//
Photo: Dan Huntington from Anacortes, WA, CC BY-SA 2.0 via Wikimedia Commons
The dam built in Diablo Canyon, a solid granite gorge with vertical walls rising 160 ft from the river bed. When it was completed in 1936, Diablo Dam was the tallest dam in the world at 389 ft.
Diablo Dam is one of three dams along the upper Skagit River in Whatcom County, Washington and part of the Skagit River Hydroelectric Project that supplies Seattle with some of its power needs. The dam was built in Diablo Canyon, a gorge of solid granite with vertical walls rising 160 feet (49 m) from the river bed, yet were less than 100 feet (30 m) apart. Construction began in 1927, and was completed in 1930. The dam began generating electricity in 1936. The town of Diablo was established to house the workers building the dam.
© OpenStreetMap contributors
North Cascades Institute, in partnership with Seattle City Light, offers boat tours of Diablo Lake and the Upper Skagit Valley.
This brilliantly blue reservoir is flanked by some of the steepest slopes in the park. The turquoise hue of the lake's water is attributed to surrounding glaciers grinding rocks into glacial flour that stays suspended in the lake.
Walk the short interpretive trail to see Gorge Lake and Gorge Dam. Also stop on the Gorge Creek Bridge to spot Gorge Creek Falls in the ravine behind the highway.
This reservoir stretches past the Canadian border, flanked by some of the most jagged mountains in the entire range, especially Hozomeen Mountain. A pair of overlooks describe the geologic history and the writers who have been inspired by the North Cascades.
At 4855 ft, a viewpoint and a popular trailhead for the Pacific Crest Trail.
Washington Pass is the highest point on the highway at 5477 ft. A short walk to a scenic vista showcases the highway winding below the Liberty Bell and the Early Winters Spires.