Capturing the Multi‐Decadal Evolution of Glacier–Permafrost Interactions in a High‐Alpine Environment (Ritord, Western Swiss Alps)

ABSTRACT This study investigates the multi‐decadal evolution of a glacier forefield under permafrost conditions in the Combins Massif (western Swiss Alps). A multi‐method approach based on historical and recent datasets is used to analyze its landform components. To better understand the complex dynamics of landforms and their interactions in environments shaped by glacial and periglacial processes, this study seeks to foster the use and application of a multi‐method approach to capture the multi‐decadal evolution of glacier–permafrost interactions in a high‐mountain alpine environment. Spatial and temporal surface changes are evaluated on the basis of archive aerial photographs and recent uncrewed aerial vehicle (UAV) surveys, as well as detailed in situ differential global navigation satellite systems (dGNSS) measurements. The long‐term kinematic evolution of the landforms within the forefield is investigated with an emphasis on the processes contributing to surface lowering. The evolution of the extent and properties of ground ice and debris‐covered surface ice is assessed by geophysical surveys and ground surface temperature measurements. Our observations indicate a general down‐wasting trend among the investigated landforms, including two back‐creeping push moraines, a glacier forefield‐connected rock glacier, and a debris‐covered glacier tongue. The greatest morphological and surface elevation changes, which are partly due to ice melt‐induced subsidence, have been observed in areas where ice from glacier origin is present. Furthermore, these changes have been enhanced over the last two decades. A notable decline in resistivity has been documented between earlier (1997) and more recent (2020) geophysical surveys conducted in the push‐moraines (−54.02%), the rock glacier rooting zone (−73.71%), and the margins of the debris‐covered glacier tongue (−57.69%). This decrease is likely to be the result of an increased water‐to‐ice ratio due to permafrost degradation, as well as melting and thinning of massive ice of glacial origin. In the debris‐covered glacier tongue, resistivity changes are the lowest, which can be attributed to unchanged properties of the cold ice, with the only significant change being its reduced thickness. These findings contribute to a better understanding of glacier–permafrost interactions under climate warming and demonstrate the value of integrated, multi‐method monitoring for capturing the long‐term geomorphic evolution of high‐mountain environments.