PICO
This session welcomes all contributions from mountain permafrost research in all periglacial environments: from high Arctic climates through any continental regions (e.g. Alpine, Andean, Tibetan) to arid unglaciated areas of Antarctica. We welcome a broad spectrum of ice-rich and ice-poor landforms, including rock glaciers, talus slopes, plateaus, ice-cored moraines, steep rock slopes, and thermokarst. We particularly encourage contributions that enhance understanding thermo-hydro-mechanical-chemical processes at slope and regional scales. The combination of multiple methods and newly developed approaches is of particular interest, as well as long-term studies or characterization of new permafrost sites with state-of-the-art methods. Geophysical measurements and analysis (e.g., ERT, SRT, DAS, EM, IP, GPR, TLS), in-situ measurements (e.g., temperatures, discharge, kinematics, GNSS), remote sensing surveys (e.g., optical, thermal, InSAR, UAV), modeling from past to future processes and scenarios, early warning systems, and data analysis improvements thanks to machine learning and artificial intelligence tools can be submitted.
We aim to improve the understanding of the response of mountain permafrost to climate change. This session aims to create a new opportunity for meeting and exchange within the mountain permafrost community and its fellows to promote joint research developments and improve understanding of processes.
ECS are encouraged to submit their work to this session. The presentation will be preferentially in presence (PICO).
Permafrost Beer and Burger 🍔🍻
On Tuesday evening (5 May), we will meet for burgers and beers at Weinschenke (Franzensgasse 11, 1050 Vienna) from 19:30 onwards. Thanks to PermaCOST, a limited number of beers is on the house – so come on time! Food and other drinks will be at your own expense.
Spots are limited, so please sign up in advance here:
https://doodle.com/group-poll/participate/dBXGjxJa
Feel free to share this invite with others!
PICO: Tue, 5 May, 16:15–18:00 | PICO spot 1a
In late May 2025, a series of large rock failures from Kleines Nesthorn in the Swiss Lötschental (Lötschen valley) fell directly onto the Birchgletscher (Birch Glacier), loading the latter with around 4 million m3 of rock. On May 28, following several days of acceleration, Birchgletscher collapsed in its entirety, claiming one life and causing the near-total destruction of the historic village of Blatten (which had been fully evacuated prior to the event). Totaling more than 9 million m3 of rock and glacier ice (with a ratio of about 3:1), the rock-ice avalanche dammed the river Lonza and led to the formation of a lake that damaged additional parts of the village.
The rock failures that initiated the hazard cascade originated from the north-east face of Kleines Nesthorn, a formerly 3336 meter tall peak. Like all areas at this elevation, this face is expected to have experienced important ground temperature changes in the past decades. In this contribution, we ask how these changes may have affected the observed hazard cascade. We analyzed climatic changes (air temperature and precipitation) and snow cover, simulated permafrost changes, and assessed the geologic preconditioning and failure kinematics. We then attempt to propagate these changes through the hazard cascade to understand their possible impact on the rock slope failures. To do so, we employed a combination of data from weather stations, satellite data, climate models and numerical modeling. Our findings demonstrate the complexity of the Nesthorn-Birchgletscher hazard cascade and highlight challenges and research gaps for assessing the role of permafrost on large rock slope failures in a changing climate.
How to cite: Jacquemart, M., Brondex, J., Knuth, F., Weber, S., Kenner, R., Aaron, J., Gischig, V., de Silva, R., Spielmann, R., Schneider, M., Schumacher, D. I., Welty, E., Reist, F., Senn, I., and Farinotti, D.: Impact of permafrost changes on the 2025 Nesthorn-Birchgletscher hazard cascade, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20730, https://doi.org/10.5194/egusphere-egu26-20730, 2026.
