Caltrans crews are racing to shore up a battered stretch of Pacific Coast Highway north of Sycamore Canyon Road, dumping multi-ton boulders along the shoreline after a recent Southern California storm washed out part of the roadway. The work, aimed at getting the highway ready before an El Niño winter arrives, is happening right along the edge of Thornhill Broome Beach in Point Mugu State Park.
According to a post from Caltrans HQ
, which retweeted Caltrans District 7's announcement Friday, crews are constructing Rock Slope Protection on the shoreline along State Route 1 north of Sycamore Canyon Road after a section of the highway washed out during the region's most recent storm. The emergency work comes amid high surf and extreme ocean swells that forced Caltrans to close an ocean-side lane of PCH near the same beach.
Laguna Beach Patch
reported crews installing protective mesh and placing boulders along the coast to prevent further erosion.
A Narrow Highway Squeezed Between Mountains and Ocean
The stretch of PCH under repair runs alongside Thornhill Broome Campground, and Point Mugu State Park offers camping facilities, according to California State Parks. Point Mugu State Park spans 14,000 acres and five miles of ocean shoreline in the western Santa Monica Mountains, and that proximity means high surf can spill directly onto the roadway shoulder rather than simply lapping at a beach.
Caltrans District 7, which oversees highway infrastructure across Los Angeles and Ventura counties, has repeatedly had to intervene along this exact corridor. In February 2024, Caltrans instituted nightly 13-hour closures along a six-mile section of PCH between Sycamore Canyon Road and Las Posas Road after storm-driven surf had eroded shoulder berms and rock slope protection, according to Malibu Patch's prior reporting.
Coastal Protection Along PCH
Rock slope protection is an approach Caltrans uses along the coast. A USDA Forest Service research compilation on California bank and shore rock slope protection identifies Caltrans' Rock Slope Protection standards. It's the same basic defense Caltrans used in September 2021, when it launched a $51 million coastal slope restoration project nearby, building two retaining walls to shore up bluffs undermined by ocean surf — a project Hoodline detailed in earlier coverage of Mugu Rock crashes.
Caltrans has used different forms of coastal protection nearby. The current work uses rock slope protection, while a 2021 coastal slope restoration project involved two retaining walls.
Preparing for Winter Weather
The current push to armor the shoreline comes amid forecasts of El Niño storms. The rock work at Thornhill Broome is part of efforts to protect vulnerable coastal roads before the season's heaviest weather arrives.
Hoodline reported Thursday that a woman died after a wave swept her off beach rocks during the same bout of high surf that battered Thornhill Broome, in a drowning near Sycamore Canyon, underscoring the danger along this narrow stretch of coastline.
