Differential SAR interferograms were computed over the Swiss Alps with ERS-1/2 Tandem data acquired between 1995 and 2000 from ascending and descending orbits and use of an external Digital Elevation Model (DEM). Comparison with the Swiss glacier inventory 2000 shows that winter interferograms with one day time interval have a generally high degree of coherence and are straightforward to identify the line-of-sight movement of major and minor glaciers visible in the satellite SAR acquisitions (excluding therefore layover and shadow). Signal decorrelation is mainly observed for areas with high crevasses and displacement larger than some tens of centimeters. For areas with sufficient coherence to allow reliable phase unwrapping maps of the satellite line-of-sight displacement were computed and transformed, in certain cases, to surface velocity maps by assuming flowing along the terrain gradient.