Some of the largest rock slope failures in the European Alps today occurred with a significant lag time of several thousand years after glaciers retreated from the Last Glacial Maximum. Amongst other processes, the inert permafrost evolution can partly explain the delayed failure timing. Here, we challenge this hypothesis using the Köfels rock slide (Austria, 3.1 km³ failure volume, 9527–9498 cal BP) by retracing thermal conditions and reassessing the failure mechanics of one of the most prominent crystalline rock slides in the Alps. Our coupled simulations of ice-permafrost temperatures suggest that permafrost was maintained at the upper slope parts, mainly above glacier surface elevations, throughout the past 40 ka. Yet in the period before the rock slope failure, permafrost was preserved only at the highest elevation. It was lost within the hanging valley behind the failed mountain flank. This likely led to hydrogeological recoupling, enhancing groundwater flow towards stability-relevant zones. In addition, we deploy new rock mechanical tests to assess the rock bridge shear strength of the local orthogneiss and run mechanical simulations in order to decipher and better discuss the complex promoting factors of the Köfels rock slide (currently in process). Large permafrost rock slope failures are not only attributed to the loss of cohesive rock and ice material strength by warming temperatures, rather than to the interwoven hydro-thermo-mechanical system adaptation resulting from permafrost degradation.
How to cite: Pfluger, F., Bever, L., Weber, S., Fürst, J., and Krautblatter, M.: The role of permafrost in large rock slope failures in the early Holocene - An analysis of the Köfels rock slide (3.1 billion m³), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11138, https://doi.org/10.5194/egusphere-egu26-11138, 2026.
Permafrost degradation in alpine regions driven by climate warming is increasing the likelihood of rock slope destabilization. However, the mechanical response of fractured rock-ice systems to repeated freeze-thaw cycles and long-term warming remains poorly monitored and understood. Using a decade of continuous passive seismic data recorded at different stations, this study investigates how seasonal and long-term environmental forcings affect the mechanical properties of a steep bedrock permafrost site at the Matterhorn Hörnligrat ridge (Valais, Switzerland). We applied spectral analysis (single-station and site-reference spectral ratios), auto- and cross-correlation of ambient seismic noise combined with microseismic event detection and analysis to track the long-term temporal variations and evolution in resonance frequencies and seismic wave velocity within the rock mass, and in the spectral characteristics of microfracturing events. We observed strong, reversible seasonal variations of mechanical parameters linked to freeze-thaw cycles, characterized by reduced stiffness in summer and increased stiffness in winter. Long-term observations showed a continuous decrease in resonance frequencies, wave velocities, and peak frequencies of the microseismic events, indicating progressive and irreversible mechanical weakening of the rock-ice system.
These results demonstrate that passive seismic monitoring enables the detection of both reversible and irreversible mechanical changes in alpine permafrost slopes, providing early indicators of progressive destabilization under ongoing climate warming.
How to cite: Strallo, V., Colombero, C., Beutel, J., and Weber, S.: Long-term Passive Seismic Monitoring of Permafrost Dynamics at the Matterhorn Hörnligrat (Valais, Switzerland), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13607, https://doi.org/10.5194/egusphere-egu26-13607, 2026.
Due to climate change, ice masses are thawing rapidly. This leads to drastic changes in water discharge, increased erosion, decreased biodiversity, as well as an increasing risk of droughts. However, the amount of subsurface ice is often unknown. To better understand the implications of decreasing ice masses, the first step is to determine the initial ice distribution of the region of interest. One of the few places in the German Alps where we still find glaciers and permafrost is the Zugspitze. It is the highest mountain in Germany and has a long observational history dating back to 1820, which is present-day coordinated by the Virtual Alpine Observatory.
Here, we present the framework of creating a complement first dataset by conducting electrical resistivity tomography measurements and seismic refraction tomography. For this, we will measure ca. ten profiles across the 2 km diameter of the horseshoe-shaped Zugspitzplatt to decipher permafrost ice contents within the blocky surface, ice depth distribution and its state of degradation. To verify those findings, the model is tested against both data from a superconductive gravimeter and the isotopic concentration of the outflow to distinguish glacier water from permafrost water. This contribution shows the conceptual framework with which we will analyze the future water potential coming from the permafrost at the Zugspitzplatt in the framework of the AlpSenseAdapt project.
How to cite: Gahr, S. and Krautblatter, M.: Using electrical resistivity tomography and seismic refraction tomography to decipher permafrost ice distribution and loss at the Zugspitze (Germany) complementary to superconductive gravimeter and isotope chemistry measurements, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18413, https://doi.org/10.5194/egusphere-egu26-18413, 2026.
