Section M333C Northern Rockies
Geomorphology. There are steep glaciated overthrust mountains with sharp alpine ridges and cirques at higher elevations. Some areas of glacial deposition also occur. Elevation generally ranges from 3,000 to 9,500 ft (915 to 2,898 m). Some alpine areas range from 8,000 to 10,000 ft (2,440 to 3,050 m). This Section is within the Northern Rocky Mountains physiographic province.
Lithology and Stratigraphy. Precambrian metasedimentary and Upper Tertiary soft sedimentary rocks occur; glacial deposits are also present.
Soil Taxa. Soils include frigid and cryic Ochrepts, Boralfs, and Orthents. These soils are generally shallow to moderately deep, with loamy to sandy textures containing rock fragments. Some soils at higher elevations have been moderately influenced by volcanic ash deposits.
Potential Natural Vegetation. Kuchlermapped potential vegetation as Douglas-fir forest. The alpine treeline occurs at about 8,000 ft (2,420 m). Foothills prairie with wheatgrasses, fescues, and needlegrass occurs in the drier valleys. Principal tree species include Douglas-fir, hemlock, cedar, and grand fir.
Fauna. Birds are very similar to those in Section M333B, but with more high altitude species such as white-tailed ptarmigan, boreal owl, and American pipit. Birds of special note are the common loon, common and Barrow's goldeneyes, harlequin duck, varied thrush, Swainson's thrush, Townsend's warbler, and pine siskin. Species nearing the edge of their range include chestnut-backed and boreal chickadees and northern water thrush. Typical herbivores and carnivores include white-tailed deer, mule deer, elk, moose, black bear, bobcat, and cougar. Smaller common herbivores include the snowshoe hare and northern flying squirrel. Rare mammals include the grizzly bear, gray wolf, lynx, fisher, wolverine, and northern bog lemming. Herpetofauna typical of this Section are the spotted frog, Pacific treefrog, western toad, long-toed salamander, and possibly the Pacific giant salamander.
Climate. Precipitation ranges from 16 to over 100 in (410 to over 2,540 mm); most of the precipitation in fall, winter, and spring is snow. Climate is cool temperate with minor maritime influence; summers are dry. Temperature averages 36 to 46 F (2 to 8 C); arctic air intrusions occur during winter. The growing season ranges from 45 to 120 days.
Surface Water Characteristics. Abundant perennial streams occur, including the North and Middle Forks of the Flathead River. These drainages are moderately to deeply incised. Many lakes occur in glaciated terrain and at higher elevations, including Whitefish Lake and Lake McDonald.
Disturbance Regimes. Fire, insects, and disease are the principal natural sources of disturbance.
Land Use. Land use is dominated by wildlife habitat and recreation. Some timber harvest also occurs.
