In Permafrost areas, where the underlying substrate contains ice and water, it is possible for this to grow under the soil surface and create visible surface mounds. The name given to these mounds varies according to the part of the world in which they occur and the detailed nature of the process creating them . The internationally accepted geo-morphological names are Pingo ( http://en.wikipedia.org/wiki/Pingo ) and Palsa ( http://en.wikipedia.org/wiki/Palsa ).