This paper discusses mechanical modelling strategies for instable permafrost bedrock. Modelling instable permafrost bedrock is a key requirement to anticipate magnitudes and frequency of rock slope failures in a changing climate but also to forecast the stability of high-alpine infrastructure throughout its lifetime.
The last 5-10 years have brought upon significant advances in the (i) knowledge of relevant hydrostatic pressures in permafrost rock, (ii) the brittle-ductile transitions of ice relevant for larger permafrost rock slope failures and (iii) techniques that can help to decipher the preparation phase of large rockslides also (iv) many new examples have delivered additional insight into multi-phase failure.
Degrading permafrost will act to alter (i) rock mechanical properties such as compressive and tensile strength, fracture toughness and most likely rock friction, (ii) warming subcero conditions will weaken ice and rock-ice interfaces and (iii) increased cryo- and (iv) hydrostatic pressures are expected. This paper presents data and strategies how to obtain relevant (i) rock mechanical parameters (compressive and tensile strength and fracture toughness, lab), (ii) ice- and rock-ice interface mechanical parameters (lab), (iii) cryostatic forces in low-porosity alpine bedrock (lab and field) and (iv) hydrostatic forces in perched water-filled fractures above permafrost (field).
This contribution will focus on three recent events, the Bliggspitze 2007, the Fluchthorn 2023 and Kleines Nesthorn/Blatten 2025 rock slope failures which have provided significant new insights in the mechanics of premafrost rock slope detachment, due to novel observational data, lab results and resulting mechanical models.
How to cite: Krautblatter, M., Pfluger, F., Mühlbauer, S., and Offer, M.: Understanding the mechanical destabilization of large permafrost rock slope failures using data, samples and models from the Bliggspitze 2007, Fluchthorn 2023 and Kleines Nesthorn/Blatten 2025 failures, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20970, https://doi.org/10.5194/egusphere-egu26-20970, 2026.
Quantifying ice and water in the subsurface is key to advancing our understanding of permafrost-related processes and to supporting hydrogeological management in cold regions. Electrical resistivity methods are well established as non-invasive tools for discriminating between frozen and unfrozen ground due to the high resistivity of frozen materials. However, solid rocks are also highly resistive, which makes a quantitative estimation of ice content based on resistivity alone challenging. The spectral induced polarization (SIP) method, which allows to measure the conductivity and polarization of rocks and soils, has been proposed as a complementary method for the investigation of frozen ground as ice exhibits a characteristic polarization response in the kHz frequency range due to protonic defects in its crystal lattice. In practice, however, collecting SIP data in such a frequency range is challenging, particularly in alpine environments, due to the logistical constraints and strong capacitive coupling effects related to the high contact resistance between electrodes and the ground. Recently, polarization effects at lower frequencies (< 100 Hz) associated with ice–water interfaces have been reported at the field scale and in laboratory experiments. To quantitatively assess these effects, we present results from experiments conducted at two different scales. First, we show laboratory experiments investigating the SIP response of blank ice features in solid rocks with varying ice volumes and temperatures ranging from +5 °C to −10 °C. Second, we present field SIP data collected during summer 2025 using borehole electrodes in the active rock glacier Muragl (Grisons, Swiss Alps). In the laboratory experiments, holes were drilled into rock samples and SIP measurements were performed after filling the holes with air, water, or ice, allowing a direct comparison of the polarization response for the different pore fillings. We identify a strong polarization effect below 100 Hz for ice-filled holes, while the response remains low when the holes are filled with water or air. Increasing the hole size—and thus the ice volume and the ice–water–rock interfacial area—results in an increase in the polarization strength and a shift of the maximum polarization toward lower frequencies. The SIP field data were acquired using borehole tomography, as borehole electrodes are positioned closer to the ground ice than surface electrodes, enabling a more direct comparison between field and laboratory observations. The results reveal an anomaly characterized by low electrical conductivity and increased polarization starting at approximately 1 Hz in a depth where drillings in summer 2024 revealed relatively high ice content. Overall, our results confirm the presence of a low-frequency polarization effect at ice–water interfaces and demonstrate its potential to image ground ice in alpine permafrost and seasonally frozen soils.
