Accumulated snow is called snowpack. During the warm season, snowmelt supplies rivers and streams. Snow covered areas also support animals that need cold, snowy conditions to survive.

Precipitation across mountains is driven by orographic lift. Air masses are forced from lower to higher elevations, causing them to cool, condense, and release moisture as rainfall or snowfall. Orographic enhancement describes the increased precipitation caused by the shape of the terrain, which forces air upward as it moves over mountains. Data inconsistencies and limitations create challenges with fully understanding this mechanism in the context of snow accumulation.

In this study, we look at snowfall patterns in the Rocky Mountains, Northern Cascades, and Sierra Nevada from 1980-2020. We analyzed 100 snowy watersheds using several snow data products and models. By comparing these different sources, we identify where they agree on the estimated amount of snow water equivalent (SWE), the spatial and temporal patterns of SWE, and how snowfall responds to changes in terrain. Snow water equivalent, or SWE, refers to the amount of water stored in snow. We also use machine learning to understand how climate and terrain features may influence snowfall. This work aims to improve water supply forecasts (i.e. seasonal streamflow).