Mountain snowpack

Among several existing classifications of seasonal snowpacks, we use that of Sturm et al. " that describes the tundra, taiga, Alpine, maritime, prairie and ephemeral snowpacks. Sturm et al. also mention the mountain snowpack, that displays such large spatial variations that it... 

Colorado is located in the interior of the United States, while California is on the coast. The resulting differences in climate lead to several important differences in the mountain snowpack in these two regions. California tends to have a... 

One of the major effects of acidic deposition is felt by aquatic ecosystems in mountainous terrain, where considerable precipitation occurs due to orographic lifting. The maximum effect is felt where there is little buffering of the acid by soil or rock structures and where steep lakeshore slopes allow little time for precipitation to remain on the ground surface before entering the lake. Maximum fish kills occur in the early spring due to the "acid shock" of the first meltwater, which releases the pollution accumulated in the winter snowpack. This first melt may be 5-10 times more acidic than rainfall. 

FIGURE 2.9 Total Hg concentrations (ng/L) in the 2002 snowpacks at snow-sampling sites in the Rocky Mountains of the United States (GP Ingersoll and others, U.S. Geological Survey, written commun., 2003). 

In areas with large snowpacks (e.g., much of the Northeast and all of the mountainous West), ions have been shown to drain from the pack in the early stages of snowmelt. This process leads to concentrations that are much higher than the average concentration of the snowpack itself (82). D ifferential elution of acid anions (like N03") during the initial stages of snowmelt has been shown to be responsible for the elevated N03" concentrations observed in parts of Scandinavia (81), Canada (82), the Adirondack Mountains (181), the Midwest (182), and the Sierra Nevada Mountains (180). Ammonium deposited to the snowpack (either wet or dry deposition) can subsequently... 

Seasonally, the melting of small glaciers and ice sheets on land provides fresh water for streams, rivers, and lakes. Over the winter, falling snow and precipitation build up in snowpacks in the mountains. When warm weather arrives in spring, both the snow and ice melt and feed local water systems. According to the U.S. Geological Survey, as much as 75 percent of the freshwater supply in the... 

Arellano L, Fernandez P, Tatosova J, Stuchlik E, Grimalt JO (2011) Long-range transported atmospheric pollutants in snowpacks accumulated at different altitudes in the Tatra Mountains (Slovakia). Environ Sci Technol 45 9268... 

Forms of precipitation other than rainfall may contain excess acidity. Acidic fog can be especially damaging because it is very penetrating. In early December 1982, Los Angeles experienced a severe, 2-day episode of acid fog. This fog consisted of a heavy concentration of acidic mist particles at ground level that reduced visibility and were very irritating to breathe. The pH of the water in these particles was 1.7, much lower than ever before recorded for acid precipitation. Another source of precipitation heavy in the ammonium, sulfate, and nitrate ions associated with atmospheric acid is acid rime. Rime is frozen cloudwater that may condense on snowflakes or exposed surfaces. Rime constitutes up to 60% of the snowpack in some mountainous areas, and the deposition of acidic constituents with rime may be a significant vector for the transfer of acidic atmospheric constituents to Earth s surface in some cases. 

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