South Cascade glacier: the moderating effect of glaciers on runoff

Runoff and water balance measurements made at South Cascade Glacier and other glacierized basins in the North Cascades demonstrate the role of glaciers in moderating runoff. The summer runoff from mountain drainage basins that do not have glaciers is highly variable from year to year. Drainage basins that have only a small fraction of glaciers have a natural variance which is considerably less. The mechanisms that cause this decrease in variance are: (1) The increased albedo of a glacier surface during years of high snowfall results in decreased ablation, hence less runoff. During years of low precipitaiton and less snowfall, much more low albedo ice is exposed and runoff is increased. (2) The release of liquid storage from within the glacier is nearly independent of climatic variations and also acts as a runoff moderate.(moderator?)