What is the term for the area of a glacier where snow accumulates?

The area of a glacier where snow accumulates is called the accumulation zone. It is usually found at higher elevations, where snowfall and other additions of frozen water exceed losses from melting, evaporation, and sublimation.

Over time, repeated snowfall is compacted into firn, a granular intermediate stage between snow and glacial ice. Continued burial and pressure eventually transform the firn into dense glacier ice. That ice then flows downslope or outward under gravity, feeding the glacier’s lower reaches.

The accumulation zone is separated from the ablation zone by the equilibrium line, where annual accumulation and annual ice loss are approximately equal. The boundary can shift from year to year with weather and climate conditions. The terminus, by contrast, is simply the glacier’s lower end; it may advance or retreat depending on the glacier’s overall mass balance, not merely on whether snow is accumulating at its upper end.