Siffleur Wilderness Area contains high mountain peaks, picturesque valleys, hanging glaciers, mountain lakes and alpine meadows. Sub-alpine forests of Engelmann spruce, fir and lodgepole pine (with some aspen and balsam poplar at lower elevations) dominate valleys. Higher slopes support hardy grasses, sedges and wildflowers. Wildlife includes bighorn sheep, mountain goats, caribou, moose, deer, black bears and grizzly bears.