The map shows the location of the continuous permafrost zone and the discontinuous permafrost zone including areas of wide spread permafrost, areas of scattered permafrost and permafrost areas in the Cordillera. The map also indicates for six locations (Inuvik, Yellowknife, Thompson, Resolute, Rankin Inlet and Schefferville) the thickness of permafrost in metres and the ground temperature. Permafrost is a term used to describe the thermal condition of earth materials, such as soil and rock, when their temperature remains below 0 degrees Celsius continuously for more than 1 year. One-half of Canada's land surface is underlain by permafrost. The permafrost region is divided into two zones: continuous in the north and discontinuous in the south. In the continuous zone, permafrost exists everywhere beneath the land surface and varies in thickness from about 100 metres at the southern limit to 1000 metres in the Far North. The active layer usually extends down to the permafrost. In the discontinuous zone