How to cite: Moser, C., Bast, A., Francis, S. M., Halisch, M., Hauck, C., and Flores Orozco, A.: Understanding the low-frequency electrical properties of ice–water interfaces from laboratory and field experiments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14080, https://doi.org/10.5194/egusphere-egu26-14080, 2026.
Electrical Resistivity Tomography (ERT) is a widely used geophysical method for investigating permafrost in challenging mountain environments, such as rock glaciers (Hauck and Kneisel, 2008). This study focuses on optimizing ERT acquisition strategies using modern high-quality multi-channel georesistivity meters, steel-net electrodes, and appropriate acquisition schemes, in order to efficiently and rapidly acquire multiple ERT transects and reliably characterize the internal structure of rock glaciers, despite complex surface conditions.
As recently proposed by Pavoni et al. (2025), the use of light steel-net electrodes facilitates the deployment and removal of ERT transects in blocky terrain, ensuring optimal galvanic contact without compromising data quality. In addition to these practical benefits, the choice of acquisition scheme strongly influences survey efficiency and data reliability. Hybrid acquisition schemes based on Dipole-dipole and Multigradient multi-skip approaches, when combined with multi-channel instruments, allow for rapid data acquisition, improved model sensitivity, and enhanced evaluation of dataset quality.
In this work, we compare the performance of a mixed Dipole-dipole and Multigradient multi-skip scheme with the traditional Wenner-alpha configuration. While traditional Wenner-alpha measurements are usually acquired only in the direct configuration, the Dipole-dipole and Multigradient schemes enables the acquisition of a substantially larger number of quadripoles within the same time frame, including both direct and reciprocal measurements, which provide a more robust estimation of data error by accounting for both instrumental and systematic contributions (Binley et al., 1995).
Furthermore, we evaluate the Polo-Dipole configuration’s potential to increase model sensitivity at depth (White et al., 2003), facilitating a more reliable identification of the bottom of the frozen layer within rock glaciers. Measurements were collected in both direct and reciprocal geometries, with the remote electrode deployed at two different positions and two different distances on opposite sides of the transect. Testing these alternative positions and distances of the remote electrode provided an additional way to assess data quality, confirming the robustness of the Polo-Dipole setup and its ability to increase investigation depth without significantly affecting acquisition time.
Overall, the integration of high-quality multi-channel instruments, light steel-net electrodes, and optimized acquisition strategies enhances model sensitivity and data-quality assessment while improving operational efficiency. This approach enables the rapid acquisition of multiple transects within a single field campaign and supports the development of quasi-3D resistivity models of rock glacier structures.
References
Binley, A., Ramirez, A., & Daily, W. (1995, April). Regularised image reconstruction of noisy electrical resistance tomography data. In Proceedings of the 4th Workshop of the European Concerted Action on Process Tomography, Bergen, Norway (pp. 6-8).
Hauck, C., and Kneisel, C.: Applied Geophysics in Periglacial Environments, Cambridge University Press., 2008.
Pavoni, M., Peruzzo, L., Boaga, J., Carrera, A., Barone, I., & Bast, A. (2025). Brief communication: Use of lightweight and low-cost steel net electrodes for electrical resistivity tomography (ERT) surveys performed on coarse-blocky surface environments. The Cryosphere, 19(10), 4141-4148.
White, R. M. S., Collins, S., & Loke, M. H. (2003). Resistivity and IP arrays, optimised for data collection and inversion. ASEG Extended Abstracts, 2003(2), 1-4.
How to cite: Pavoni, M., Guglielmin, M., Boaga, J., Cassiani, G., Carrera, A., Peracchi, S., Zumiani, M., Forte, E., Ponti, S., and Peruzzo, L.: Optimizing Electrical Resistivity Tomography Acquisition Strategies in Rock Glacier Environments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1728, https://doi.org/10.5194/egusphere-egu26-1728, 2026.
As climate change leads to the retreat of mountain glaciers worldwide, rock glaciers are increasingly recognised as important hydrological buffers in high-altitude catchments. Unlike clean-ice glaciers, these debris-covered formations are geophysically complex, making regional estimates of their water storage consistently challenging. Current assessments usually rely on simple area–volume scaling methods based on the surface slope, which overlook the flow behaviour of individual landforms.
