SR-27 in Topanga Canyon Opened June 2, Months Ahead of Schedule
ADVISORY: Continuing emergency repairs will require one-lane closure with flaggers directing alternating traffic during off-peak hours at postmile 1.8 on SR-27. Schedule is to be determined. Check Quickmap.dot.ca.gov for real-time road conditions.
State Route 27 Landslide Recovery Plan
Overview
The California Department of Transportation (Caltrans) and emergency contractors cleared a massive landslide that closed State Route 27 (Topanga Canyon Boulevard) at postmile 1.8 months ahead of schedule by working 24/7 through May. Caltrans completed a geotechnical report that determined the safest method for clearing the landslide from the top down. After building an access road to the top of the steep slope, a spider excavator pushed down landslide material to the roadway as a long-reach excavator clawed away at the face of the hillside from the bottom. Trucks hauled away the dirt, rocks and boulders overnight. The landslide was not as deep as initially thought, which helped speed up the clearing process.
The landslide occurred on March 9, 2024, after a series of atmospheric river storms dropped an unprecedented amount of rain that saturated hillsides throughout Los Angeles and Ventura counties. Caltrans immediately instituted a full closure of SR-27 from Grand View Drive to Pacific Coast Highway (State Route 1).
The Department initially estimated the roadway would reopen by fall 2024, depending on weather and other conditions beyond the control of Caltrans.
Updates have been provided on a regular basis with community meetings involving the Topanga Town Council, social media posts and e-mail advisories at least twice a week.
Project Impact
This section of State Route 27 is used by more than 14,000 vehicles a day, on average.
Caltrans installed temporary signals at PCH and Tuna Canyon Road, a one-way southbound county road, so motorists could safely make a left turn to southbound PCH. Tuna Canyon temporarily served as the primary southbound route to PCH. The signals are scheduled to be removed the night of June 5 because they are no longer needed with the opening of SR-27.
Frequently Asked Questions (FAQ) as of May 13, 2024
Landslide on State Route 27 - "Not your typical slide"
Question: "What is the history of this area?"
Answer: Two winters of atmospheric river storms saturated hillsides in Topanga Canyon, which historically are prone to landslides but not usually this large. A landslide adjacent to the current one occurred in the 1940s. This year's landslide is twice as large. The soil had to dry out to stabilize the hillside. Little to no movement was finally detected in late April, a sign that it was safe to begin clearance work. A rock fence made up of a cyclone fence attached atop k-rails was built opposite of the landslide to protect the environmentally sensitive Topanga Creek, which runs parallel to the southbound lane of State Route 27.
Q: "Couldn't one lane have been opened for motorists?"
A: The landslide covered both the northbound and southbound lanes in a tight section of the mountain roadway. Heavy equipment, such as loaders and excavators, were operating in the area to clear the landslide. Caltrans' priority is safety for the public and workers. There is limited room in the work zone. Providing one-lane access would have been unsafe and delayed work.
Q: "Why didn't Caltrans move faster to start this process?"
A: Actually, Caltrans started this complex investigation process immediately after the slide occurred. Caltrans secured the area and monitored the slide for further movement. Caltrans immediately began developing a plan of action for reopening State Route 27 as quickly as possible in cooperation with California State Parks, California Coastal Commission, Los Angeles County agencies and Southern California Edison, which has power lines along the roadway. Also, Caltrans immediately started the geotechnical investigation of the slide area. Caltrans assembled teams of experts in design, construction, and emergency operations for an all-hands-on-deck response to this event.
Q: "How can I stay informed?"
A: Caltrans has a designated email, Topanga@dot.ca.gov, where residents can submit questions or suggestions.
Q: "What happens in the event of a canyon fire and residents need to evacuate?"
A: Los Angeles County Fire Department (LACFD), Los Angeles County Sheriff, CHP and Caltrans coordinate possible evacuation routes depending on the situation. LACFD typically takes command during incidents and coordinates the response from first responders or external agencies. Historically speaking, Caltrans and CHP will close access into the Canyon from PCH and the San Fernando Valley to allow residents to evacuate. Caltrans at times has assisted LACFD with watering trucks and equipment. We recommend reaching out to LACFD for additional questions on evacuations.
Caltrans was able to open the roadway well before fire season. The Department appreciates the support and cooperation of its partner agencies, including California State Parks and Los Angeles County Public Works Department.
Q: "Are there any issues with funding for this emergency project?"
A: There are no issues with funding for the slide removal and the repairs that will be necessary to keep State Route 27 open. In addition, Gov. Gavin Newsom proclaimed a state of emergency on May 3 to help fund badly needed repairs of roads battered during this year's storms, including State Route 27 (Topanga Canyon Boulevard). The proclamation enables Caltrans to request funding from the Federal Highway Administration's Emergency Relief Program, which could cover up to 100% of the repairs, according to the governor's office.
Q: "Who is the contractor for this emergency project?"
A: The contractor is Flo Engineering of West Covina, CA.
Other Sources:
Governor's Announces Reopening of SR-27
Topanga Canyon Images May 29, 2024
Topanga Canyon Images April 23, 2024
Toks Omishakin California Secretary of Transportation
Los Angeles County Supervisor Lindsey Horvath
State Assemblymember Jacqui Irwin
Los Angeles County Public Works