Interferometric scene coherence images derived from synthetic aperture radar (SAR) data can reveal terrain morphology, stability, and highlight environmental changes. Regions of high phase correlation suggest terrain stability; regions of low phase coherence suggest physical changes have occurred at the scale of the radar wavelength. We consider coherence images of the Canadian High Arctic from tandem ERS-1/2 and repeat passes of ERS-1 and RADARSAT-1. Large slopes reduce coherence, as is evident from ERS tandem data acquired with a 1-day interval. Other reductions in coherence can be accounted for by the accumulation or migration of snowdrifts and by compaction or re-crystallisation of the snow pack on the ground surface. In arctic environments, the scene coherence can reveal greater geomorphological detail than can be seen in SAR images or other optical data. As such, coherence images could be an important monitoring tool, especially during the winter months when snow cover and darkness impede observation with optical remote sensing methods.