BELLINGHAM, Wash. — This story was originally published on mynorthwest.com.
A massive mudslide near Bellingham closed all northbound lanes on I-5 on Thursday. This caused a steady 3-mile backup approaching the detour route at N. Lake Samish Road (milepost 246). Monday morning, the Washington State Department of Transportation (WSDOT) released an update on its emergency plan to expedite clearing and stabilizing the hillside.
Combined, the slides carved a debris field more than 100 feet wide between mileposts 248 and 249 and sent an estimated 2,000 to 3,000 cubic yards of debris down a 60- to 80-foot slope toward northbound I-5 lanes below.
Boulders, some as big as buses and many others larger than pickup trucks, remain unstable and unsupported. Safety concerns about more active debris movement prevented immediate cleanup from starting.
Work began Sunday, with contractors clearing trees and debris from the freeway. Crews will work around-the-clock to reopen I-5 as quickly and safely as possible, according to WSDOT. Due to safety concerns with the unstable slope, some work must take place during daylight hours.
WSDOT’s repair plan timeline
Interwest Construction Inc. has been selected by the Washington State Department of Transportation to perform the emergency work.
WSDOT will provide updates about the repair plan and timeline by Wednesday, following a full geotechnical engineering report.
Detours in effect
Drivers on northbound I-5 can expect this section to remain closed for days, with all northbound traffic exiting at N. Lake Samish Road.
WSDOT encourages drivers to use alternate routes, such as SR 11 (Chuckanut Drive) or SR 9. Freight traffic is reminded that local roads and SR 11 are not suitable for semi-trucks.
Travelers also should expect longer delays on I-5. Flaggers will control the intersection of the northbound I-5 off-ramp and N. Lake Samish Road to prioritize traffic exiting northbound I-5 during daylight hours and improve traffic flow when volumes are heaviest. WSDOT encourages people to plan ahead.
Due to the geology of the area, this location is known for slides. WSDOT maintenance crews routinely do hazard tree removal and vegetation management, and clear drains and culverts to help reduce the chances of larger slides.
A barrier was also installed along this stretch of I-5 to catch many smaller slides. But sometimes heavy rain events, such as the recent atmospheric river, can create larger slides with more debris and force highway closures.