1977 Volume 39 Issue 2 Pages 65-76
There are several drift type perennial snow covers at niches of 1300-1900m above sea level on the southern slope of Mt. Chokai (2237 m, N 39°06, E 140°03') where are lee side places of the winter northwest monsoon. These snow covers turn to ice packs in a year after the snowfall season since the very large depth of snow cover.
During the survey of 1972-1976, the Kai-gata (shell shape) Glacieret at the height of 1400 m, one of these perennial snow (and ice) covers, showed the ablation depth of about 30 m/year and the notable interannual mass variation. In the 1974 spring airborne photogrammetry, the maximum depth of snow cover was estimated at > 45 m after the heavy snowfalls of 1973/74 winter, and the mass of ice in the 1974 fall was over 20 m depth, then the glacieret flowed at a rate of about 20 cm/day during the 1975 summer season as a small niche type glacier.
In the progress of the year-to-year variation of the Kai-gata Glacieret, there are several cases of the observation of the annual boundary layer, the survey of the crystal structure of the boundary, the disappearance of the one year snow cover and the key layer by the 1974 spring eruption of the Mt. Chokai, and the ablation rate of several meter per year at the bottom of the Kai-gata Glacieret is considered.