Effects of Wind Flow and Topography on Snow Distribution and Liquid Water Content in Mountain Snowpacks

Abstract:

Quantifying snowmelt behavior is valuable for understanding snow’s implications for water availability, flood risk, and ecosystem health. Building off of current analyses of observed lateral movement of liquid water through snow, this research used repeat ground penetrating radar (GPR) derived liquid water content maps and terrestrial Light Detection and Ranging (LiDAR) derived snow depth maps to explore the effects of wind and topography on the distribution of liquid water within a snowpack on Niwot Ridge, Colorado. Observations of wind speed and direction were combined with a simplified linear turbulence model to produce distributed estimates of wind speed for this alpine basin. In this presentation, we assess how wind-driven snow accumulation and redistribution impact the subsequent patterns of liquid water in snow during the melt season. Using linear regression models relating topography and liquid water estimates, we explore the physical controls on snowmelt water availability. In areas of deep snow, wind flow patterns play a critical role in determining the storage and transmission of liquid water in the snowpack. The GPR and LiDAR data indicate that meltwater tends to collect at the interfaces of the snow layers, largely governed by wind dynamics, and this water moves rapidly along these interfaces to streams and rivers. We discuss how improved model representation of in-snow liquid water may be achieved through the aforementioned detailed measurements and analyses.