A historic landmark, near the summit of Sourdough Mountain, one of the first fire lookout points was established by the United States Forest Service in 1915. Glee Davis built the original lookout in 1917. The present building dating to 1933, was rehabilitated in 1998-99. "Bush" Osborne chose the location to test his fire locating device. The Osborne Firefinder soon became standard equipment in lookouts.
The true summit of the mountain is not often visited because it lacks prominence and can be difficult to distinguish from other high points along Stetattle Ridge
. The lookout is located downhill from the high point, 1 mile to the southeast. From where the standard route trail crests the top of the ridge, either head downhill for a quarter mile to the lookout (48.742784, -121.109516), or uphill for 3/4 miles to search for the high point (48.749747, -121.126012). In late summer there are a number of tarns to swim in along the top of the ridge.
Because the standard route (the Sourdough Mountain Trail) gains 5100 feet in 5.2 miles, the mountain tends to be unpopular with the athletically-challenged. However, it is extremely popular with the athletically-gifted, as the trail represents a steep and strenuous workout. The other route (the Pierce Mountain Approach) is 8.3 miles yet less steep. Because it begins across Ross Lake, it logistically tends to be more difficult.
Camping in Winter
Views of Diablo Lake, Davis Peak, McMillan Spires, Elephant Butte, Hozomeen Mountain, Jack Mountain, Ruby Mountain, Colonial Peak, Snowfield Peak, Pyramid Peak and many others are astounding.
The following track mark shows both trail routes and can be downloaded for GPS use with the link at the top of the page. Notice that this track log does not go to the true summit, but both the location of the lookout and summit are represented with waypoints.
Swimming in a Tarn
The Sourdough Mountain Trail begins behind the domed swimming pool in the town of Diablo, at milepost 126 off State Route 20. The Pierce Mountain route begins 2.5 miles (4 km) from the Ross Dam Trailhead (milepost 134, State Route 20) on Big Beaver Trail.
Ruby Mountain View
A permit (no charge) is required for all overnight stays in the backcountry. Pets are prohibited in the North Cascades National Park.
When To Climb
Davis Peak View
The Sourdough Mountain Trail tends to be climbed in the summer, as the switchbacks are easier to surmount. Climbing out of season is not recommended due to the minor yet still reasonable (and evident towards the summit) avalanche hazard.
Jack Mountain View
Camping is available in two designated camps along Sourdough Ridge. Sourdough Camp is 4.2 miles (6.8 km) from Diablo trailhead and Pierce Mountain Camp is 0.5 mile (0.8 km) NE of the lookout. Bring a stove. Fires are not permitted in the fragile subalpine areas of the National Park.
Stop by the Wilderness Information Center in Marblemount (360-873-4500 ext. 39).