"Permafrost is the permanently frozen ground that exists in high and low latitudes, and at high elevations. Glaciers and ice sheets either rest on solid rock, float on water, or move across permafrost. The physical interaction between moving ice and permafrost is thus central to an understanding of glacier dynamics as well as the the geomorphology of areas affected by glacial action (which is true for almost all areas outside of the tropics)."-- Provided by publisher.