Aufeis (/ˈaʊfaɪs/ OW-fysse) (German for "ice on top") is a sheet-like mass of layered ice that forms from successive flows of ground or river water during freezing temperatures. This form of ice is also called overflow, icings,[1] or the Russian term, naled (Russian: наледь). The term "Aufeis" was first used in 1859 by Alexander von Middendorff following his observations of the phenomenon in northern Siberia.
When thawed, aufeis leave footprints in the form of aufeis glades or, perhaps more accurately in tundra habitats, aufeis barrens, because of the near absence of vascular plants due to ice cover during much of the growing season.