Northbound Interstate 5 remains closed near Bellingham following a mudslide that struck south of the city last week, depositing rocks, trees, and debris across the travel lanes at the North Lake Samish exit near milepost 246. As of this weekend, Washington State Department of Transportation crews have mobilized to begin debris clearing and slope stabilization, but no estimated reopening date has been set. The closure is affecting approximately 50,000 vehicles per day, forcing that traffic onto city streets and alternate state routes.
The slide occurred on northbound I-5, sending material from a hillside above the highway down across the travel lanes in the area between Chuckanut Drive and the Bellingham city limits. Stabilization of the slope has to come before full debris removal can proceed safely, a process that involves geotechnical assessment, controlled material removal, and structural reinforcement of the hillside. WSDOT has indicated the work is complex and extensive, which is why no timeline has been offered to the public.
Whatcom County officials have been coordinating closely with WSDOT and city partners to manage the traffic disruption. The Whatcom County Sheriff's Office has increased patrols along detour routes to address speeding and other traffic concerns. Freight and large vehicles are directed to exit northbound I-5 at Cook Road and take State Route 9 north. Semi-trucks are specifically prohibited from using SR 11 (Chuckanut Drive) or the old US-99 alignment via Samish Way, as neither road is designed for heavy loads or vehicles of that size. Passenger vehicles have more flexibility and can use SR 9, SR 11, or local Bellingham routes as conditions allow.
The City of Bellingham has responded to the surge in traffic by adjusting signal timing at key intersections in Fairhaven, along Samish Way, and along the Yew and Woburn Street corridor. The city has also deployed radar-equipped speed trailers on Samish Way to help moderate speeds through the affected stretch. Despite these measures, the city has been clear that with tens of thousands of additional vehicles per day rerouted through city streets, traffic impacts will continue until the interstate reopens.
For residents who regularly commute through south Bellingham or into the county from points south, the practical implications are significant. Routes that typically handle a fraction of that traffic volume are now carrying far more than they were designed for. Samish Way, which runs through residential and commercial areas of Bellingham, has been particularly affected. The Fairhaven neighborhood, which connects to the interstate via the Harris Avenue and Old Fairhaven Parkway corridors, has also seen elevated through-traffic.
This is not the first time that the geography of Bellingham and Whatcom County has created serious transportation challenges. The county sits at the northern end of the Puget Sound corridor, with I-5 serving as the primary north-south spine connecting the region to Seattle and points south. When that spine is disrupted, the limited network of alternate routes gets overwhelmed quickly. SR 11 through the Chuckanut Mountains is scenic but narrow, with tight curves and no shoulders adequate for semi-truck traffic. SR 9 through the Nooksack Valley is a workable freight alternative but adds significant time and mileage to any trip originating south of Bellingham.
Whatcom County Public Works has also been dealing with a separate set of road challenges stemming from wind and wet weather. Several county roads have been flagged for water over the roadway conditions, and downed limbs from earlier wind advisories have required cleanup across the road network. Residents can check the latest county road status at the Whatcom County road closures and restrictions page.
The situation is also worth monitoring for anyone planning travel toward the North Cascades. A separate closure on Highway 20 near Diablo Lake, related to a rockfall at milepost 130, has left that mountain route closed with no estimated reopening date either. For eastbound travelers and anyone planning recreational trips into the North Cascades, that means the southern mountain access point remains unavailable until WSDOT completes stabilization and debris removal there as well. Full details on that closure were covered in a recent report with the latest Highway 20 closure update here.
Residents and commuters are encouraged to limit unnecessary trips where possible and to stay current with WSDOT alerts. The agency posts real-time updates to its travel conditions page, and their social media channels have been active with closure-related information throughout the incident. Patience from the community has been specifically requested by both the city and county, who acknowledge the disruption is substantial and unavoidable until the interstate can be safely reopened.
