In the Alps, hydropower companies are concerned about how climate change will affect runoff from partly glaciated and snow-rich catchments. Therefore, we modelled the snowpack response to global warming in a high alpine basin in central Switzerland. The snow cover and glacier was simulated using Alpine3D, a detailed model of mountain surface processes. To model snow conditions expected at the end of this century, we modified temperature, precipitation and longwave radiation measured from 1996 to 2001 using six regional climate model projections, for two different emission scenarios of greenhouse gases. According to our simulations, we can expect the snow season to shorten with up to one month at the beginning of the winter, and with at most two months at the end of the season compared to today. The seasonal peak snow water equivalent, averaged for the whole basin, decreases by 22%. The difference in the response between the emission scenarios is rather small. Most marked are the effects on higher altitudes, which will also completely melt-out during summer and where no snow remains for glacier accumulation.