Thornton Beach. The south flank of the landslide was deepened by approximately 50 feet, exposing up to 80 feet of vertical rock face. However, the landslide zone has not expanded.

Daly City’s engineers have evaluated the latest slide and determined that it does not appear to pose any additional threat to nearby Northridge Park, the residences along Northridge Drive, or the Avalon Canyon storm drain system. Nevertheless, the slide zone remains extremely susceptible to further movement and remains closed to public access.

The City of Daly City has taken steps to gain additional expert advice regarding the geologic issues related to the area. Cotton, Shires & Associates, the firm that did the detailed evaluation after the 2003 landslide, will report on the effect of the January 2007 slide in relation to the predictions and estimates provided back in 2004.