Item: MUCH ADO ABOUT SLUSHING
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Title: MUCH ADO ABOUT SLUSHING
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Susanne Eide Haug [ Department of Geosciences, UiT The Arctic University of Norway, Norway ]
- Louise Vick [ Department of Geosciences, UiT The Arctic University of Norway, Norway ]
- Alfred Hanssen [ Department of Geosciences, UiT The Arctic University of Norway, Norway ]
- Yoichi Ito [ NIED National Research Institute for Earth Science and Disaster Resilience, Japan ]
- Satoru Yamaguchi [ NIED National Research Institute for Earth Science and Disaster Resilience, Japan ]
- Chris D'Amboise [ Tromsø, Norway ]
- Dieter Issler [ NGI Norwegian Geotechnical Institute, Norway ]
Date: 2026-09-28
Abstract: Slush, or soaked now, is a poorly understood endmember of the wet–dry snow continuum that can produce fast, damaging flows. A commonly cited threshold for slush formation is a liquid water content (LWC) of ~15%, but that value remains largely untested. We performed rotating-drum experiments to observe how snow–water mixtures evolve under shear and how LWC, structure, and mechanical reworking control flow regime and morphology. LWC was varied between 0 and 100% by controlled additions and removals while we recorded material dynamics and flow modes. As LWC and mechanical reworking increased, behaviour progressed from dry granular flow to structured flow, then wet snow, slush, and finally slurry. By progressively adding and removing snow and water we found that different experimental runs showed different flow behaviour at the same LWC. Transitions between regimes were not governed by LWC alone but by the coupled effects of LWC, snow microstructure, mechanical history, rotation rate, and boundary conditions over time. Applying these laboratory findings to field settings suggests that slushflow initiation and evolution are sensitive to snowpack history and terrain morphology, and that when encounters with drainage pathways abruptly increase water content the knock-on effects are a change in flow regime, runout, and damage potential. We recommend new considerations for uptake in dynamic runout modelling, together with improved documentation of slushflow events, to improve data harmonisation in future hazard studies.
Object ID: ISSW2026_P1.66.pdf
DOI: https://doi.org/10.15788/1790098884
Language of Article: English
Presenter(s): Louise Daines-Vick
Keywords: slushflow, soaked snow, snow laboratory experiments, rotating drum experiments, runout and hazard analysis.
Page Number(s): 2480 - 2486
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