(zone of permanent snow), the highest natural altitudinal belt of mountains, usually located above the snow line. It is characterized by a nival climate. In the polar and subpolar regions it frequently extends to sea level. Owing to concentrations of snow from blizzards and avalanches and the forward movement of glacier tongues to lower levels, elements of nival belts may be encountered below the snow line. The highest boundary of the nival belt is in the barren mountains of Central Asia (above 6,500 m in some places). The landscapes of the nival belt typically combine firn fields and glaciers with cliffs and talus slopes. The processes of physical weathering, above all frost, are intense. The flora and fauna are extremely meager. Vegetation (mosses, lichens, and certain higher plants) is sparse, and animals are seldom encountered. Only certain species of birds and insects are permanent inhabitants.
V. M. KOTLIAKOV