The Sourdough Mountain lookout is one of the most popular destinations for hikers in the North Cascades. With over a thousand feet per mile on the five-mile climb, it’s not easy to get to, but the 360-degree view at the top is well worth the effort. The lookout was built in 1933 to spot forest fires. Nowadays, the peak is used to look at Ross and Diablo lake surrounded by mountains and glaciers. The ten-mile out and back to the lookout from the tennis courts in the Diablo Community Park, where the Sourdough Mountain Trailhead is located. However, a 23-mile loop climbing Sourdough Mountain and using Pierce Mountain Way, Ross Dam Trail, Diablo Lake Trail, and a couple of connecting roads makes a fine outing.
The trail climbs over 3000 feet through dense forest in the first 2.5 miles, with a few glimpses of Colonial and Pyramid Peaks through the trees. The trail enters North Cascades National Park and then the turquoise colors of Diablo Lake come into view. Roll through meadows for the next couple of miles and cross Sourdough Creek and enter Sourdough Camp. Make a decision at this junction to continue escalating 1.5 miles to Sourdough Mountain or stay on the trail to the lookout.
For this article, we will continue as the scenic mountains and lakes extend in the landscape on the climb. At the ridge, Hozomeen Mountain is seen towering over Ross Lake. A little farther to the east is Jack Mountain. Flip around, and the Pickets appear to the Northwest.
Continue onto Pierce Mountain Way to complete the loop. This trail is less traveled and will require some bushwhacking, and it’s almost as steep as the Sourdough Mountain trail, so keep the quads intact in the 5.2 miles heading back out of the National Park to the Ross Dam Trail. Turn right on Ross Dam and follow the lake back to the dam. This section is fairly flat and well maintained. Several bridges cross streams that allow views to a few waterfalls. The trail crosses the Ross Lake Dam.
Do not go to the Dam trailhead. Continue straight on the road to Diablo Lake Trail. Cross a bridge over Riprap Creek. A mile-long climb after the bridge goes away from the lake but offers views of the dam and Ruby Mountain. The trail continues for four miles through dense forest and a few boulder fields until it reaches Diablo Dam Road. Stay on the road until the dam is reached. DO NOT CROSS THE DAM! Turn right on the road just before the dam and follow power lines. Look for an access pass about a quarter of a mile from the dam. If you reach the end of the road, you’ve gone too far. The access path ends back in Diablo and to the Sourdough Mountain Trailhead.