| Term: | Ablation area |
| Definition: |
The area of a glacier where more glacier mass is lost than gained. NSIDCCryosphere
Ablation area is the lower region of a glacier where snow ablation exceeds snowfall. A line that marks the limit on a mountain above which snow persists from one winter to the next is called the annual snowline, and this line on a glacier is called the firnline. Above the firnline, snow that falls each year packs down and changes into glacier ice as air is slowly forced out of it. This part of the glacier is its accumulation area where more snow falls each year than is lost by melting. Below the firnline is the ablation area, where melting predominates. A synonym of ablation zone. IHPGlacierMassBalance That portion of a glacier surface below the firn line where ablation exceeds accumulation; the opposite of accumulation area. AMSglossary GCW |