In this contribution, we introduce GRIT (Geospatial Rock-glacier Ice Thickness Model), an open-source computational framework that infers ice thickness from satellite-derived surface kinematics, applying a Glen-type viscous flow law. It determines thickness by integrating local slope data from a high-resolution digital elevation model (DEM) with surface horizontal velocity measurements obtained through feature tracking in high-resolution optical satellite imagery.
To constrain the rheology, we calibrate the effective creep parameter (B) using 80 MHz ground-penetrating radar (GPR) profiles collected at the Vej del Buoc rock glacier in the Maritime Alps. Our results reveal a range of B values indicative of a significantly softer effective rheology than that of clean temperate ice, consistent with the presence of interstitial unfrozen water and debris inclusions that reduce the mixture's viscosity. GRIT is designed for scalability and can be applied to regional inventories to derive spatially explicit thickness and water-equivalent maps.
To our knowledge, this is the first satellite-based, geospatial rheological inversion toolbox specifically designed for determining rock-glacier ice thickness and water-equivalent storage. By combining satellite-observed movement with site-specific geophysical calibration, GRIT offers a scalable, physically grounded method for monitoring the debris-covered cryosphere in mountain basins with limited data and for incorporating rock-glacier ice storage into regional water resource evaluations.
How to cite: Khajuria, V., Singh, S., Paro, L., Spagnolo, M., and Ribolini, A.: GRIT: Geospatial Rock-glacier Ice Thickness Model through Satellite-Derived Rheological Inversion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5157, https://doi.org/10.5194/egusphere-egu26-5157, 2026.
Multi-temporal InSAR techniques allow the detection of millimetric surface displacements, making them particularly suitable for monitoring slow-moving landforms, such as rock glaciers, at a regional scale. Optical data, and in particular Short-Wave Infrared (SWIR) bands, provide complementary information by enhancing the spectral response of bare debris and poorly vegetated surfaces.
This work aims to propose a workflow to recognize the presence of rock glaciers over large areas (approximately 10-100 km2) and to distinguish them from other geomorphological units through the integration of optical and interferometric data.
The approach was tested in a restricted study area (3.7 km2) in Alpe Visogno, in the municipality of Mello (SO), within a small lateral valley on the Rhaetian side of Valtellina (Northern Italy). This area hosts an atypical rock glacier due to its exposure (south) and relatively low mean altitude (2100 m a.s.l.). Such conditions make the area particularly suitable for investigating peculiar permafrost dynamics in an alpine environment.
Interferometric analysis was conducted using ascending-orbit Sentinel-1 data, covering the period from 10 May 2024 to 24 December 2024, corresponding to the snow-free season. Open-source processing tools were used to derive surface velocity maps for the area of interest. The correction of the Atmospheric Phase Screen (APS) was carried out using the Generic Atmospheric Correction Online Service (GACOS). This choice was based on a comparison of the residuals resulting from different correction approaches. The optical data came from a single Sentinel-2 image acquired during the summer period (08 August 2024) under snow-free conditions for the entire study area, reaching up to 2670 m a.s.l. This image was selected to maximize the radiometric quality and to minimize the effects of clouds and shadows. Subsequently, a specific spectral index (Debris Index) primarily derived from SWIR bands was defined. These bands are sensitive to the presence of moisture, such as that occurring in pores and fractures, and can be used to discriminate superficial layers with different textural properties. A threshold based on the 75th percentile was applied to the Debris Index to generate polygons representing the deposits. The integration of optical and interferometric data was supported by a statistical analysis, including both boxplots and clustering techniques (k-means and hierarchical Ward’s method).
The clustering identified two groups: a fast-moving cluster (average velocity of -24.4 mm yr-1) corresponding to rock glaciers, and a slow-moving cluster corresponding to simple debris deposits (average velocity of -11.1 mm yr-1). These results are strongly corroborated by field observations, confirming the effectiveness of the workflow in discriminating rock glaciers from other debris accumulations such as talus and colluvial deposits. Future developments will focus on testing the proposed workflow over larger and more heterogeneous areas to assess its robustness and transferability at local, regional, or supra-regional scales.
This study was carried out within the framework of the Italy-Switzerland Interreg VI-A project AMALPI MORE.
