Despite its name, it is classified as a 'perennial snowfield' because it lacks the size and movement characteristics required to be defined as a glacier.
The glacier is a remnant of the Little Ice Age and persists due to its north-facing orientation, which limits direct sun exposure.
The base lake, St. Mary's Lake, is a popular spot for fishing, though it remains cold throughout the summer months.
It serves as a primary training ground for Front Range skiers looking to extend their season into the summer months.
The area is prone to sudden, severe lightning storms in the afternoons during the summer season.
St. Mary's Glacier is technically a perennial snowfield rather than a true glacier, located at an elevation of approximately 10,800 feet in the Arapaho National Forest. It serves as a popular year-round destination for backcountry skiing and hiking near the Continental Divide. The trail to the snowfield is approximately 1.5 miles round-trip with an elevation gain of roughly 700 feet. The site features a scenic alpine lake at its base, which collects meltwater from the snow above. Hikers traverse a mix of rocky terrain and loose scree to reach the snowfield edge. It is a high-altitude environment where rapid weather changes are common throughout the year. The site is maintained through a combination of public and private land management, requiring visitors to respect designated trail boundaries.
The shoreline of St. Mary's Lake looking upward toward the snowfield.
Start your hike early in the morning to avoid the high probability of afternoon thunderstorms.
Wear sturdy, broken-in hiking boots, as the trail surface consists of uneven rocks and loose scree.
Bring extra layers even in summer; temperatures at 10,800 feet can drop significantly if cloud cover moves in.
Do not attempt the hike if you are not acclimated to high altitude; avoid wearing casual footwear like flip-flops or sneakers.
Accessible year-round, though winter access is highly dependent on road conditions and snowpack; the upper parking lot may require 4WD in winter.
Stay on the marked trails to prevent alpine tundra erosion; leave no trace of trash; yield to uphill hikers.
