On the northwest face of the mountain, Adams Glacier cascades down a steep channel in a series of icefalls before spreading out and terminating at around the elevation, where it becomes the source of the Lewis River and Adams Creek, a tributary of the Cispus River. Its eastern lobe ends at a small glacial tarn, Equestria Lake. In the Cascades, Adams Glacier is second in size only to Carbon Glacier on Mount Rainier.