Glaciers act as natural reservoirs for snow, ice, and meltwater. On seasonal time scales, ice melt and temporary meltwater storage within a glacier lead to large amounts of late-summer discharge. In many alpine streams this is the sole source of baseflow in late summer and early fall, after the seasonal snowpack has melted away.
On decadal to centennial time scales, mountain glaciers advance and retreat over the landscape, giving long-term storage and release of water. The sections below describe the general character of glacier hydrology, and the ways in which glacier cover affects regional hydrology.
The glacier surface consists of seasonal snow, multiyear firn, and glacial ice. Most of the water in mountain glaciers is produced from melting at the glacier surface. On a glacier surface, meltwater channels carve into the ice and wind sinuously downslope, sometimes pouring off the front of the glacier and sometimes plunging into deep moulins and crevasses.
Read more about Glacier Hydrology - An Overview
Hydrology of Glacierized Basins
Glaciers delay melting and runoff from seasonal snow until late in the summer. Within a glacierized catchment, they also supplement rainfall and seasonal snowmelt with meltwater from glacial ice. Within a given glacier, there can be year-to-year variations in meltwater storage and runoff.
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