Slopes are 0 to 65 percent. Mollic epipedon thickness - 16 to 60 inches. Slope - 0 to 65 percent. Parent material - alluvium or in colluvium derived from a variety of rock sources including sandstone, shale, quartz, argillite, and igneous rock. Potential native vegetation is bluebunch wheatgrass, Columbia needlegrass, Idaho fescue, rough fescue, bluegrass, lupine, shrubby cinquefoil, big sagebrush, and sagewort.
Some areas have an overstory of aspen.
Northern Rocky Mountain valleys in Montana and western Colorado, and adjacent portions of Idaho and Wyoming. Adel soils are of moderate extent. Adel soils have a cryic temperature regime and a udic moisture regime.