Temperature Induced Changes In Snowpack Stratigraphy At Niwot Ridge, CO
Burton, Jonathan 1 ; Knopp, Kevin 2 ; Koester, Tai 3 ; Oliver, Micheli 4 ; Van Saghi, Justin 5 ; Wiederaenders, Luke 6
1 University of Colorado Denver
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Faceting in mountain snowpacks is facilitated by the presence of steep temperature and vapor pressure gradients over relatively small vertical distances. Colorado, particularly the Front Range, is characterized by shallow continental snowpacks where steep temperature gradients are commonplace, resulting in pronounced layers of faceted snow (or temperature gradient snow, TG). Climatological observations at the Niwot Ridge LTER over the period 1952 to 1998 have shown warming trends in the montane and subalpine zones and a slight cooling trend in the alpine (Pepin & Losleben, 2002). Such changes may have significant effects on snowpack stratigraphy, perhaps most notably the prevalence of faceting. With increased warming, we might expect less faceting as a result of a potentially reduced temperature gradient. As winter temperatures warm, the typically colder ambient air temperature may more closely match the warmer temperatures of the snow-ground interface. Few studies have evaluated the correlation between snowpack stratigraphy and wintertime air temperature. There is therefore a need to evaluate how snowpack stratigraphy responds to variations in climate, particularly given the high likelihood of future warming in the Rocky Mountains. In this research, we will use snow pit observations of snowpack stratigraphy and air temperature data from the alpine Saddle site (site 006) and the montane C1 site. This study will investigate the long-term variation in snowpack stratigraphy over the period from 1995 (the beginning of stratigraphy observations) to 2016, determining if a significant correlation exists between wintertime air temperature and the relative proportions of TG and equitemperature (ET) snow at the two field sites. Any shifts in the proportion of TG/ET snow may have considerable impacts on the mountain snowpack, with potential for significantly altering winter avalanche hazards.
Pepin, N., & Losleben, M. (2002). Climate change in the Colorado Rocky Mountains: Free air versus surface temperature trends. International Journal of Climatology,22(3), 311-329.