North Cascades Highway to close for several days next week for culvert, bridge work

Highway 20 will be closed for four days next week near Marblemount at as culvert on Olson Creek is removed to allow easier passage for fish, especially salmon.

A detour is planned at Rockport while the road is blocked, the Washington State Department of Transportation said in an email.

Highway 20, also called the North Cascades Highway, is the state’s northernmost mountain pass. Full closure is from 6 a.m. Monday to 6 a.m. Friday.

Crews will remove the existing culvert, build a new bridge and retaining walls, WSDOT said.