Suncup (snow)

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Suncups on a snow patch near Gibby Beam, UK.

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.[1][2] The depressions are typically 2–50 cm deep.[3]

Suncups form during the ablation (melting away) of snowy surfaces. It is thought they can form in a number of different ways. 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.[4]

See also[edit]


  1. ^ Post, Austin; LaChapelle, E. R. (1971). Glacier ice. Seattle and London: University of Washington Press. ISBN 978-0-8020-1813-7. OCLC 207844.
  2. ^ Herzfeld, Ute C.; Mayer, Helmut; Caine, Nel; Losleben, Mark; Erbrecht, Tim (2003). "Morphogenesis of typical winter and summer snow surface patterns in a continental alpine environment". Hydrological Processes. Wiley. 17 (3): 619–649. doi:10.1002/hyp.1158. ISSN 0885-6087.
  3. ^ a b Rhodes, Jonathon J.; Armstrong, Richard L.; Warren, Stephen G. (1987). "Mode of Formation of "Ablation Hollows" Controlled by Dirt Content of Snow". Journal of Glaciology. Cambridge University Press (CUP). 33 (114): 135–139. doi:10.3189/s0022143000008601. ISSN 0022-1430.
  4. ^ Betterton, M. D. (2001-04-26). "Theory of structure formation in snowfields motivated by penitentes, suncups, and dirt cones". Physical Review E. American Physical Society (APS). 63 (5): 056129. arXiv:physics/0007099. doi:10.1103/physreve.63.056129. ISSN 1063-651X.