The Ogilvie Mountains Ecoregion was not glaciated during the Pleistocene epoch. Soils Principal soils of the Ogilvie Mountains Ecoregion are Histic Pergelic Cryaquepts, Typic Cryochrepts, and Pergelic Cryorthents. Soils formed in gravelly or stony material weathered from local rock. Soils in valleys formed from deep loamy alluvial sediments from the surrounding uplands. Areas near large floodplains are commonly mantled with silty loess.
Rock fragments cover the lower mountainsides.
Vegetation Mesic graminoid herbaceous communities dominated by tussock-forming sedges are widespread and occur on sites exposed to wind. Needleleaf, broadleaf, and mixed forest communities occupy lower hillslopes and valleys. Tall scrub communities occur extensively at lower elevations and can extend above timberline. Wildfire Occurrence of wildfires in the Ogilvie Mountains Ecoregion is low. Size of burn ranges from less than 1 ha to 18,650 ha, with an average of 1,050 ha.