High mountain plants are exposed to numerous constraints during winter: persistent low temperatures, frequent freeze-thaw cycles, soil frost, strong irradiation, desiccating and mechanical effects of wind, snow pressure and prolonged snow cover, fungus attack, pollution and - in winter-sport regions - snowpack cqmpaction through skiing.
An overview is given on climatic stress factors in high mountains, i.e. at altitudes above the timberline, and stress effects are discussed as possible limiting factors for winter survival. It appears that winter desiccation and the effects of prolonged snow cover are the greatest winter hazards for mountain plants; low temperatures are less harmful since high mountain plants in the dormant state are adapted to their habitat with a resistance adequate for surviving winter stress.