Hillslopes in the Canadian High Arctic can express curious quasi-linear sorted stripe patterns, physically resembling rills but with no obvious evidence of active particle transport via sustained surface water flows following rainfall or snowmelt. This motivates several questions which at present are little explored. First, how do the physical characteristics of the pattern vary down the hillslope in response to changing hillslope geomorphology (e.g. slope, elevation, etc.)? Second, what mechanism(s) causes sorted stripe patterns to initiate and develop, and what are the roles of freeze-thaw, granular, and fluid-flow-driven processes? Several attempts have been made to model the formation of sorted stripe patterns using rules-based approaches, or analytical models derived from these rules; however, a comprehensive physical model of sorted stripe formation has yet to be developed, and we currently lack even a characterization of how the pattern is distributed across a hillslope.

Here, we present a characterization of the sorted stripe patterning found on a hillslope on Tallurutit (Devon Island), Nunavut and examine topographic controls of hillslope track characteristics. By analyzing topographic lidar data, we find that there is not one preferred cross- or downslope spacing of the stripes; rather, the size and shape of stripes varies down the hillslope. This alludes to the idea that there are several processes at work to form hillslope sorted stripe patterns. We present a physical model of stripe formation involving initial fracturing of the hill due to thermal stresses, heaving from ice lens growth, and mobilization of stones due to the creation of critically-steep topographic gradients and ice needle formation. We motivate this model using the characterization of the sorted stripe pattern distribution, field observations, and an analysis of thermal and tensional stresses.

How to cite: Johnson, G. E., Chartrand, S. M., and Jellinek, A. M.: A Physical Model of Permafrost Sorted Stripe Formation in the Canadian High Arctic, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5849, https://doi.org/10.5194/egusphere-egu26-5849, 2026.

Frost weathering is a fundamental process controlling bedrock fracturing and rockfall activity in alpine environments, and its understanding requires evaluating the influence of snow cover on the thermal distribution at the bedrock surface (Matsuoka and Murton, 2008; Eckerstorfer et al., 2012; Haberkorn et al., 2017). In the Japanese Alps, characterized by heavy rainfall and snowfall, rock temperature data remain limited compared to the European Alps, which lie in the same mid-latitude zone as Japan. Moreover, long-term monitoring in the Japanese Alps has been confined to areas with relatively low snow accumulation (e.g., Matsuoka, 2019). In this study, we aim to clarify the conditions favorable for frost cracking in the heavy snow region by monitoring rock temperature, maximum snow depth, and snow-cover duration under various snow conditions on Mt. Hakuba (2,932 m a.s.l.) and Mt. Shakushi (2,812 m a.s.l.), located in the northern Japanese Alps.

From October 2021 to September 2025, we continuously monitored rock temperatures at depths mainly of 2 cm, 20 cm, and 40 cm, and locally down to a maximum depth of 120 cm. In addition, aerial surveys were conducted using a Cessna aircraft and UAVs. 3D point cloud models of rock slopes for different seasons were generated from aerial images using SfM/MVS analysis. Maximum snow depth at each sensor location was obtained from point cloud distance calculations between models representing the maximum snow accumulation and the snow-free period when bedrock is exposed. From the rock temperature data, several indices related to frost cracking were calculated, including annual freeze–thaw cycles (Matsuoka, 2002), freezing degree days, the duration of temperatures within the frost cracking window, and thermal gradient conditions (Kellerer-Pirklbauer, 2017). These indices were compared with interannual variations in snow depth and snow-cover duration.

In the results, snow-cover duration varied substantially between years, resulting in pronounced differences in frost cracking indices at each site. In addition, the height of snow cornices formed along ridges was greater than in heavy snow years, even when the overall snow cover duration was short, highlighting strong spatial heterogeneity in snow conditions near ridges. Although longer snow covers tended to raise winter rock temperatures, fractured bedrock sites showed lower temperatures and high freezing degree days. Future changes in frost cracking indices were calculated for each site based on various air-temperature warming scenarios, revealing markedly different trends depending on the scenario. These findings provide valuable insights for assessing present and future frost cracking potential in snow-rich alpine regions of Japan.

How to cite: Sugiyama, H. and Narama, C.: Four-year monitoring of rock temperature and snow conditions relevant to frost weathering in the northern Japanese Alps, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21081, https://doi.org/10.5194/egusphere-egu26-21081, 2026.

