glacial retreat
when the position of a mountain glacier's terminus is farther upvalley than before; occurs when a glacier ablates more material at its terminus than it transports into that region.
Image
Muir Glacier, Glacier Bay National Park and Reserve's White Thunder Ridge as seen on August 13, 1941 (left) and August 31, 2004 (right).
2004: B. Molnia, USGS; 1941 W. Field., archived in the Long-Term Change Photograph Pairs Special Collection in the Glacier Photograph Database
Topic(s):
glaciers