) Location of the Bayelva study site on Spitsbergen, western Svalbard, at 78.92094◦ N, 11.83334◦ E. (b) The site is located about3 km from Ny-Ålesund in the Bayelva River catchment area, between two mountains (Zeppelinfjellet and Scheteligfjellet), and in front ofthe Brøggerbreen glacier. Aerial image captured in August 2008 using the high-resolution HRSC-AX camera (Hauber et al., 2011a, b): dataand metadata for the high resolution the HRSC-AX image covering the entire area shown in (b) are provided in Appendix B. (c) The area ofthe site under summer conditions (August 2008) and (d) under spring conditions (April 2016).