The link between rock glacier velocity and climatic forcing is well established in permafrost research, especially for rock glaciers. This understanding underpins the inclusion of rock glacier velocity as an associated parameter of the Essential Climate Variable “Permafrost” within the Global Climate Observing System since October 2022. In this context, the rock glacier velocity (commonly abbreviated as RGV) is defined as a spatially averaged interannual horizontal velocity time series related to a RG unit or a part of it. However, RGV does not invariably track climatic forcing in a simple, linear manner, which can obscure the climatic signal. In this study, we combine primarily multi-decadal RGV monitoring with long-term observations of ground surface and near-surface temperatures, as well as spring water temperatures, at two sites in the Hohe Tauern, Austrian Alps: the Dösen rock glacier (DOE) and the Hinteres Langtalkar rock glacier (HLK). Both are well-developed, typical alpine rock glaciers. Each features a dominant rock glacier spring that drains runoff from the landform and its contributing hydrologal catchment. Annual in-situ geodetic surveys began in 1995 (DOE) and 1999 (HLK). Ground surface and near-surface temperatures, along with several meteorological variables, have been monitored using miniature temperature loggers and standard meteorological sensors since 2006 at both sites. Spring water temperature monitoring started in 2016 at DOE and 2017 at HLK. Our results indicate a clear relationship, in part, between RGV and temperature (air, ground, water). However, this relationship weakens or disappears where geodetic points are not, or are only partially, representative of permafrost creep. Moreover, summer spring-water temperatures can be damped by heat exchange with internal ice, such that melt of the ice component buffers water peak temperatures. These findings underscore the importance of parallel, co-located monitoring of ground, water, and air temperatures (and other climatic parameters), alongside carefully designed geodetic sampling that targets zones of active permafrost creep.

How to cite: Kellerer-Pirklbauer, A. and Kaufmann, V.: Velocities of rock glaciers and their surface, near surface and hydrothermal regimes in the Austrian Alps: Clear signs of climate change?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21296, https://doi.org/10.5194/egusphere-egu26-21296, 2026.

In recent years, in situ monitoring of rock glacier displacement has become more challenging. Unstable slopes, higher probability of gravitational movement due to destabilization processes and rock fall are negatively impacting the accessibility of research sites. To maintain long-term time series, current monitoring techniques need to be adapted.

One example of a research site affected by this is Äußeres Hochebenkar rock glacier (46°50'0"N, 11°0'30"E, Ötztal Alps, Austria). The rock glacier has been subject to velocity measurements since 1938, making it one of the longest time series worldwide. Differential Global Navigation Satellite System (dGNSS) measurements are carried out since 2007. Aside minor data gaps, velocity data have been available at annual resolution since 1997 from four cross sections and a longitudinal profile. Each profile consists of 6 to 12 individual block positions.

For the majority of the time series, the flow velocity was hardly more than 1 m/a on average. Since 2018, an exponential increase of rock glacier motion has been observed in the lowest section, showing the destabilization of this part of the rock glacier. During the last three years, maximum displacement values at individual blocks increased from 20 m/a to almost 50 m/a in 2024 and 75 m/a in 2025.

Accessing the block profiles in the destabilized section to carry out dGNESS measurements has become challenging. To ensure the continuity of the time-series, UAV surveys have been incorporated in the monitoring program. In 2024 and 2025, multitemporal optical imagery was acquired in addition to dGNSS data. High-resolution othormosaics and digital elevation models were derived from the UAV imagery using Structure-from-Motion (SfM) photogrammetry techniques. This enables the calculation of spatially distributed displacement vectors over the whole rock glacier from multitemporal hillshades using image correlation algorithms and provides alternative observations of block displacement.

We present the displacement rates for the years 2024 and 2025 using the most recent workflow, comparing displacement rates from dGNSS measurements with those derived from mapping on high-resolution orthomosaics and image correlation of multitemporal hillshades. We show how dGNSS displacement can be complemented by and compared to UAV-based methods. We try to address the opportunities and uncertainties lying within these approaches for mountain landforms that are reacting quickly to environmental changes, assuming that more and more comparable cases will arise under current and future climatic conditions in high mountain regions.

How to cite: Hartig, A., Stocker-Waldhuber, M., Seiser, B., Hartl, L., and Fischer, A.: Long-term monitoring of rock glacier displacement - adaptation of methodology in response to new challenges, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19657, https://doi.org/10.5194/egusphere-egu26-19657, 2026.

