Assessment of drought impacts on remotely sensed seasonal snow depletion patterning: A case study over the Boise River Basin, Idaho

Authors: Woodruff, Craig; QUALLS, RUSSEL - University Of Idaho; Clark, Patrick

Submitted to: Hydrological Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2025
Publication Date: 1/7/2026
Citation: Woodruff, C.D., Qualls, R., Clark, P. 2026. Assessment of drought impacts on remotely sensed seasonal snow depletion patterning: A case study over the Boise River Basin, Idaho. Hydrological Processes. 40(1). Article e70392. https://doi.org/10.1002/hyp.70392.
DOI: https://doi.org/10.1002/hyp.70392

Interpretive Summary: Climate change and drought are impacting snow accumulation and melt – a source of irrigation water for much of the Western United States. In this research we use daily remotely sensed observations of snow extent to develop the recurrent pattern of snowmelt to test whether the pattern changes under drought conditions. We demonstrate that drought decreases the snow coverage, but once the snow begins to melt the spatial coverage depletion returns to the same recurrent pattern of snowmelt that can be found using as few as 3 years or as many as 17 years of daily remotely sensed snow extent data. The nearly 5-billion-dollar agricultural crop business in Idaho relies heavily on water from snowmelt, and this research helps us understand how snowmelt is changing as a result of drought and climate change.

Technical Abstract: In this study we tested the impact of drought on patterns of snow depletion with multiple years of remotely sensed snow covered area over the Boise River Basin. Daily remotely sensed snow covered area data were downloaded for the period of 2000-2016. Composite were created and multiple composites were combined with Principal Component Analysis to derive the recurrent pattern of snow depletion. Model sensitivity to the number of years used in development (3-16) was tested, along with a statistical analysis of the inclusion of drought years in model development. We found that even with only 3 years the model of the recurrent pattern of snow depletion was 98.7% correlated with one developed using 17 years. Statistical analysis showed the inclusion of drought years in 68 models altered the pattern, but the difference was isolated to lower elevations where snow coverage was reduced in drought years. These results indicate even if less snow falls with drought that once melt begins the spatial coverage throughout melt returns to the same spatial pattern defined by any combination of three years, although the most complete pattern comes from using non drought years in model development. The repeatability of the pattern under moderate severe drought demonstrates its robust nature in a changing climate paving the way for inclusion of patterns of snowmelt as a parameter in snowmelt runoff modeling today and in future scenarios.