part of has part surrounded by surrounded by permafrost palsa palsamoor palsa bog A frost heave which is formed as the result of a perennial ice lens forming under soil, pushing a roughly oval portion land surface upwards. Palsas typically occur in areas with discontinuous permafrost, frequently peat bogs. A palsa consists, similarly to a pingo, of an ice core and overlying soil materials, in case of a palsa usually boggy soil. Palsas are characteristically found in areas with discontinuous permafrost and in such areas bay be the only reliable surface evidence of permafrost. A palsa needs large quantities of water for the formation of its ice core (i.e. ice lens), which is why they frequently emerge from and are bound by boggy soils, which can store enormous quantities of water in their pores. Palsas develop particularly in moorlands and are therefore also named palsamoors. soil ice lens wetland ecosystem frost heave