According to the historical record of the Ichinokura snow patch, it disappeared in 1893, 1948 and 1973. This paper is based on the observations of the snow patch from May to December, 1976 and 1977, and 1976 was also the year of disappearance. Though the maximum depth of 3.7 m at Tenjindaira was unusually low in 1976, the snow patch remained up to the beginning of November due to the low air temperature, which was about 2°C lower than the average, during the melt season. In 1977, the maximum snow depth at Tenjindaira was 4.9 m, slighly deeper than the average, and the snow patch had an area of 7, 000 m² and volume of 21, 000 m³ at the end of October, due mainly to the low air temperature in the melt season, being 34°C lower than the normal, and the volume was 9, 000 m³ in December, so that the patch lasted throughout the year.

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In the Karasawa cirque (36°17'N, 137°40'E) of the Hotaka massif, observations of the perennial snow patch, especially its size, were taken from 1968 to 1976. The size at the end of every ablation season ranged from 10⁴ to 10⁵ m², and its average was 5.7 × 10⁴ m². Snow ablation from May 3 to October 10, 1976, is about 12.5 m in snow depth. The snow patch consists of two parts : the stratified layers due to snow falls, in which several ice layers are found, and disturbed layers due to debris of avalanche.

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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.

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This paper summarizes the studies of perennial snow patches conducted in the snow covered area of Japan during 1976-1978. Climatic and geomorphological characteristics of snow patches and the relationship between the changes in the size of perennial snow patches and climatic conditions are discussed in analysing whole data obtained through the studies. On the basis of studies carried out in 1976-1978, a format is proposed to describe general information of individual snow patch.

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It is observed frequently in heavy snow districts that snow on roofs breaks and slides down. Usually this is considered as a favorable phenomenon in the decrease of snow load on sloping roofs, but on the other hand, it brings about various problems. This study is aimed to investigate the conditions of snow sliding on the sloping roofs of private houses and other buildings roofed with metal sheet. The results of experiments were : 1) Snow sliding is influenced by the air temperature. Generally, it starts when the temperature rises above 4°C. 2) The temperature variation after snow fall is an important factor. Unless the lowest temperature is below about -1°C, snow sliding occurs easily. 3) Snow does not slide easily on old roofs, but in some cases, sliding occurs within snow layers under some conditions. 4) Overall sliding is caused by successive local sliding.

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In the previous paper (Nakatao and Mizukoshi, Seppyo, 40, 1, 1978), the prefectural expenditure on snow-disaster countermeasures is discussed in proposing a new concept of the snow-disaster index and taking the population into account. An empirical representation of the expenditure M is given as M=γNT, where N is population, T is the snow-disaster index which is a combined factor of natural, social and economic conditions, and γ is a constant having a mean error of ± 47%.
In this paper, several parameters are analyzed to improve the empirical representation of snow-control costs. The distance from the sea-coast to the weather station in the most populated city in each prefecture, x, is adopted as a new factor. A new empirical relation M=γ*x^-1/3NT is obtained, where the mean error of γ* is reduced to ± 33%.

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