2.2.2 Influence of geography and wind on snow distribution
While large-scale terrain features impact snowpack on the global scale, terrain plays an even more important role in snowpack development and evolution at regional and local scales. Regional topographic features, such as mountain ranges on the scale of tens of kilometers, produce large annual snowpacks due to their influence on the prevailing atmospheric flow. Mountains force the prevailing flow upward, producing moisture-laden clouds that enhance snowfall.
Mountain ranges oriented north-south, such as the Rocky Mountains, enhance snowfall when winds are perpendicular to the mountains (from the west or east). In contrast, ranges oriented east-west, such as the Uintas, have the heaviest terrain-enhanced snowfall with southerly or northerly flow.
Terrain is even more complex at the local level, with individual peaks, valleys, moisture sources, and other features creating their own local impacts on snowpack. This results in large horizontal variations in snowpack.
In the next few pages, we will examine other factors that impact snowpack development.