Report on the perennial snow patch on Mount Hakusan-its location, morphology, transition of annual net mass balance and the ablation rate in the ablation seasons

Abstract

Since 1969, in October morphometric surveys of Senjagaike-sekkei (36°09'09''N, 136°46'13''E, about 2, 570 m above mean sea level), the only perennial snow patch in the Mount Hakusan area, have been carried out. The snow patch is located at a depression on the west slope of the mountain ridge, and in late August, September and October a pond appears at the lower end of the patch. In October the dimensions of the patch are about 75 m N-S and about 60 m E-W, and the maximum snow depth is about 10 m. The morphometric maps of the snow patch in October 1976 and 1977 are displayed; the dimensions and the shape of the snow patch in these years are both representative of those in 1969-1978. The annual net mass balance was negative in average till 1972 and positive afterwards. Other available information suggests that it is likely that no or little perennial snow existed in 1964 and 1965 and afterwards the amount has been increasing.From the four successive morphometric surveys concerning the ablation process in 1973, it is concluded that the estimated annual accumulation in the winter of 1972-1973 was about 14 m in snow depth at the end of the snowfall season (April 30), and it is supposed that the maximum depth of 20 m occurred in the middle of March. The mean rate of ablation in the most active thawing period of 1973 was about 1.3 × 102 ton/day (about 11 cm/day in snow depth). The amount of the water which percolated into the depressed ground is estimated to be about 0.9 × 102 ton/day.By virtue of the penetration of the thermal-drill the absolute depth of the snow patch in October 1976 is measured.