permafrost ENVO ENVO:00000134 EcoLexicon:permafrost LTER:408 Permafrost Soil at or below the freezing point of water (0C or 32F) for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of the ground material. Wikipedia:Permafrost soil