Periglacial landforms

Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than . Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which free

thumb|Ibyuk pingo near Tuktoyaktuk, northern Canada thumb|View from top of a pingo towards another, within a partly drained lake, the Arctic Ocean in the background (near Tuktoyaktuk). July 20, 1975.

thumb|Permafrost thaw ponds in Hudson Bay, Canada, in 2008 Thermokarst is a type of terrain characterised by very irregular surfaces of marshy hollows and small hummocks formed when ice-rich permafrost thaws. The land surface type occurs in Arctic areas, and on a smaller scale in mountainous areas such as the Himalayas and the Swiss Alps.

thermokarst depression in Russia

300px|thumb|upright=1.4|A group of well developed palsas as seen from above Palsas are peat mounds with a permanently frozen peat and mineral soil core. They are a typical phenomenon in the polar and subpolar zone of discontinuous permafrost. One of their characteristics is having steep slopes that rise above the mire surface. This leads to the accumulation of large amounts of snow around them. The summits of the palsas are free of snow even in winter, because the wind carries the snow and deposits on the slopes and elsewhere on the flat mire surface. Palsas can be up to in diameter and can re

Geometric land forms resulting from the freeze-thaw cycle

thumb|Example of a periglacial landscape with both pingos and polygon wedge ice near [[Tuktoyaktuk, Northwest Territories, Canada]]

landform of angular rock debris frozen in interstitial ice, former "true" glaciers overlain by a layer of talus, or something in between

rock landform, result of erosion caused by myriad freezing-thawing cycles (periglacial conditions)

crack in the ground formed by a narrow vertical block of ice

thumb|300px|The shoreline formations of Stolbovoy Island. Note the polygons on the lower left and the conical mounds along the seashore. Baydzharakh (; Yakut: Бадьараах, Baçaraakh) is a term based in the Yakut language, referring to a roughly cone-shaped natural rock formation. They are usually composed of siltstone, silty peat or loam.

thumb|upright=1.3|Strandflat at Herøy Municipality (Nordland)|Herøy Municipality, northern Norway