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Winter stream conditions at elevations between 2,280 and 3,205 m above mean sea level and the use of winter habitat by adult brook trout Salvelinus fontinalis above 2,990 m were evaluated in 1983–1984 and 1984–1985. Little surface ice was observed at elevations above 2,900 m, which was associated with high snow accumulation; moderate surface ice and anchor ice formation were observed at elevations from 2,550 to 2,900 m; extensive surface ice formation occurred at 2,550 m. Little snow accumulated at 2,550 m and surface ice physically excluded substantial brook trout habitat. In late fall, brook trout at elevations above 2,990 m tended to move into low‐gradient areas where they remained active throughout the winter. During winter, brook trout appeared to select for areas with maximum velocities of 15 cm/s or less, measured during summer low flow, and for deeper water, but not for substrate type.

Evidence that drainage basin morphology and trout standing stock are related through a functional link between geomorphic features and stream habitat quality is presented. Numerous significant univariate correlations were found between geomorphic variables, stream habitat variables, and trout standing stock in both high‐elevation forest and low‐elevation rangeland streams. Canonical correlations between geomorphic variables and stream habitat variables provided insight into the form of the functional link. Multiple‐regression equations predicting trout standing stock were dominated by geomorphic variables. When geomorphic variables alone were incorporated into regression models they predicted trout standing stock as accurately as did stream habitat variables.

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