Item: CHALLENGES WITH REMOTE AVALANCHE CONTROL SYSTEMS (RACS) TROMS COUNTY, NORTHERN NORWAY
-
-
Title: CHALLENGES WITH REMOTE AVALANCHE CONTROL SYSTEMS (RACS) TROMS COUNTY, NORTHERN NORWAY
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Andreas Persson [ Troms County Council, Troms, Norway ]
- Mariia Pihlainen [ Troms County Council, Troms, Norway ]
- Kaja Krogh [ Troms County Council, Troms, Norway ]
- Una Bratlie [ Troms County Council, Troms, Norway ]
- Simen Bekkevoll [ Troms County Council, Troms, Norway ]
- Håvard Haukenes [ Troms County Council, Troms, Norway ]
Date: 2026-09-28
Abstract: Troms County Council (TFK) operates two different Remote Avalanche Control Systems (RACS). Along County Road 7768 in Grøttfjorden, 11 Wyssen towers are installed (Krogh et al., 2022). Along County Road 7940 on Arnøya, 23 O'BeIIX+ units are installed by MHM AS, supplied by MND Safety (Berger et al., 2024). TFK is generally satisfied with the performance of both systems, and it's clear that RACS works very well as a mitigation method. This article, however, will focus on the challenges encountered, rather than the successful operational outcomes. In Grøttfjorden, we have experienced occasional failed detonations (duds). The issue was particularly prominent during the 2023/24 season and was caused by faulty detonators. There have been no duds after changing the supplier of detonators. The handling of duds varies depending on operational conditions and the assessed risk level. The occurrence of duds and partial detonations creates additional stress for involved personnel and requires specific mitigation measures before the road can reopen. The incidents in Grøttfjorden have demonstrated that duds can occur, and despite improvements made it is reasonable to assume that a residual risk will always remain. Consequently, there has been a need to develop improved procedures for handling duds in Grøttfjorden. On Arnøya it quickly became evident that the selected trigger points were far from optimal. As the first winter progressed, several units were increasingly affected by heavy snow loading. In March 2025, a natural size-D3 avalanche destroyed one unit, and two additional units were damaged by other avalanches. Based on our experience, these issues were likely caused by a combination of limited planning time, an incomplete understanding of the design limitations of the system, and an unclear distribution of responsibilities regarding the detailed design of installation points. To avoid similar challenges in future projects, several important steps have been identified and acknowledged. A thorough understanding of avalanche dynamics, and the design limitations of the proposed RACS system is essential. Based on the lessons learned from Arnøya, it is our belief that primary responsibility of the detailed design should rest with the infrastructure owner, rather than the RACS supplier.
Object ID: ISSW2026_P4.4.pdf
DOI: https://doi.org/10.15788/1790099352
Language of Article: English
Presenter(s): Andreas Persson
Keywords: RACS, Grøttfjorden, Duds, Arnøya, Damaged
Page Number(s): 321 - 328
-