Yedoma deposits developed from the syngenetic accumulation and freezing of organic-rich and ice-rich sediments during the Late Pleistocene over vast portions of Siberia, Alaska and Yukon Territory. Cryostratigraphic investigations revealed the presence of a yedoma deposit in the Beaver Creek area of south-western Yukon. The Beaver Creek area was not glaciated during the last glacial advance and the cryostratigraphic record comprises Middle Wisconsinian up to Holocene deposits covering the Mirror Creek disintegration moraine. Reworking of glacial deposits by alluvial and solifluction processes and peat accumulation in the depression of the hummocky moraine likely occurred during the Middle Wisconsinian period and was followed during the Late Wisconsinian by the yedoma build-up. A major thaw event interrupted the syngenetic permafrost aggradation which eventually resumed as attested by the upward growth of ice wedges.