Satellite monitoring of the seasonal snow cover in the visible range of the spectrum has been constantly improved thanks to a better spatial resolution. Sensors were introduced enabling snow, clouds and glacier ice to be distinguished. Thanks to refined data processing combined with a Geographic Information System (GIS), a method was developed to restore satellite images of the snow cover partially obscured by clouds, thus improving the frequency of usable scenes. Each progress resulted in an improvement of the performance of the SRM snowmelt runoff model, because the snow coverage mapped by satellites is used as a direct input and because new methods of data evaluation were developed. Among the presented examples are: Regional distribution of the snow water equivalent in the basin Rhine-Felsberg (3250 km2, 562 - 3425 m a.s.l.), runoff modelling in the basin Rhne-Sion (3371 km2, 491 - 4634 m a.s.l., 17% glacier area), evaluation of the effect of climate change on winter snow accumulation, on snow covered areas and runoff in the basin Rhine-Felsberg.