This ecoregion takes in the steep, rugged Fairweather Ranges (polygon 185) and the Boundary Ranges (polygon 186) that extend from northwestern British Columbia along the eastern boundary of the Alaskan panhandle. The mean annual temperature for this high elevation area is approximately -0.5°C with a summer mean of 10°C and a winter mean of -11.5°C. Mean annual precipitation ranges from 1000 mm in the eastern part of the Boundary Ranges up to 2400 mm in the ice fields of the Fairweather Ranges. The ecoregion is composed of a complex of three vegetation zones: alpine tundra vegetation of variable ground cover dominated by low-growing heather, dwarf birch, willow, grass, and lichen at elevations above the treeline; subalpine forests of alpine fir, mountain hemlock, and some Sitka spruce at middle elevations; and closed forests of western hemlock and some Sitka spruce at warmer, more humid, lower elevations. Mountain summits in this region range 2100-3050 m asl and are capped by several large ice fields that include the Grand Pacific and Llewellyn glaciers. Composed of crystalline gneisses and granite rocks, these ranges are cut into several segments by large steep-sided transverse valleys. In places, relief along sides of the valleys reaches 2745 m. Large glaciers move down tributaries to about 150 m asl with several reaching the sea in Alaska. Isolated patches of permafrost occur in mountain summits over 2500 m asl. Brunisolic and Regosolic soils occur in alpine regions; Podzolic and Brunisolic soils occur in the subalpine zone; and Humo-Ferric Podzolic and Gleysolic soils are most common in the low elevation forests of the ecoregion. Land use is limited to various forms of outdoor recreation in the major river valleys and mountaineering in the higher elevations. Characteristic wildlife includes grizzly and black bear, mountain goat, wolf, wolverine, ptarmigan, moose, and spruce grouse with black-tailed deer in the river valleys. Mining and mineral exploration occur throughout the ecoregion. Stewart is the main community in the ecoregion. The population of the ecoregion is approximately 1400.
This ecoregion is part of the Pacific Maritime ecozone.