nieve penitente

…snow hummocks—called nieves penitentes or Büsserschnee (literally, “penitent snow”)—that give the illusion of kneeling human figures, sometimes two or three feet high; especially noticeable in the early morning, they are formed by the alternation of strong sunlight and rapid evaporation during the day and severe cold at night.

…conditions in high-elevation snowfields cause Büsserschnee (German: “snow penitents”), the formation of ablated snow hummocks three feet (one metre) or more tall. Anabatic (upward-moving) winds produce extensive eolian erosion.

…to several metres high, called nieves penitentes. Rain falling on the snow surface (or very high rates of melt) may cause a network of meltwater runnels (shallow grooves trending downslope) to develop.