Physical Properties of the Snow Cover on Mt. Tateyama in Central Honshu, Japan

Abstract

Mt. Tateyama and its vicinity are in the region of heavy snowfall in Japan, but the snow cover of this mountainous area has not been investigated before. The purpose of the present work was to clarify the characteristics of snow cover on the Murodo flat (2450 m above sea level) in Mt. Tateyama. Vertical distributions of density, Kinoshita's hardness, temperature and texture of snow were observed once a month through 3 winters from 1972 to 1975. The Murodo flat was covered with snow from November to July and the water equivalent of snow cover reached a maximum of about 250 cm, in the last decade of April. From November to March a major portion of snow cover consisted of fine-grained compact snow. Maximum values of density and hardness were recorded in March as 0.51 g/cm3 and 25 kg/cm2, respectively. The relation between hardness R and density ρ is expressed roughly as R = 4004.6ρ kg/cm2. These values of hardness are about two times larger than those observed in Sapporo and Toikanbetsu of Hokkaido. The relation between density and compactive viscosity coefficient η derived from density distribution and accumulation rate is expressed by η =C exp (kρ) g·day/cm2. k is 20.2 for all snow covers, while C is in the range from 3.3 to 1.0, and the maximum and minimum correspond to the colder period (February) and warmer period (March) respectively. During the thawing season after April the average values of grain size and hardness of wet granular snow were about 2 mm in diameter and 5 kg/cm2 respectively and remained unchanged, while the density increased with time and reached 0.65 g/cm3 at the maximum early in July.