North Cascades National Park

North Cascades National Park

Sourdough Mountain Trail

he Sourdough Mountain Trail forms a semi loop 13.3 miles long from the town of Diablo to Sourdough Lookout to Ross Dam. The fire lookout is the main destination of most hikers who either begin from Ross Dam or Diablo. The route from Diablo is five miles long and very steep. The route from Ross Dam is almost eight and a half miles long, but with a moderate grade. Both trails are noted on the Park Service brochure of North Cascades National Park. This description details the shorter steeper route from Diablo.

Begin this hike behind the enclosed swimming pool in Diablo. The trail begins to switchback immediately as it climbs the southern slopes of Sourdough Mountain. After the first set of switchbacks the trail makes a long traverse to the northwest then turns eastward and returns to the southern aspect of the mountain. The last mile to Sourdough Camp is a straight shot up the slopes immediately south of the peak. The saving grace of this climb is that it leads over thickly forested slopes that provide lots of shade.

Sourdough Camp lies near 5,250 feet approximately four miles from Diablo. Once you reach this primitive camping site the climb is essentially finished. The trail turns eastward from the camp and immediately crosses Sourdough Creek. It ascends slightly while traversing the southern aspect of Sourdough Mountain. A few switchbacks bring hikers to the summit ridge, which you'll follow for a quarter mile to the fire lookout.

This lookout site was first established in 1915 and the present structure was built in 1933. The site is well maintained as a historic landmark, although it is not open to the public. You'll enjoy the panoramic views from this site and understand why it was chosen as one of the first lookout sites in the forest service program.

A short distance northeast of the fire lookout is Pierce Mountain Camp. This primitive camping site lies at 5,085 feet. A permit is required for overnight use of this site.

North Cascades National Park, 700 Rayovac Drive, Suite 100 , Sedro-Woolley, WA, 98284-9314, Phone: 608-264-5610


Directions from Ross Dam Parking Area: Travel west on Highway 20 to mile marker 126. Turn right and cross the Diablo Dam. Drive into the community of Diablo and park near the enclosed swimming pool. The trail begins behind the pool.