As a result of climate change, temperatures in the European Alps are rising twice as fast compared to the global average, leading to unprecedented glacier retreat. Deglaciating alpine landscapes are considered extremely dynamic, evolving rapidly over space and time. One of the legacies of glacial activity is buried ice, also known as legacy or dead ice, describing ice that survives in the proglacial area for years to decades after glaciers retreat due to isolation from solar radiation and thermal effects by a sediment cover. Buried ice plays an important role in alpine basins, for instance, by providing long-term water storage. It is also likely to be an important influence on geomorphic processes, such as erosion. Quantification of erosion and deposition patterns from DEMs of difference (DoDs) may be problematic if DoDs do not distinguish geomorphic change from buried ice melt out. Such distinction is commonly omitted in studies, as ground-based geophysical measurements (e.g. Electrical Resistance Tomography, ERT) may need to be applied, extremely difficult given the challenges associated with accessing steep alpine terrain and the spatially extensive areas that may need to be measured. The extent of buried ice is therefore likely to be poorly estimated.

Satellite-based thermal remote sensing may provide a solution to this problem. Indeed, as an example, Interferometric SAR may be used to detect to a very high vertical precision the surface changes that suggest buried ice. However, the spatial resolution of such data may be inefficient when the surface changes are complex. Recent developments in drones and thermal sensors include compact drones with high quality thermal sensors, such as the DJI Mavic 3T. Drones have the benefit of (1) providing a higher spatial resolution compared to satellite thermal remote sensing, and (2) covering larger areas, compared to existing methods of buried ice detection, such as ERT.

In this research, a thermal drone was tested to identify buried ice in the Turtmann basin, a rapidly deglaciating Alpine valley in the Canton of Valais (southwestern Switzerland). Areas known to contain buried ice were surveyed. The assessment of the thermal images showed high coherence between cold patches on the images with known presence of buried ice.

This study highlights the potential for thermal drones in assessing and monitoring geomorphological processes in deglaciating environments, with a specific focus on buried ice. The results provide guidelines on equipment, survey design and execution, as well as data analysis for the use of thermal drones in alpine environments. Future research could focus on identifying approaches for validating the method for surveying areas with no prior knowledge on buried ice. There is a huge potential for the use of thermal drones that is yet to be explored.

How to cite: Repnik, L., Comiti, F., Gianini, M., Argentin, A.-L., Pitscheider, F., and Lane, S.: UAV-based thermal mapping for interpreting geomorphological processes in complex alpine environments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16984, https://doi.org/10.5194/egusphere-egu26-16984, 2026.

Despite major advances in paleoclimatology, key uncertainties remain regarding Holocene climate variability in the Southern Hemisphere, particularly concerning the evolution of the position and intensity of the Southern Westerly Winds (SWW) and their influence on high mountain cryospheric systems. The Subtropical Andes of Chile (30–35°S), located near the northern margin of SWW influence, offer an exceptional geomorphic record derived from glacial and periglacial ice in response to past climatic changes, and therefore suitable for reconstructing Holocene SWW variability.

Well-preserved glacial landforms, such as moraines, have been widely used to reconstruct past periods of increased moisture (e.g. Aguilar et al., 2022; Fernández-Navarro et al., 2023, 2024; García et al., 2024; Sagredo et al., 2017; Zech et al., 2017). In parallel, recent inventories show that the Subtropical Andes of Chile and Argentina host the most extensive periglacial belt in the Southern Hemisphere (Barcaza et al., 2017; DGA, 2022; Masiokas et al., 2020). Rock glaciers, indicative of sustained cold-ground and relatively arid conditions (Azócar & Brenning, 2010), therefore represent a major but still underutilized paleoclimatic archive. Although recent studies have demonstrated the potential of cosmogenic exposure dating of rock glaciers for paleoclimate reconstruction (e.g. Amschwand et al., 2021), this approach has remained unexplored in the Subtropical Andes until now.

Although glacial and periglacial landforms commonly coexist within the same catchments in the Subtropical Andes of Chile (e.g., Aguilar et al., 2022; Carraha et al., 2024), their temporal and morphostratigraphic relationships remain poorly constrained. Consequently, the timing and climatic drivers of glacial and periglacial phases are still mostly unknown (García et al., 2024; Jones et al., 2019), limiting our understanding of the Holocene paleoclimate and its cause. Here we present new ¹⁰Be cosmogenic exposure ages from moraines and surface blocks on multi-lobate rock glaciers in the Piedra Valley (30°S) to help constrain the timing and extent of periglaciaton of this valley after the LGM and into the Holocene. This combined glacial–periglacial chronological framework allows us to explore the timing of climatically controlled cryospheric response during the Holocene and their potential relationship with regional hydroclimatic variability. Our results contribute to a better understanding of cryosphere–climate interactions in mid-latitude mountain environments and provide new insights to test proposed hypothesis regarding glacial-periglacial transition at the end of the last ice age, as well as Holocene climate change in the subtropical southern latitudes.

