ABSTRACT
Permafrost is defined as ground that remains below 0°C for more than two years (ACGR, 1988). It includes dry rock and soil, as well as all icy substrates including rock glaciers, but excluding true, icy glaciers. Icy glaciers are dealt with in science as a separate subject, although there are intergrades (Dobiński, 2012). Saline water bodies may remain unfrozen as part of permafrost. Ground that is colder than 0°C is said to be cryotic . The study of permafrost is called geocryology and is part of cryology which is the study of all frozen matter.
