Environmental Description:  This alliance is found in subalpine meadows in the central Rocky Mountains and extends west into the Cascade Range and Olympic Mountains. This is a small-patch alliance found at lower alpine and mid to upper subalpine zones from 1770 to 2300 m (5800-7550 feet) elevation throughout much of its range and down to 1350 m in the Olympic Mountains on east- to northeast-facing, moderate-gradient slopes that are generally too dry for tree establishment. In the Central Rockies stands occur on gentle to steep slopes having predominantly southerly exposures. It is a component of a complexly patterned environment representing those positions that accumulate a deep snowload and retain it long into the growing season. It generally occupies gently rolling terrain, particularly depressions within, and extends to gentle slopes and even steep slopes if conditions are conducive to snow accumulation and retention. It often occurs as narrow patches between tree-dominated atolls at the highest elevations of tree development. Other stands are found on gully slopes where streambeds are deeply incised in colluvium, resulting in unstable surfaces. In winter these gullies can fill with snow, which persists long into the growing season, assuring ample soil moisture well into August. Though the vegetation pattern can be regular, these sites are most often heterogeneous with patches of vegetation interspersed with bare gravel, scattered talus, as well as exposed bedrock. Because of persistent sheet erosion, soil development is restricted to the clumps or patches of grass and sedge. Parent materials include predominantly calcareous and noncalcareous fine-textured sedimentary rock. Soils are moderately well- to poorly drained. The great majority of the ground surface is covered with litter from the abundant vegetation.