気候変動が雪崩リスクに与える影響(Climate change may complicate avalanche risk across the Pacific Northwest)

2026-03-23 ワシントン大学 (UW)

米ワシントン大学の研究によると、気候変動が雪崩リスクの性質を変化させている。従来は低温で乾燥した雪による雪崩が主流だったが、気温上昇により湿った重い雪による雪崩が増加し、発生時期も春以降へと長期化している。特に中緯度の山岳地域では、降雨や融雪が引き金となるケースが増え、予測が難しくなっている。これにより登山者やスキー客の安全管理が一層重要となり、従来の雪崩対策や警報システムの見直しが求められている。

気候変動が雪崩リスクに与える影響(Climate change may complicate avalanche risk across the Pacific Northwest)
This map shows the change in number of “ice crust days” across the 53 monitoring sites during the simulated winter with 2 C warming. The Cascade sites overwhelmingly saw fewer theoretical ice crust days, whereas cooler inland regions overwhelmingly saw more. Photo: Alden et. al/ARC Geophysical

<関連情報>

気温の上昇により、太平洋岸北西部の寒冷地域では積雪層に融解凍結層が増加する Higher Temperatures Lead to More Melt-Freeze Crusts in Snowpacks in Cooler Regions of the Pacific Northwest

Alden, C.; Sullender, B.; Stimberis,J. & Lundquist, J.
Geophysical Research  Published: 2026-02-25
DOI:https://doi.org/10.5149/ARC-GR.2451

Abstract

Warming winters will lead to a greater fraction of rain falling in traditionally snowy areas. Here, we investigate the impact of these changes on snowpack stratigraphy, focusing specifically on the presence and duration of melt-freeze crusts. In this work, we use a hydrologic model with high vertical resolution (Structure for Unifying Multiple Modeling Alternatives, SUMMA) to test the sensitivity of melt-freeze crusts to warming. Model runs with up to 100 layers were initialized with observed precipitation and temperature for 2°C and 4°C uniform warming sensitivity tests. We found warming temperatures increased the frequency of crusts at colder sites, while warmer sites had fewer crusts. Melt-freeze crusts increase the complexity of avalanche forecasting and mitigation for highway, recreational forecasting, and ski area operations. These changes to the snowpack will also impact ecosystem function, with greater snow density altering large mammal movements and predator-prey interactions.

1702地球物理及び地球化学
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