How to cite: Pisanu, D., Camera, C. A. S., and Azzoni, R. S.: Testing the integration of InSAR and optical data for rock glacier detection in a lateral valley of Valtellina (Northern Italy) , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5624, https://doi.org/10.5194/egusphere-egu26-5624, 2026.
Erosion at rock glacier fronts can supply sediment to adjacent torrents, which can be mobilized as damaging debris flows. Understanding the mechanisms which govern this erosion process is therefore critical for hazard management in affected areas. Previous research shows that rock glacier advance and liquid water input are the two main drivers of erosion at rock glacier fronts. However, earlier studies that calculated erosion volumes at rock glacier fronts were limited to temporal resolutions ranging from months to years. Therefore, these studies exhibit a high uncertainty due to the opposing influences of rock glacier front advance and retrogressive erosion. This prevented an in-depth understanding of the underlying drivers of these processes and their magnitudes on a short timescale. To overcome this limitation, we adapt the setup by Aaron et al. (2023) and use a permanently installed LiDAR sensor to monitor surface changes at a rock glacier front. By calculating Digital Elevation Models of Difference (DoDs) with respect to the local surface normal, we are able to compute erosion volumes at an hourly temporal resolution. This enables the quantification of short-term and small-scale geomorphic changes at the rock glacier front, which could not be detected by previous studies.
Our study site is the fast-moving Ritigraben rock glacier (front velocity > 1cm/day) in the Mattertal (Valais). Its front is directly connected to a torrential channel, which regularly produced debris flows in the past and has been monitored for more than 30 years. Preliminary results show a link between erosion events and short-term precipitation with camera images showing signs of surface runoff in the affected areas. However, erosive events are triggered by comparatively common rainfall events. Small-scale reworking of material at the rock glacier front also occurs completely independently of precipitation events in some cases. Further investigation is needed to determine if the release of material is due to failure disposition from prior events and the rock glacier creep, or the influence of meltwater from the rock glacier body.
References
Aaron, Jordan, Raffaele Spielmann, Brian W. McArdell, and Christoph Graf (2023). “High-Frequency 3D LiDAR Measurements of a Debris Flow: A Novel Method to Investigate the Dynamics of Full-Scale Events in the Field”. In: Geophysical Research Letters 50.5. doi: 10.1029/2022GL102373.
How to cite: Ebert, S., Hirschberg, J., Spielmann, R., and Aaron, J.: Using near-continuous LiDAR monitoring to quantify erosionprocesses at a rock glacier front, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7401, https://doi.org/10.5194/egusphere-egu26-7401, 2026.
Permafrost degradation along the Qinghai–Tibet Engineering Corridor (QTEC) poses severe risks to infrastructure stability. While current monitoring techniques often lack sufficient spatial continuity or depth resolution, Distributed Acoustic Sensing (DAS) offers a scalable alternative for subsurface characterization. This study introduces a high-resolution imaging framework that leverages existing fiber-optic infrastructure and a Convolutional Neural Network (CNN) to isolate transient traffic-induced vibrations from low Signal-to-Noise Ratio (SNR) DAS records. By selectively stacking these detected signals, we expand the recoverable frequency range of ambient noise interferometry to 45 Hz (vs. 35 Hz for standard stacking), enabling the reconstruction of a 2D shear-wave velocity (Vs) profile near the Kunlun Mountain Pass. The imaging results clearly delineate the permafrost table and base, revealing a permafrost thickness of up to 90 m. Furthermore, we identify pronounced lateral heterogeneities and a structural discontinuity interpreted as a fault-controlled talik. This subsurface anomaly spatially coincides with localized subsidence observed via InSAR, highlighting a coupled structural–hydrothermal mechanism for degradation. Our workflow demonstrates the efficacy of AI-enhanced "dark fiber" sensing for identifying concealed cryospheric hazards in remote alpine regions.
How to cite: Cen, W., Cheng, F., Xia, J., Guan, J., Sun, H., Zhao, K., Wu, R., Chen, J., and Wu, T.: Fiber-Optic Seismology Reveals Structural–Hydrothermal Coupling in Permafrost Degradation on the Qinghai–Tibet Plateau, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8973, https://doi.org/10.5194/egusphere-egu26-8973, 2026.
