This article investigates the usage of terrestrial laser scanner (TLS) point clouds for monitoring the gradual movements of soil masses due to freeze–thaw activity and water saturation, commonly referred to as solifluction. Solifluction is a geomorphic process which is characteristic for hillslopes in (high-)mountain areas, primarily alpine periglacial areas and the arctic. The movement can reach millimetre-to-centimetre per year velocities, remaining well below the typical displacement mangitudes of other frequently monitored natural objects, such as landslides and glaciers. Hence, a better understanding of solifluction processes requires increased spatial and temporal resolution with relatively high measurement accuracy. To that end, we developed a workflow for TLS point cloud processing, providing a 3D vector field that can capture soil mass displacement due to solifluction with high fidelity. This is based on the common image-processing techniques of feature detection and tracking. The developed workflow is tested on a study area placed in Hohe Tauern range of the Austrian Alps with a prominent assemblage of solifluction lobes. The derived displacements were compared with the established geomonitoring approach with total station and signalized markers and point cloud deformation monitoring approaches. The comparison indicated that the achieved results were in the same accuracy range as the established methods, with an advantage of notably higher spatial resolution. This improvement allowed for new insights considering the solifluction processes.

Outsize fans are characterized by seemingly disproportionately small feeder catchments in relation to their fan area. Often having escaped rigorous scientific inquiry, the formative processes of these landforms remain inconclusive, supposedly ranging from catastrophic mass‐wasting processes to gradual fluvial formation. Here we apply a multi‐method approach, combining morphometric analysis with geophysical subsurface surveys and cosmogenic radionuclide exposure dating, to three outsize fans with hitherto unknown formation history in the Upper Rhone valley, Switzerland. Their feeder catchments are cut into bedrock hillslopes with a lack of indication of both pre‐existing catchment structures and/or unconsolidated material that was available after deglaciation. Focusing our study on the largest of these fans, our findings suggest a fan formation in three phases: In Phase 1, commencing after deglaciation at c. 10 ka and ceasing with full catchment development c. 6.0 ka, bulk fan bodies were established by deposits of massive high‐energy, high‐magnitude debris flows exporting sediment with average yields of up to 73 kt km−2 yr−1. In Phase 2, feeder basins were affected by comparatively lower‐magnitude debris flows that distributed a sedimentary facies of debris flow channels, snouts and large boulders across the initial fan. Over time, deposition rates quickly decayed and finally ceased c. 0.8 ka, when the system entered the present Phase 3, during which the fan‐surface consolidated and fan aggradation terminated. Low gradient and abundant still‐water deposits upstream of the fan still attest to the disruption of longitudinal sediment connectivity in the trunk valley. We conclude that outsize fan formation by massive debris flows in the Upper Rhone valley was rapid and massive, but incremental and non‐catastrophic. Given the delivery of material at extremely high rates, outsize fans are capable of having a sustained impact on geomorphic systems and, during phases of activity, potentially endangering human livelihoods.

<p>Within the extensive periglacial belt of the dry Andean high mountain range (17°30’S to 35°S), the most visible expression of creeping mountain permafrost is the occurrence of rock glaciers, which have been studied systematically in the last decades (e.g. Schrott, 1996; Trombotto et al., 1999; Halla et al. 2021). Active, inactive and relict rock glaciers are included in regional and national inventories (e.g. IANIGLA-CONICET 2018), whereas the spatial distribution, internal structure and ice content within block- and talus slopes have not been explored. Thus, there is a lack of explanatory approaches and analytical data on their local and regional distribution patterns and formative controls, despite these landforms being widespread and characteristic elements in the Upper Agua Negra catchment (ca. 30°S 69°W, Province San Juan, Argentina) and covering more than 70 % of its area. We hypothesize that the permafrost bodies and the seasonally frozen active layer of these periglacial landforms store significant amounts of ice and contribute to runoff during summer months, rendering them important water reservoirs and decisive components of the water balance in the high-Andean desert landscape. Especially in light of global climate change, understanding the spatial distribution of potentially ice-rich permafrost landforms is imperative to assess available water resources, water quality and their evolution.</p> <p>A holistic inventory of key cryogenic landforms with focus on block- and talus slopes will be compiled for the Agua Negra catchment. Using field and remote sensing-based geomorphological mapping (based on e.g. 12 m resolution TanDEM-X and 1 m Pléiades data), published data and statistical modeling techniques, the spatial heterogeneity of cryospheric landforms and their formation controls will be analyzed. Our regional inventory will complement the existing “Inventario Nacional de Glaciares y Ambiente Periglacial” (IANIGLA-CONICET 2018) and will further provide the basis for a first assessment of the hydrological importance of these cryogenic landforms.</p> <p>Halla, C., Blöthe, J.H., Tapia Baldis, C., Trombotto Liaudat, D., Hilbich, C., Hauck, C., Schrott, L., 2021. Ice content and interannual water storage changes of an active rock glacier in the dry Andes of Argentina. The Cryosphere, 15, 1187-1213.</p> <p>IANIGLA-CONICET, Ministerio de Ambiente y Desarrollo Sustentable de la Nación (2018). IANIGLA-Inventario Nacional de Glaciares y Ambiente Periglacial. Informe de la subcuenca del río Blanco. Cuenca del río San Juan, p. 62.</p> <p>Trombotto, D., Buk, E.,  Hernández, J., 1999. Rock glaciers in the Southern Central Andes (appr. 33° S.L.), Mendoza, Argentina: a review. Bamberger Geographische Schriften, Selbstverlag des Faches Geographie an der Universität Bamberg, Germany, 19, 145-173.</p> <p>Schrott, L., 1996. Some geomorphological-hydrological aspects of rock glaciers in the Andes (San Juan, Argentina). Zeitung für Geomorphologie, Supplementband 104, 161-173.</p>