2022 Volume 84 Issue 4 Pages 283-296
In this study, a numerical simulation model for snow avalanches is developed by improving a single phase fluid continuum body model of debris and mud flows. The developed model considers the development and decrescence processes of snow avalanches. The model was applied to the snow avalanches occurring at Mount Pinneshiri in February 2020 and at Nasu in March 2019 to discuss the reproducibility of the flow characteristics of the snow avalanches. Numerical simulation results show that the deposition area of the snow avalanche that occurred at Mount Pinneshiri was approximately 350 and 50 m in the flow and transverse directions, respectively, which was close to the observed snow deposition area. Further, the snow avalanche reached the burial point of casualty in 50 s after its occurrence, and the average speed of the snow avalanches on the slope was approximately 15 m/s. The flow depth deepened as it flowed down, exceeding 8 m in some areas. The time from the occurrence of the snow avalanche to its cessation was approximately 200 s. The snow avalanches occurring at Nasu were recorded using an interval camera, and the reproducibility of the avalanche propagation speed was examined using the photographs. Numerical simulation results showed that the avalanche reached the lower part of the slope in 14 s after the occurrence, similar to the observed snow avalanche and the reproducibility of the propagation speed of the snow avalanche was confirmed.
