2020 年 126 巻 3 号 p. 149-156
Glaciological studies have been conducted on snow patches in Japan since 1910th, including the recent identification of active glaciers in the Hida Mountains. This identification was presented at an open symposium organized by the Data Center for Glacier Research of the Glaciological Society of Japan, which recognized that the snow patches have a considerable mass of ice that shows evidence of downward flow along a valley. International cryosphere-related organizations, however, have defined the glacier as a “stagnant or flowing ice mass”, and the international classification of glaciers as published by The International Commission of Snow and Ice (ICSI) requires the criterion of flow for only certain classes of glaciers, such as the valley glacier etc. The presence of ice flow is not considered necessary to define mountain glaciers and glacierets. On the basis of a pilot study in the Himalayan region as used by the ICSI, several snow patches with ice masses in Japan can be considered as a type of glacier. However, the classification is unclear in terms of criteria based on flow, size, and thickness of an ice mass, as well as in terms of distinctions between valley glaciers, mountain glaciers, glacierets, and snow patches, which should be re-examined and clarified to create a better definition and classification of snow and ice masses on Earth.
