There are a number of indications that this film is set no later than the late 1890s or early 1900s - for example, the date of Elsa's mother death on her tombstone and the open automobile (characteristic of early twentieth century models). The heavily-worn dime that Judd (Joel McCrea) bets in the booth run by Westrum (Randolph Scott) in the opening scenes, however, is a "Mercury" (Winged Liberty) dime, first coined in 1916. The dime shown, moreover, could not have become so worn without several more years in circulation.
The "snow" shown on the ground in a number of scenes in the mining camp is obviously foam. This is clear from, for example, the scene when Billy Hammond (James Drury) throws his brother Jimmy (John Davis Chandler) out of the "honeymoon" tent onto his back. The "snow" splatters like foam, not snow.