Study of snow climate in the Japanese Alps: Comparison to snow climate in North America

In the case of the Japanese Alps, it is experientially known that there is a notable snow climate difference between the Japan Sea side mountains and the Pacific Ocean side mountains. For the purpose of improving avalanche safety, we studied the snow climate characteristics using meteorological and snow pit data collected from two study plots in the mountain regions. Ten years of meteorological data and 4–10 years of snow pit data were employed in the study. A snow climate classification scheme proposed in North America was used to determine the snow climate of these study plots. The general snowpack characteristics for each snow climate presented in previous studies were used in the present study to determine the snowpack characteristics of the study plots. Both meteorological and snow pit data suggested that the Japan Sea side mountains have the same characteristics as the maritime snow climate in North America. On the other hand, the Pacific Ocean side mountains have unique characteristics caused by a combination of continental and maritime climate influences. The Pacific Ocean side mountains have similar characteristics to the continental snow climate of North America, however, that climate is different in that it is characterized by a large amount of rainfall and a high predominance of faceted crystals and wet grains. We identified a new snow climate for the Pacific Ocean side mountains of the Japanese Alps, a “rainy continental snow climate.”