Permafrost mapping in high-mountain environments is essential for understanding cryospheric processes and assessing cryopheric hazards due to climate change. Remote sensing-based permafrost mapping commonly relies on multiple climatological and topographical parameters, including land surface temperature, snow index, soil moisture, elevation, slope and aspect. However, accurately predicting subsurface permafrost conditions remains challenging. For mountain permafrost studies, rock glaciers are widely used as proxies for permafrost presence, and machine-learning models are often trained primarily on their spatial distribution. This approach introduces a systematic bias, as rock glaciers are typically concentrated above ~4200 m a.s.l., whereas permafrost occurrence is also controlled by local thermal regimes, soil properties, and moisture conditions, allowing its presence within valley settings. In this study, we investigate mountain permafrost occurrence and active layer characteristics in contrasting high-altitude environments using an integrated remote sensing and geophysical approach. Ground Penetrating Radar (GPR) surveys were carried out at two different geographical locations, Matiyan, Jammu and Kashmir, and Baralachala, Himachal Pradesh. The locations were chosen for their diverse lithology, elevation and climatic conditions. GPR data was collected in both common-offset and multi-offset modes using 80 MHz and 450 MHz antennas, aiming to enhance depth and resolution. The GPR data reveal clear subsurface signatures of frozen ground, including ice-rich layers and distinct active layer thicknesses, even in areas lacking visible rock glacier morphology. The ALT measurements ranged from 0.6 m to 1.2 meters depth in Matiyan, while Baralachala showing a shallower active layer of 0.2 m to 0.5 meters and reflecting colder climatic conditions and less surface disturbance. The findings of this study highlight the limitations of proxy-based permafrost mapping and provide a deeper understanding of mountain permafrost in changing climatic scenarios. Thus, the integration of remote sensing data with subsurface observations provides improved understanding of thermo-hydrological controls on mountain permafrost distribution.
How to cite: Mahanta, K. K. and Shukla, D. P.: Integrating Geophysical and Remote Sensing Techniques for Mountain Permafrost mapping in the Northwestern Himalaya, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10206, https://doi.org/10.5194/egusphere-egu26-10206, 2026.
Permafrost and seasonally frozen ground are critical components of the Arctic cryosphere, playing a fundamental role in regulating hydrological processes. Permafrost underlies approximately 13-18% of the Northern Hemisphere’s exposed land surface and stores vast quantities of organic carbon. Its thermal stability has profound implications for infrastructure, carbon cycle, and hydrological processes under changing climate. Modeling permafrost dynamics is critical, yet standard cryo-hydrological models often struggle to capture the complex phase changes in fine-grained soils, particularly in clayey soils where liquid water persists at temperatures well below the classical freezing point.
To overcome this challenge, we propose an advanced thermodynamic framework that moves beyond the classical soil freezing characteristic curves (SFCC). By incorporating adsorption potential (μads), this framework accounts for the exponential energy decay near mineral surfaces, physically explaining the persistence of liquid water in clay nanopores down to −80℃. While the theoretical foundation for this approach is established in the enthalpy-based solver WHETGEO-1D (Tubini & Rigon, 2022), we evaluate its significance through a comparative study using field forcing and hypothetical experiments.
We conducted this analysis in two stages. First, the 1D GEOtop model was applied to two sites along the Inuvik-Tuktoyaktuk Highway (Canada) using ERA5 and JRA-3QG reanalysis data (1950–2023). At this stage, the model performance was evaluated against ground temperature observations (2017–2022) to ensure realistic surface fluxes and ground temperatures. Second, using these validated forcing conditions, we performed hypothetical experiments to compare the classical and adsorption-aware frameworks across different soil types.
Our initial analysis indicates that the classical and adsorption-aware frameworks yield divergent results in the timing of latent heat exchange and moisture redistribution. By bridging the gap between pore-scale thermodynamics and Darcy-scale modeling, this study provides a robust roadmap for implementing next-generation physics into permafrost models.
How to cite: Tavonatti, M., Wani, J. M., Gruber, S., and Rigon, R.: Advancement in Permafrost Modeling: The Role of Adsorption-Aware Thermodynamics in Fine-Grained Soils, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14051, https://doi.org/10.5194/egusphere-egu26-14051, 2026.
