Item: MEASURING THE RESISTIVE FORCE OF SHRUBS ACTING ON A GLIDING SNOW SLAB
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Title: MEASURING THE RESISTIVE FORCE OF SHRUBS ACTING ON A GLIDING SNOW SLAB
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Takafumi Katsushima [ Tohkamachi Experimental Station, Forestry and Forest Products Research Institute ]
- Takane Matsumoto [ Research Institute for Natural Hazards and Disaster Recovery, Niigata University ]
- Kenichi Oda [ College of Science and Technology, Nihon University ]
- Ayana Miyashita [ Center for Forest Damage and Risk management, Forestry and Forest Products Research Institute ]
- Yuta Katsuyama [ Tohkamachi Experimental Station, Forestry and Forest Products Research Institute ]
- Katsuhisa Kawashima [ Research Institute for Natural Hazards and Disaster Recovery, Niigata University ]
- Yukari Takeuchi [ Tohkamachi Experimental Station, Forestry and Forest Products Research Institute ]
- Tsutomu Iyobe [ Research and Development Center of JR East Group, East Japan Railway Company ]
Date: 2024-09-23
Abstract: A glide-snow avalanche is triggered by snow gliding at the interface between the snow and the ground. The roughness of the ground, the presence of vegetation, and the existence of liquid water influence the friction on the ground. Shrubs and small tree are typical vegetation in avalanche-starting zones in Japan that support the snow slabs and reduce gliding. Understanding the magnitude and variations in the resistive force of vegetation is crucial for forecasting glide-snow avalanches on slopes with vegetation cover, designing technical avalanche protection measures, managing ava-lanche protection forests in avalanche-starting areas. Using strain gauges, we measured the tensile strain on the trunks of small tree which has a shrub like shape trunk buried in the snow slab in the avalanche-starting zone. We determined the resistive force exerted by the small tree on the snow slab until just before the release of the avalanche. We conducted measurements on two small trees of different sizes over two snow seasons. The measurements showed that larger tree exerted a larger resistive force. The maximum resistive force values appeared at the earlier of the snow season, after which the resistive force gradually decreased. The maximum values for each tree remained similar in the two winter seasons. However, the timing of the appearance of these maximum values and their subsequent decrease varied for each tree and year. In years when the maximum force appeared late, the release of the glide-snow avalanche also occurred late. Deformation of the trunk due to snow loads and wet metamorphism of the snow layer where the tree is buried may decrease the resistive force of the tree.
Object ID: ISSW2024_P4.3.pdf
Language of Article: English
Presenter(s): Takafumi Katsushima
Keywords: glide-snow avalanche, vegetation, resistive force, strain gauge, protection forests
Page Number(s): 603 - 608
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