Also: Accumulation Zone
Accumulation refers to all processes that add mass to the snow cover or to a glacier, and to the results of those processes. This includes precipitation (liquid and solid), deposition from vapor in the atmosphere (such as dew or surface hoar), wind deposited snow, avalanches, etc.
Accumulation is the opposite of Ablation.
The Accumulation Zone is the area where the snow accumulates. In relation to avalanches this is often, but not always, synonymous with the term starting zone. The term is commonly used in relation to glaciers. Glaciers gain mass over the course of a year in the accumulation zone, where the past winters snow does not all melt over the summer. Below a certain elevation the glacier loses mass because the mass lost exceeds the amount accumulated in winter - this is called the ablation zone. Late in the summer there is often a distinct line separating the whiter looking accumulation zone above from the darker ablation zone below - this is called the firn line.
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