How to cite: Carraha, J., García, J. L., Fernández-Navarro, H., and Amschwand, D.: Holocene climate variability as reconstructed from 10Be dated glacial and periglacial phases in the Subtropical Andes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5879, https://doi.org/10.5194/egusphere-egu26-5879, 2026.

Sedimentary archives from inner-Alpine settings predating the Last Glacial Maximum (LGM) are rare due to the strong erosional impact of LGM glaciers on these landscapes. In the Eastern Alps, a key site for reconstructing pre-LGM inner-Alpine environmental conditions is located near Innsbruck (Austria): the so-called Höttinger Breccia. This >1300m -thick sedimentary succession consists of basal lodgement till overlain by a thick sequence of alluvial to talus-slope deposits with intercalated aeolian and lacustrine sediments, capped by LGM moraine. Over a century ago, this succession also provided some of the first evidence for the multiple, cyclical nature of the ice ages.

Despite the significance of this site for reconstructing pre-LGM inner-Alpine environmental conditions, chronological constraints on these sediments remain limited. Previous optically stimulated luminescence (OSL) dating of quartz provided only minimum age estimates for the Höttinger Breccia because the quartz signals approached saturation. To overcome this limitation, this study applies infrared-stimulated luminescence (IRSL) dating to feldspar, as the IRSL signal saturates at much higher doses than the quartz OSL signal, thereby enabling dating further back in time. We exploit a range of post-IR IRSL (pIRIR) feldspar signals at stimulation temperatures from 110°C to 290°C to systematically investigate feldspar-related issues of anomalous fading and partial bleaching. We (i) present an optimized dating protocol that identifies the IRSL signal providing the best trade-off between signal stability and bleachability; (ii) report preliminary age estimates obtained from samples taken at various stratigraphic depths within the Höttinger Breccia succession; and (iii) integrate these age estimates into a 3D model of the sedimentary succession.

This combined chronological and spatial framework provides a basis for reconstructing Mid Pleistocene paleoenvironmental conditions in an inner-Alpine valley that otherwise preserves almost no geomorphic record of pre-LGM paleoclimate variability.

How to cite: Drexler, M., Sanders, D., and Meyer, M. C.: Luminescence dating and 3D modelling of a Mid Pleistocene inner-alpine alluvial-talus succession, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10579, https://doi.org/10.5194/egusphere-egu26-10579, 2026.

Supraglacial landslides constitute an important component of glacier–landscape interactions, with the potential to influence glacier dynamics, mass balance, surface evolution, and sediment transport. From a geomorphological perspective, they contribute to the formation of large, anomalously positioned moraines and may, in some cases, facilitate the transition from glacier ice to rock glaciers. However, the glaciological and geomorphological significance of supraglacial landslides is highly variable and depends on landslide geometry, position relative to glacier accumulation and ablation zones, event timing, and the potential for long-term preservation of deposits.

This study investigates the spatial distribution and timing of large supraglacial landslides (>0.2 km² of deposits) across the Southern Andes. Landslide mapping was conducted using a multi-stage remote-sensing approach. First, potential supraglacial landslide locations were identified using high-resolution satellite imagery. Second, time series of medium-resolution satellite data (Landsat, ASTER, and Sentinel) were analysed to constrain the timing of individual events by estimating the occurrence window length (OWL), defined as the interval between the most recent image without a visible landslide and the oldest image in which the landslide deposit is observed. Third, morphometric characteristics were derived, and landslide locations were analysed in relation to glacier zones.

A total of 334 potential supraglacial landslides were identified, of which 198 deposits larger than 0.2 km² were detected on more than one satellite image between 1984 and 2025. For 59 of these landslides, sufficient time-series satellite imagery was available to constrain the OWL and thus approximate event timing. The results indicate that supraglacial landslides in the Southern Andes are substantially more frequent than previously recognised. The mapped inventory and timing constraints provide a basis for future analyses assessing the impact of individual landslides on glacier dynamics and their broader geomorphological significance.

This research was funded by the National Science Centre, Poland, project number 2021/42/E/ST10/00186

How to cite: Ewertowski, M. and Tomczyk, A.: Distribution of supraglacial landslides in the Southern Andes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15168, https://doi.org/10.5194/egusphere-egu26-15168, 2026.

Crevasse squeeze ridges (CSRs) are landforms indicative of glacier surging and ice stream shut down. They form during fast ice flow, when high basal water pressures and extensional ice flow cause hydrofracturing in the base of the glacier and subsequent squeezing/injection of sediment into basal crevasses. When the fast ice flow phase ends, ice stagnates and down wasting of the ice surface occurs. If lateral support is maintained the sediment ridges are preserved as the glacier passively retreats. Geometries of these ridge networks can thus provide insights into subglacial conditions during phases of fast ice flow. This is important because the rapid movement of ice from areas of accumulation to ablation zones, during fast ice flow phases, exposes a greater area of ice to melting having long term impacts on the mass balance of these glaciers.

