Item: WIDESPREAD WET AVALANCHES BUT A SAFE ROAD: THE MARCH 2025 WET SNOW CYCLE IN HARDANGER AND LESSONS FROM SITE-SPECIFIC FORECASTING ON E134 HAUKELIFJELL
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Title: WIDESPREAD WET AVALANCHES BUT A SAFE ROAD: THE MARCH 2025 WET SNOW CYCLE IN HARDANGER AND LESSONS FROM SITE-SPECIFIC FORECASTING ON E134 HAUKELIFJELL
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Njål Farestveit [ Geofag DoV, Statens vegvesen (The Norwegian Public Roads Administration), Bergen, Norway ]
- Markus Eckerstorfer [ Geofag DoV, Statens vegvesen (The Norwegian Public Roads Administration), Bergen, Norway ]
- Halgeir Dahle [ Geofag DoV, Statens vegvesen (The Norwegian Public Roads Administration), Bergen, Norway ]
Date: 2026-09-28
Abstract: On 4–5 March 2025, an extensive wet avalanche cycle struck the Hardanger region of western Norway, closing multiple roads through avalanche debris, slush flows and debris flows, and prompting red-level warnings from Varsom.no. E134 Haukelifjell, a major mountain pass connecting western Norway to the rest of the country, experienced the same meteorological forcing and snowpack conditions but remained open throughout the event. This paper documents the forecast-decision-action sequence behind that outcome, in the first season that site-specific avalanche forecasting and active avalanche control operated together on this road. An Orange alert level was issued two days ahead of the peak of the event, prompting preventive blasting at Pepparstein on 4 March that released a size 3 avalanche before the heaviest rainfall arrived, substantially reducing the load on the starting zone. Much of the precipitation subsequently forecast as snow fell instead as rain, further stabilizing the remaining snowpack, and no avalanches reached the road at any point. SNOWPACK simulations illustrate the wet snow processes involved but served as supporting context rather than as the basis for operational decisions, which relied on field observations, weather forecasts, and structured risk assessment. The case illustrates how early alert level elevation, well-timed preventive control, and continuous tracking of the precipitation phase transition can together keep a mountain road open during a regionally severe avalanche event.
Object ID: ISSW2026_P2.52.pdf
DOI: https://doi.org/10.15788/1790099037
Language of Article: English
Presenter(s): Njaal Farestveit
Keywords: wet avalanche, site-specific forecasting, avalanche control, road safety, SNOWPACK, Hardanger
Page Number(s): 2060 - 2065
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