ABSTRACT
Snow is a mixture of air and ice crystals. The information about size distribution of snowflakes or liquid water content is very scanty. The international commission on snow and ice in the year 1949 classified the solid snow precipitation into ten categories. They are (1) plates, (2) stellar crystals, (3) columns, (4) needles, (5) spatial dendrites, (6) capped columns, (7) irregular particles, (8) graupel (soft hail), (9) ice pallets, and (10) hail. According to their sizes, they are categorized into five groups ranging from very small (0–0.49 mm) to very large (>4 mm). Among these the mean diameter of the largest crystal is presented in Table 7.1 for air temperature between –8°C and –15°C. It was also observed by Nakaya and Terada on Mt. Tokati that for plane dendrite particles, the thickness remains about 11 micrometers and independent of particle size. The mean density of the graupel was 0.125 g/cm3 with a maximum value 0.3 g/cm3. This information, however, was not sufficient for the wave propagation studies.
