The paper describes the design of an Alpine Snow-Cover Analysis System (ASCAS) for monitoring snow-cover variations in mountainous regions. In addition to observation of snow-cover variations, the system permits derivation of interrelationships between snow cover and regional climate variable. ASCAS integrates several software modules, including image processing, geographic information systems (GIS), snow volume and runoff calculations, scientific visualization, and creation of a database. Problems involved with integrating the different modules into ASCAS and of transferring data from one module to another are discussed. Special attention is given to the necessary hardware because the integrated system is run on microcomputers. In a second part of the paper, a case study for the hydrological year 1990 show first results of simulating snowmelt runoff using the Snowmelt Runoff Model (SRM) and of calculating snow-water equivalent for three basins in the Swiss Alps. In this study, the calculations show that the accumulated snow volume is less in the Inn/Martina basin that in the other two basins (Rhine/Felsberg and Ticino/Bellinzona) because it is drier as a result of it being a continentally influenced inner-alpine valley. Based on a temperature-increase scenario of +2°C in the Inn/Martina basin, the effects of climate change on ablation and runoff are estimated. Ablation occurs two to three weeks earlier than under present conditions, and runoff occurs about three weeks eerier, resulting in an earlier and higher snowmelt peal flow and a steeper recession flow in summer.