A First-Ever Observational-Based Snowpack Climatology for the Northeastern United States

Snowpack plays a critical role in the hydrology, ecosystems, and economy of the northeastern United States, serving as a natural reservoir and impacting flood management, agriculture, and winter tourism. Currently, the National Oceanic and Atmospheric Administration (NOAA) and National Weather Service (NWS) rely on the Community Collaborative Rain, Hail and Snow Network (CoCoRAHS) and Coopertive Observing Program (COOP) to determine real-time snowpack depth and snow water equivalent (swe). The National Operational Hydrologic Remote Sensing Center (NOHRSC) utilizes these and other datasets in the Snow Data Assimilation System (SNODAS) to model high-resolution snowpack properties across the country, dating back to 2003. Despite these valuable datasets, climatological values of depth and swe do not exist for sites in the Northeastern US.

This two-year NOAA-sponsored project, which began in the summer of 2024, aims to establish the first observational-based, daily climatology of snowpack in New England and New York by leveraging a comprehensive dataset of snow depth and swe measured by various organizations. Spanning seven states, seven decades, and over 400 sites, the dataset was quality controlled using Python to remove erroneous values. Climatological normals of snow depth and swe will be calculated using a fourth-degree polynomial regression at each site. Many other metrics such as a snow drought index, median snow-out dates, and snowpack trends will be calculated and examined to offer deeper insight into regional snowpack variability.

With pronounced snowpack declines seen in the region, the implications for numerous sectors will be significant. The results from this project will contribute to a broader understanding of snowpack depth and swe in the region, helping inform water resource management and drought and flood risk assessment.