Andrews Glacier and Tarn
Today, the park’s small glaciers are restricted to high elevations above 11,000 feet (3,350 m) and north- and east- facing cirques, where they are sheltered from the Sun’s direct rays. Local topography helps to shelter the glaciers and directs wind- blown snow onto their surfaces. In general, during the winter, blowing snow occurs over 50% of the time, with 95% of the days in January having blowing snow. On average, over 30 blowing snow events occur each winter, with each event averaging 36- hours long (Berg, 1986). Hence, glaciers in the Front Range are referred to as “wind- drift glaciers” because they receive most of their snow as wind- blown snow, which falls predominantly on the western slope and is transported to the eastern slope. Notably, these glaciers have been able to form well below regional snowline because of wind drift. Few landforms have caught the imagination of geomorphologists more than the glacial cirque: a bowl-shaped, amphitheater- like hollow or basin eroded into a mountain mass. The small glaciers that exist in the park occupy cirques once excavated by their large predecessors. After the glacier that created the cirque melts, a small lake, called a tarn, may occupy the basin. One of the most spectacular cirques is the area below the East Face of Longs Peak. Chasm Lake (a tarn) fills the basin. Other distinctive cirques in the park are located on Terra Tomah and Ypsilon Mountains.
