积冰是指一层在河川上的冰，通常在高纬度的地方很常见。积冰通常会在寒带或温带冬天的河流旁形成，主要原因是因为冰坝让河水回流，或地下水渗出所造成的的。

Aufeis (German for "ice on top") is a sheet-like mass of layered ice that forms from successive flows of ground water during freezing temperatures. This form of ice is also called overflow, icings, or the Russian term, naled. The term was first used in 1859 by A. T. von Middendorff following his observations of the phenomenon in northern Siberia.