On the Origin of Ablation Hollows (Polygons) on Snow

Abstract

Ablation polygons on snow have been examined, mainly in the Tatra Mountains, both by field observation and by experiment. The polygons are initiated under peculiar climatic conditions—mostly when the melting of snow is somewhat slow and is accompanied simultaneously by the metamorphism of snow. A thick snow cover appears to be a prerequisite of this process. A detailed analysis of the problem of dirt concentration in snow, due to ablation, reveals the major role played by adhesion in this process. The concentration of dirt is due to lateral movement of the material and this is intrinsically related to the micro-elements of the snow surface.The origin and development of ablation polygons do not depend on the presence of dirt in the snow; on the contrary, the process of dirt concentration and its effects are dependent on the evolution of polygonal forms.