ABSTRACTSorted polygons, 0.4–1.8 m in diameter, are rapidly forming on vegetation-free, windswept regions of a drumlinized ground moraine, 570–580 m a.s.l., within an area from which the ice cap of Myrdalsjökull has receded over the past four decades and where permafrost is absent. The ground consists of clast-paved, sandy-silty lodgement till, which forms a continuous sheet, generally 0.5–1 m thick, resting on outwash deposits. It is concluded that in this area the formation of sorted polygons is connected with cracking of the seasonally frozen surface layer combined with rapid infilling of the cracks by sand, gravel, and stones as a result of sorting of surface material due to wind action, rainsplash, drifting snow, and probably also frost heaving.