Sourdough Mountain Lookout–Trail is 5.5 miles long and one mile straight up!

The view of Diablo Lake from Sourdough Mountain is a Northwest Classic.

The view of Diablo Lake from Sourdough Mountain is a Northwest Classic.

Quick Facts:

Location: North Cascades Highway

Land Agency: North Cascades National Park

Roundtrip: 11.0 miles

Elevation Gain: 5,100 feet

Green Trails Maps: Diablo, WA-No. 48

Access: From Marblemount, follow the North Cascades Highway (SR 20) east for 20 miles. Turn left onto Diablo Road and proceed 0.7 mile crossing an iron bridge spanning Stetattle Creek. Bear right reaching the trailhead in 0.25 mile.

Note: Dogs prohibited.

Contact: NCNP Visitors Center

Good to know: wildflowers, historic fire lookout, wilderness regulations apply, practice Leave No Trace Principles

One of the most grueling hikes in the North Cascades, Sourdough Mountain Lookout is also one of the most mind-blowing for views. It’s one of my 100 Classic Hikes of Washington and a personal favorite. An arduous haul to an historic lookout, it’s worth every ounce of sweat you’ll expend. And you’ll expend plenty! A mile straight up and five and half on the ground, can you say steep? But, a priceless panorama of craggy, spiraling, glacier-hugging, cloud-piercing, unbelievably breathtaking peaks is the payoff! And directly below as an added dividend: Diablo Lake’s surrealistic turquoise-tinted waters.

From a lowly elevation of 900 feet, waste no time heading up. Switchback relentlessly, gaining 3,000 feet in the first two DSC03319miles.Approaching the North Cascade National Park border, the grade eases somewhat, but it’s still no walk in the park. Thinning forest provides sneak peeks of surrounding peaks; a much needed enticement to push on.

At 4.0 miles, reach Sourdough Creek with its camps (permits required) and the beginning of supreme subalpine walking. Traverse subalpine forest groves and sprawling meadows that burst in summer with wildflowers. Take in stunning views of Ruby Mountain, Pyramid Peak, Colonial Peak and its massive glacier. Diablo Lake’s turquoise waters twinkle one mile directly below. One last set of switchbacks is now all that’s left from keeping you from reaching the lookout.

Alas, reach the broad summit ridge of Sourdough Mountain. Behold nearly the entire North Cascades kingdom before you. To the north it’s Mount Prophet, Hozomeen Mountain, Ross Lake and the wilds of British Columbia. At more-than 9,000 feet, Jack Mountain dominates the eastern horizon. To the south it’s Colonial and company, while the Pickett Range commands your attention to the west.

The fire lookout was constructed in 1933. It is listed on the National Historic Lookout Register and is still occasionally staffed. With old glory flapping defiantly in the mountain breezes, it appears as a sentry post to America’s wild backcountry. Beatnik poet Philip Whalen worked a couple of summers on Sourdough as a lookout back in the 1950s. Talk about the ideal work environment! Linger long and rest up for the knee-jarring descent.

For detailed information on this hike (including mileage, elevation and maps) and other stunning hikes throughout the state, pick up a copy of my best selling 100 Classic Hikes Washington (Mountaineers Books)!9fe142a9-db8e-4f6f-aaec-ce9adf30c1e0

For Information on where to stay and dine along the North Cascades Highway, consult Northwest TripFinder


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