In the early 21st century, glaciers cover a total of 2.5% of Adams' surface. During the last ice age about 90% of the mountain was glaciated. Mount Adams has 209 perennial snow and ice features and 12 officially named glaciers. The total ice-covered area makes up , while the area of named glaciers is . Most of the largest remaining glaciers (including the Adams, Klickitat, Lyman, and White Salmon) originate from Adams' summit ice cap.