Caltrans begins top‑down removal at Topanga landslide, says reopening date still uncertain

Caltrans on Tuesday described a top‑down excavation plan to remove loose material from the Topanga Canyon landslide and said crews are working around the clock to clear debris and protect sensitive habitat.

"We do have a geotechnical report, and the strategy for reopening the roadway is to remove the loose slide materials from the top to the bottom," Caltrans District staff Lauren said, outlining an access‑road approach that began last week so heavy equipment can reach the top of the slide and work down the slope.

Nina Choi, a Caltrans geotechnical presenter, told residents the slide is active and likely translational in character. "What we found was it's an active landslide with rock or debris. There were several boulders that had also fallen ... 6 to 8 feet in diameter," she said, describing visible groundwater and the need for daily monitoring while crews map and model the slope for a mitigation plan.

Caltrans said it has sent its geotechnical recommendations to Caltrans Maintenance and Construction and to two external reviewers — LA County Public Works and the California Geological Survey — for peer review. "We are performing analysis and we developed our recommendation for the repair mitigation of the slide," Choi said.

Officials stressed public safety and environmental protections. Danielle Lefur, senior environmental scientist with California State Parks, said Parks helped select access routes and required erosion controls. "Our first concern was making sure that sediment didn't end up in the creek because it's critical habitat for the steelhead trout," Lefur said; she added that bird surveys were completed before heavy work began and that a restoration plan will follow operations.

Caltrans construction staff said contractors are working 24/7 to excavate the access road and haul materials to nearby destinations, with night hauling planned to reduce daytime congestion. The agency told residents to stay out of the work zone: crews must stop work whenever people enter the area, causing cascading delays.

On funding and the emergency declaration, Caltrans cautioned that the state declaration primarily allows the agency to seek federal reimbursement, not to bypass technical steps. "This is a mechanism for seeking reimbursement from the federal government. It is not to accelerate the project," Lauren said. Separately she added the department has state emergency funds and a contractor on board.

Caltrans acknowledged it could not yet provide a firm reopening date. Officials said the size and character of excavation will depend on what crews find once they begin more extensive grading and any subsurface borings, and they will post substantive updates on a new project page on the Caltrans District 7 website and in twice‑weekly emails. Caltrans also said it is exploring installing a live camera at the site to increase transparency.

What happens next: Caltrans will continue top‑down grading and hauling, complete peer reviews with LA County Public Works and the California Geological Survey, and decide whether additional subsurface investigation is required. The agency said it will post schedule and safety decisions on the project website and through biweekly updates.