CSR characteristics have been inconsistently reported in the literature and in some cases have been misidentified. Here we present the first global dataset combining CSR information mined from the literature with new mapping and use this to define CSR characteristics in both surging and ice stream contexts as well as in terrestrial and marine settings. Using ArcGIS Pro, we map ridges from high resolution aerial imagery and digital elevation models, and extract metrics on ridge lengths, network density, and orientations in relation to ice flow direction. CSRs have been mapped at modern surge-type glaciers in Iceland and Svalbard, and in palaeo-landscapes in central Canada, the British Isles, and Northern Europe related to ice stream shutdown. Furthermore, we categorise the data into marine and terrestrial environments because CSRs are often better preserved in marine settings, due to the action of subaerial and meltwater erosional processes occurring on land.

This new dataset provides a representative understanding of CSR morphologies to allow better identification of the landform in the future, which will help to understand subglacial processes beneath fast-flowing ice masses. Understanding basal conditions in any glacial system is challenging due to the difficulties of acquiring direct measurements at the base of the glacier. CSRs represent these basal conditions and can therefore provide insights.

How to cite: Ranger, A., Rea, B., Spagnolo, M., Kurjanski, B., Newton, A., Pearce, D., and Lovell, H.: Mapping crevasse-squeeze ridges- defining characteristics for improved understanding and identification of these landforms, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18716, https://doi.org/10.5194/egusphere-egu26-18716, 2026.

In the context of ongoing glacier retreat and slope destabilisation, rockfalls in high-alpine cirque headwalls are becoming increasingly relevant and constitute an integral component of paraglacial process chains. 

On the Höllentalferner (Wetterstein Mountains, Bavarian Alps), two prominent rockfall events occurred in recent years (2016 and 2024), depositing large amounts of debris onto the glacier surface and forming distinct supraglacial debris bodies. The aim of this study is a quantitative assessment of both events focusing on (i) quantifying the rockfall volumes using multi-temporal surface reconstructions and DoD-based estimates, (ii) assessing how supraglacial debris cover modifies glacier ablation by comparing bare-ice melt with melt beneath debris (i.e., differential ablation), and (iii) characterizing the spatio-temporal evolution of debris-body morphology (extent, thickness and internal redistribution) across consecutive observation epochs.

Methodologically, a multi-temporal DEM-of-Difference (DoD) approach is applied that combines, co-registers, and differences UAV/aerial-image-based SfM photogrammetry with airborne laser scanning (ALS) datasets. For this purpose, RTK-UAV surveys (2023 and 2025) are processed photogrammetrically into point clouds, DEMs and orthomosaics. The DEMs are aligned to stable terrain before DoDs are used to quantify elevation and volume changes.

First results indicate that volume estimates strongly depend on the chosen method: for the 2016 rockfall, estimates of approx. 10,410 m³ (extrapolation from bare-ice melt) and 15,510 m³ (Topo-to-Raster interpolation) are obtained, contrasted by a detachment volume of 5,206 m³. Interpolation-based DoD analyses yield epoch-specific volumes on the order of 19,443–31,519 m³, largely driven by differential ablation between debris-covered and adjacent bare-ice areas (and associated changes in the surrounding glacier surface). For the 2024 rockfall, current estimates amount to 20,171 m³ (extrapolation) and 10,128 m³ (detachment volume). Comparing bare-ice melt with melt beneath debris for the 2016 event indicates a pronounced insulating effect: between 2016 and 2018 (extrapolated), bare ice lowered by 4.3 m, whereas the debris-covered area lowered by only 0.8 m (differential ablation −3.5 m).

The findings highlight (i) the need for a multi-method framework to robustly constrain volumes and associated uncertainties, (ii) the key role of debris-driven melt/settlement processes for interpreting DoD signals on debris-covered glacier surfaces, and (iii) the potential of rockfalls deposits to locally delay glacier melt by supplying insulating debris.

How to cite: Kohlhage, T., Himmelstoss, T., Hagg, W., Stark, M., Heckmann, T., and Haas, F.: The evolution and insulation effect of two recent rockfalls on the Höllentalferner glacier in the Bavarian Alps: A multi-temporal analysis of volume and morphology using LiDAR and UAV data., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17096, https://doi.org/10.5194/egusphere-egu26-17096, 2026.