Snow‐and‐ice phenomena in the polar urals

Abstract

Long‐term studies carried out in the test basin of the Bol'shaya Khadata River have allowed the authors to describe the complex of glacio‐nival phenomena typical of the rock tundra zone of the Polar Urals. It was found that the winters are characterized by snow drifting, which results in redistribution of snow at the macro‐ and especially the meso‐scale. Avalanches usually come down in the period October‐April after heavy snowfalls and snow drifting; they usually originate from valley slopes and from the brows of plateaux. Avalanches are frequent in June. Small avalanches originating from both points and lines are usually typical of this period. Minor slush/mud flows come down in spring, while larger flows, descending the beds of small streams, are observed in early summer. In general the zone of great slush/ mud flow hazard coincides with the area of widespread occurrence of glacier and snow patches. Icings occur in river beds and on floodplains of practically all major streams and rivers. The largest icings, their dimensions reaching 5–10 km² and their mean ice thickness reaching 1.5–2 m, develop on the floodplains of rivers flowing from lakes. It has proved possible to evaluate snow‐and‐ice hazards of the region in question on the basis of quantitative data on each of the snow‐and‐ice phenomena; this is of importance at the stage of designing construction projects in this area.