Rio Grande Pyramid is the lone, symmetrical cone that stands up along the Continental Divide in the Weminuche Wilderness, near the headwaters of the river it is named for and about 25 miles south of Lake City. With more than ten miles of separation from any higher ground, it is easy to pick out from summits all over the San Juans. The Wheeler Survey reached the top in 1874. Just south, a notch cut through a volcanic dike called The Window makes a fine side trip or photo stop.
The usual start is Thirtymile Campground above Rio Grande Reservoir, reached on graded dirt roads by passenger car. The standard route follows the Weminuche Creek trail to Weminuche Pass, a popular backpacking camp, then follows the trail toward Opal Lake through high alpine terrain before a rocky final climb. From the pass the summit is about 4.75 miles and 3,400 feet; from the trailhead the full round trip runs close to 20 miles with more than 4,700 feet of gain. The terrain is Class 2, but the last stretch is loose, broken volcanic rock that deserves slow, deliberate steps.
Summit views reach the Grenadier and Needle ranges. The approach passes through beetle-killed forest and wet willows, and black bears live here, so store food properly at camp. Summer thunderstorms build quickly over the Divide, which argues for an early start from Weminuche Pass.
