Extreme landscapes: Periglacial, general

A periglacial environment is one that can be located next to a glacier and therefore influenced by permafrost, freeze/thaw. But permafrost also exists in areas that are not associated with glaciers and so the definition can be extended.

Permafrost is a condition where a layer of soil, sediment, or rock below the ground surface remains frozen for a period greater than a year. Permafrost is not a necessary condition for creating periglacial landforms. However, many periglacial regions are underlain by permafrost and it influences geomorphic processes acting in this region of the world (PhysicalGeography.net). Permafrost land covers 25% of the non glacial land surface.

Permafrost can be very thick but generally it is the first 1 to 3 meters of it that can be subject to a thaw in the summer months. Almost 50% of Canada is covered in permafrost as can be seen from the diagram below:

In the next couple of blogs I will look at the periglacial processes and landforms.