Winter damage will keep Whatcom County mountain pass closed longer than expected
Damage from winter storms will keep the North Cascades Highway closed near the summit well past its usual spring opening date, the Washington State Department of Transportation said Thursday.
Part of the scenic road was set to open from the east side on Thursday, but is expected to stay closed on the west side from milepost 130 near Diablo Lake to milepost 156 at Porcupine Creek, WSDOT’s Melissa Ambler said in a statement.
“This isn’t just clearing debris. In many places, we have to rebuild the roadway from the ground up,” Ambler said.
Damage spans several miles in the 26-mile closure zone, Ambler said. As assistant region administrator, Ambler heads WSDOT’s Mount Baker Area.
“In several locations, heavy runoff overwhelmed culverts and drainage systems, sending water over and beneath the roadway. That water washed away the material supporting the highway, leaving sections of pavement undermined. In some places, the road is no longer fully supported underneath,” WSDOT’s statement said.
Not even cyclists or hikers will be allowed through the closure point, which restricts all public access.
Highway 20, the closest road over the Cascades Mountains for residents of Bellingham and Whatcom County, closes over the mountain pass every fall or winter due to avalanche danger. It opens again in April or May, depending on snowfall and road conditions.
“WSDOT identified several locations where repairs need to be made before the road can fully reopen. Work to begin clearing the rock slide near Diablo Lake is expected to begin as soon as the week of May 4 and will be completed under a 30-day emergency contract,” the agency said.
“While WSDOT has made repairs quickly to other highway emergencies this season, this situation is different. The additional work on SR 20 between mileposts 142-148 cannot be completed under the time constraint of an emergency contract, even working around the clock, due to the extent of the damage and the complexity of the repairs,” the agency said.
Damages include:
- Embankments that washed out and must be rebuilt.
- Broken or blocked culverts.
- Reconstruction of drainage systems and ditches.
- Unstable slopes above the highway that require rock removal and stabilization.
“WSDOT recently brought prospective contractors to the sites to assess the full scope of work and prepare bids. Once a contract is awarded, repairs are expected to take several weeks, with crews working up to seven days a week where possible,” the statement said.
A timeline for repairs will depend on road conditions and scope of the damage found, according to WSDOT.
“We’re moving this work forward as quickly as we can. Our goal is to reopen the highway safely and keep people informed on the progress we are making,” Ambler said.
This story was originally published April 30, 2026 at 10:57 AM.
