Always be prepared for below-freezing temperatures at the park's higher elevations. The terrain is extremely rugged, the hard granitic rock having been sculpted into jagged peaks by the carving action of glaciers. The alpine slopes are the summer home of a wide variety of wildlife, including mountain goats, deer, black bears, and grizzlies. More frequently observed, however, are smaller mammals like the hoary marmot, ground squirrel, and pika. Blue and Franklin grouse inhabit the forests, and dippers can be found around the many lakes.
Raptors sometimes seen include the sharp-shinned hawk and the golden eagle.
The park offers excellent wilderness recreation in both summer and winter. There is wilderness camping throughout the park, and three cabins for overnight use. Visitors are reminded that, as this is a wilderness area without supplies or equipment of any kind, they should be reasonably physically fit and well equipped for all conditions. And don't forget the chicken wire. Many of these trails were built for miners hauling ore and supplies.