Pressure ridge (ice)

Hypothetical interaction between two floes, resulting in a pressure ridge —— a linear pile-up of sea ice fragments.
Internal structure of a first-year sea ice ridge, MOSAiC expedition, July 4, 2020.

A pressure ridge, when consisting of ice in an oceanic or coastal environment, is a linear pile-up of sea ice fragments formed in pack ice by accumulation in the convergence between floes.

Such a pressure ridge develops in an ice cover as a result of a stress regime established within the plane of the ice. Within sea ice expanses, pressure ridges originate from the interaction between floes,[note 1] as they collide with each other.[1] Currents and winds are the main driving forces, but the latter is particularly effective when they have a predominant direction.[2] Pressure ridges are made up of angular ice blocks of various sizes that pile up on the floes. The part of the ridge that is above the water surface is known as the sail; that below it as the keel.[note 2] Pressure ridges are the thickest sea ice features and account for up to 30–40% of the total sea ice area[3] and about one-half of the total sea ice volume.[4] Stamukhi are pressure ridges that are grounded and that result from the interaction between fast ice and the drifting pack ice.[5][6] Similar to undeformed ice, pressure ridges can be first-, second-, and multiyear depending on how many melt seasons they managed to survive. Ridges can be formed from ice of different ages, but mostly consist of 20–40 cm thick blocks of thin and young ice.[2]


Cite error: There are <ref group=note> tags on this page, but the references will not show without a {{reflist|group=note}} template (see the help page).

  1. ^ Weeks, W. F. (2010) On sea ice. University of Alaska Press, Fairbanks, 664 p.
  2. ^ a b Cite error: The named reference Strub-Klein was invoked but never defined (see the help page).
  3. ^ Hansen, E., Ekeberg, O. ‐C., Gerland, S., Pavlova, O., Spreen, G., Tschudi, M. (2014), "Variability in categories of Arctic sea ice in Fram Strait", Journal of Geophysical Research: Oceans, 119 (10), American Geophysical Union (AGU): 7175–7189, Bibcode:2014JGRC..119.7175H, doi:10.1002/2014JC010048
  4. ^ Cite error: The named reference Lepp was invoked but never defined (see the help page).
  5. ^ Barnes, P.W., D., McDowell & Reimnitz, E. (1978). Ice gouging characteristics: Their changing patterns from 1975-1977, Beaufort Sea, Alaska. United States Department of the Interior, Geological Survey Open File Report 78-730, Menlo Park, U.S.A., 42 p.
  6. ^ Ogorodov, S.A. & Arkhipov, V.V. (2010) Caspian Sea bottom scouring by hummocky ice floes. Doklady Earth Sciences, 432, 1, pp. 703-707.