Snowdon Peak is a 13,077-foot mountain in southwestern Colorado’s San Juan Mountains, within the Weminuche Wilderness and San Juan National Forest. Rising steeply above the Animas River near Silverton, it is especially striking on its east side, where it gains 4,300 feet in about 1.5 miles. Visible from U.S. Route 550, the peak drains into tributaries of the Animas and takes its name from the highest mountain in Wales. Its alpine subarctic climate brings snowy winters and summer thunderstorms. Geologically, it belongs to the Uncompahgre Formation, an 8,200-foot-thick sequence of quartzite and black phyllite formed from much older marine and river sediments above ancient plutons.