Long-term fire histories are well documented across most North American temperate forest systems, yet the fire regimes of high-alpine treeline environments remain poorly understood. Here, we present a millennial-scale fire history from the Sawtooth Fen Palsa (SFP), a rare permafrost fen palsa located in the high-alpine treeline ecotone of the Beartooth Plateau, Wyoming, a permafrost system now unraveling due to recent decades of rapid warming. Analysis of paleoenvironmental proxies from peat sediments overlying permafrost reveals that a multi-century peak in fire activity occurred around 10,000 cal yr BP, coinciding with the afforestation of newly deglaciated, ice-free sites. This initial surge in fire activity was followed by a decline when orbitally driven increased growing-season temperatures likely promoted forest expansion at high elevations where moisture was not limiting. High severity fire activity increased again during the mid- Holocene (approximately 6,700–5,000 cal yr BP), when effective moisture increased, favoring subalpine forest expansion and increased connectivity of woody biomass (sagebrush and forest), enhancing the potential for canopy fire spread. Generally cooler and wetter conditions and possible year-round coverage of the fen palsa with snow and ice drove a near-absence of woody biomass burning at 5,000 cal yr BP. Rapid warming in recent decades has triggered the formation of dozens of thermal collapse ponds across the fen palsa. The frequency of these features has more than doubled since 2000 AD, underscoring the degradation of underlying permafrost in response to changing climatic conditions. Continued warming is expected to cause the complete loss of the permafrost lens, with far-reaching implications for ecosystem dynamics, disturbance regimes, and carbon and nutrient cycling.
How to cite: Tipkemper-Wolfe, A., McWethy, D., and Alt, M.: Millennial-Scale Fire and Vegetation Change from a Rare Mid-Latitude Permafrost Fen (Beartooth Plateau, WY, USA), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8432, https://doi.org/10.5194/egusphere-egu26-8432, 2026.
PermaCOST is a new international research network funded by the COST Action Association of the European Union (CA24157). This four-years project (2025-2029) brings together European permafrost researchers, stakeholders, and practitioners with expertise in different measurement techniques and permafrost conditions to work towards a coordinated and standardised monitoring of permafrost response to climate change.
Permafrost has been dramatically warming and degrading in most mountain and polar regions, with far-reaching and long-term implications for natural and anthropogenic environments. In this context of rapid changes and large socio-economic impacts, the increased scrutiny from the society and the growing demand for sound data from stakeholders make permafrost monitoring a timely and highly relevant field of research.
Documenting, analysing, and assessing the response of permafrost to climate change requires fundamental cross-disciplinary and cross-geographic knowledge that can only be achieved through coordinated and standardized monitoring activities. For years, European research groups have been at the forefront of operational and innovative permafrost monitoring activities, but they have not been able to further coordinate their activities or to establish widely accepted standards for data acquisition and processing.
Through an unprecedented network of experts and early career investigators, PermaCOST aims to promote and foster operational networking of permafrost researchers, stakeholders and practitioners to facilitate an overall comparability of data sets and time series of various permafrost variables for a better characterisation of the long-term permafrost evolution on the global scale.
PermaCOST is organised in five Working Groups (WGs) with the specific objectives to identify key novel permafrost monitoring methods (WG1), to homogenise permafrost data acquisition standards (WG2) and permafrost data processing standards (WG3), to assess the state and evolution of permafrost in Europe (WG4) and to promote the development of operational permafrost monitoring networks at national, regional, and European scales (WG5).
In this contribution, we will present the objectives and structure of the project, as well as the concrete tasks and ongoing activities in the WGs covering mountain, polar and marginal permafrost. We will also inform the permafrost community on how to join the network, and take advantage of the upcoming opportunities for networking, training, and research collaboration, through short-term scientific missions, travel grants, training schools and workshops.
How to cite: Mollaret, C., Hrbacek, F., Rouyet, L., Sjöberg, Y., Sirbu, F., Farzamian, M., Blöthe, J., Brardinoni, F., Pellet, C., Kellerer-Pirklbauer, A., Zebre, M., and Milceva, A.: PermaCOST: New International Research Network for Coordinated and Standardised Monitoring of Permafrost Response to Climate Change, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20454, https://doi.org/10.5194/egusphere-egu26-20454, 2026.
