Bolam Glacier lies on the northern flank of California’s Mount Shasta and is one of the mountain’s major ice bodies. It is the second longest glacier in the state, after Whitney Glacier, and the fourth largest on Mount Shasta by area and volume, behind Hotlum, Whitney, and Wintun. Occupying a cirque below the main summit, its moving ice begins beneath a large bergschrund at about 12,600 feet, with permanent snow and ice extending upslope to roughly 13,500 feet before descending steeply to about 9,800 feet. Surveys found it grew by about half between 1951 and 2002, even as wider western glaciers were later observed shrinking with rising temperatures.