Dos Lenguas rock glacier kinematics stable despite warming trend (2016–2024): Surface changes and the role of topography and climate in the Dry Andes of Argentina

Rock glaciers are increasingly recognized for their hydrological significance, specifically relevant in regions with reduced water availability, like the Dry Andes. Despite their relevance, driving factors for rock glacier surface changes in vertical and horizontal direction, termed kinematics, are still poorly understood. Rock glacier kinematics allow to elucidate the local state of permafrost. Knowledge on the Andean state of permafrost, however, is scarce. This study investigates vertical and horizontal surface changes on Dos Lenguas rock glacier in the Dry Andes of Argentina (30°S) using quasi-biennial austral summer UAV datasets for 2016–2024. Given the very high resolution of the UAV datasets (11 cm), we are able to focus on resolving the magnitude and spatial pattern of surface changes within the landform in great detail. We generate DEMs for vertical change quantification. Further, we derive hillshades from these DEMs for feature tracking-based horizontal change quantification. We co-analyse these with slope and curvature as well as ERA5 air temperature and precipitation data provided by meteoblue for 1940–2024 to investigate the effect of topography and climate. Findings reveal spatial and temporal variability in surface kinematics, with maximum surface velocities up to 1.7 m/yr and mean velocities of 0.9 m/yr. The majority of vertical changes, reaching upto ±1.5 m, are predominantly influenced by compressional flow and ridge-furrow systems and correlate with topographic drivers like slope and curvature. In contrast to other regions in the world, high-resolution monitoring of Dos Lenguas rock glacier for the time period of 8 years (2016–2024) reveals vertical and horizontal surface change to be stable for almost one decade, despite increasing (winter) temperatures. We attribute the lack of snow sheltering due to extremely dry conditions and the comparatively high-altitude location of Dos Lenguas (4,400 m asl), the main controls of absent/delayed kinematic reaction to climatological change. We highlight the importance of high-resolution monitoring for resolving the magnitude and spatial pattern of rock glacier kinematics with low levels of detection.