Item: CLIMATE-DRIVEN CHANGES IN SNOWPACK TIMING, MAGNITUDE, AND DOWNSTREAM HYDROLOGY ACROSS WESTERN NORTH AMERICA
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Title: CLIMATE-DRIVEN CHANGES IN SNOWPACK TIMING, MAGNITUDE, AND DOWNSTREAM HYDROLOGY ACROSS WESTERN NORTH AMERICA
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Kate Hale [ Department of Geography, University of British Columbia, Vancouver, British Columbia, Canada ] [ Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska, USA ]
- Wouter Berghuijs [ Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands ]
Date: 2026-09-28
Abstract: Climate warming threatens snow-dependent water resources non-uniformly across western North America, where hydrologic sensitivities to snowpack loss and advanced snowmelt differ between mountain regions and contrasting maritime to continental climates. Communities rely on snowmelt-derived water for ecosystems, agriculture, and downstream supply, yet the physical processes shaping hydrologic sensitivity remain poorly understood, limiting predictions of hydrologic responses to changing snowpack conditions. We use directional statistics, applied to seven decades of daily hydrometeorological data across several mountain watersheds, to quantify annual runoff sensitivity to two components of snow water availability: (1) center-of-mass timing, the seasonal alignment of snowpack-derived water delivery relative to atmospheric demand, and (2) seasonal clustering, the concentration of water availability within a year. Historically, coastal, maritime-influenced regions exhibit greater sensitivity to water availability timing (e.g., Pacific Coastal Mountains, Cascades), whereas interior, continental regions exhibit greater sensitivity to seasonal clustering (e.g., Rocky Mountains), regardless of differences in climatic aridity. Although seasonal clustering has intensified in some regions and weakened in others, producing limited net change across western North America, water availability timing has advanced consistently across the study domain and is the larger contributor to declines in runoff generation, explaining the majority of the runoff ratio trends. Hydrologic vulnerability therefore depends on both regional sensitivity and the magnitude of hydroclimatic change; offering a transferable framework for anticipating where and how snow loss will most affect downstream water availability across global, snow-dependent mountain systems.
Object ID: ISSW2026_P3.60.pdf
DOI: https://doi.org/10.15788/1790099241
Language of Article: English
Presenter(s): Kate Hale
Keywords: Snow hydrology, seasonal water availability, hydrologic partitioning, runoff ratio, climate change, western North America
Page Number(s): 2487 - 2490
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