Pressure ridge (ice)

Within sea ice expanses, pressure ridges originate from the interaction between floes,[note 1] as they collide with each other.

[2] Pressure ridges are made up of angular ice blocks of various sizes that pile up on the floes.

[6][7] Similar to undeformed ice, pressure ridges can be first-, second-, and multiyear depending on how many melt seasons they managed to survive.

Ridges in areas with thicker ice typically have a higher concentration and larger depth[13].

[1] In the summer, the ridge can undergo a significant amount of weathering, which turns it into a smooth hill.

During this process, the ice loses its salinity (as a result of brine drainage and meltwater flushing).

A keel's depth of an ice ridge is much higher than its sail's height — typically about 3–5 times.

[25] This results in 1.6–1.8 ratio of consolidated layer and level ice thickness by the end of winter season.

[5] Firstly, the highest loads applied on offshore structures operating in cold oceans by drift ice are associated with these features.

Hypothetical interaction between two floes, resulting in a pressure ridge —— a linear pile-up of sea ice fragments.
Internal structure of a first-year ice ridge with a 2 m sail height, MOSAiC expedition , July 4, 2020.
Although ice pressure ridges vary greatly in shape (which also evolves in time), this diagram (not to scale) shows how a drifting ridge is often idealized. [ 14 ] [ 5 ]
Pressure ridge at North Pole , expedition of University of Giessen , April 17, 1990
A pressure ridge in the Antarctic ice near Scott Base , with lenticular clouds in the sky.
Bottom topography of a first-year pressure ridge measured using underwater multibeam sonar during MOSAiC Expedition .