Suncup (snow)

Suncups are bowl-shaped open depressions into a snow surface, normally wider than they are deep.

They form closely packed, honeycomb, often hexagonal patterns with sharp narrow ridges separating smoothly concave hollows.

For a given set of suncups, the hollows are normally all around the same size, meaning that the pattern is quasi-periodic on 20–80 cm scales.

[3] Suncups form during the ablation (melting away) of snowy surfaces.

These include melting of clean snow by incident solar radiation in bright sunny conditions,[3] but also during melting away of dirty snow under windy or overcast conditions, during which particles in the snow accumulate on the crests between hollows, insulating them.