Conference Agenda

Permafrost in high mountain environments is highly sensitive to climatic variations, impacting both landscape stability and hydrological systems. Electrical resistivity tomography (ERT) measurements could provide detailed information on subsurface conditions, revealing changes in resistivity that correlate with variations in lithology, ice content, temperature, or/and moisture. In this study, ERT monitoring has been conducted over a four-years period (2020-2023) to explore the distribution and evolution of permafrost at The Aiguille du Midi (located on the NW side of the Mont-Blanc massif) in the French Alps. A total of 3 cables of 32 take-outs each, 5 m spacing (thus 155 m long) were installed. They were deployed downwards from the summit in three directions (north, south and east face). However, with the extreme climatic conditions at this altitude, ERT measurements run into many problems (high contact resistance, cables cut-off because of lightning). Time-laps inversion of ERT measurements collected at different elapsed times was carried out. The resistivity distribution shows parts of the internal structure (galleries, elevator), fractures as well as the seasonal and annual variations of the active layer. A petrophysical analysis in laboratory on a rock sample taken from the site was carried out to evaluate the thermal dependence of electrical resistivity in a saturated condition. A petrophysical model descripting the thermal dependency of resistivity was used to connect ERT measurements to temperature in field conditions. Temperature distribution estimated from ERT was compared to the temperature measured in borehole on-site. Good correlation could be notieced between temperature estimated from ERT and that measured on-site in summer when data quality is good enough. However, poor data quality leads to errors in the temperature estimation in winter. This research demonstrates the effectiveness of ERT as a tool for long-term monitoring, evaluation of permafrost thermal conditions and hydrological dynamics in alpine environments.

Electrical resistivity tomography (ERT) is widely used to map, characterise and monitor alpine and periglacial environments with coarse, blocky surfaces. Typically, ERT measurements use steel electrodes combined with water-soaked sponges, but achieving good contact resistance between the steel electrodes and the ground to obtain high quality data can be logistically challenging and time consuming. To address this, we tested fist-sized, sand-filled conductive textile electrodes as an alternative to conventional steel electrodes.

We carried out ERT measurements on a landslide and two rock glaciers in the European Alps, comparing the performance of textile and steel electrodes. The precision and accuracy of the textile electrodes were tested using statistical methods, including the Wilcoxon-Mann-Whitney test, robust regression analysis and descriptive statistics.

The results showed that textile electrodes performed comparably to steel electrodes, providing good galvanic contact and accurate resistivity measurements. Measurements with textile electrodes showed lower contact resistance, which could benefit ERT monitoring. They also improved field logistics by being lighter, easier to transport and reducing the risk of injury during deployment. These advantages allow for faster ERT measurements and mapping of entire landforms.

However, textile electrodes are more susceptible to wear and tear, particularly abrasion and oxidation, and require regular replacement. Future work will explore alternative conductive materials that are cheaper and more durable. Despite this limitation, textile electrodes offer a viable, efficient alternative to conventional steel electrodes for ERT applications in difficult terrain.

The toxic properties and bioaccumulation capacity of numerous organic chemicals pose significant threats to environmental and human health. In the Arctic, there is evidence for accumulation processes of banned persistent organic pollutants (POPs) and further pollutants classified as chemicals of emerging Arctic concern (CEACs). Their presence in permafrost-affected soils is due to both their partitioning from the atmosphere to liquid or solid phases, promoted by the cold temperatures prevailing in the Arctic, and to direct emissions from local sources in these sparsely populated areas. The Mackenzie Delta Region, for instance, experienced extensive oil and gas exploration activities from the 1960s to the early 2000s. During this time, drill cuttings and drill fluids were disposed of in large sumps typically excavated adjacent to the well-head, making use of permafrost as natural hydrological barrier to contain the pollutants.

As the Arctic is now warming nearly four times the mean global rate, contaminant remobilization pathways to and within the Arctic are changing. Permafrost thaw may have profound effects on the inherent pollutant sink, including the 233 documented drilling mud sumps in the Mackenzie Delta region. More than half of the constructed sumps, encapsulating significant amounts of drilling fluids, now show major signs of structural failure. With sump cap subsidence and collapse, there is growing concern that organic pollutants such as oil and drilling fluid additives may be released to the environment.

In this study, we analyze soils on and downstream of four selected drilling mud sumps along the Inuvik-Tuktoyaktuk Highway. Through detailed non-target screenings of extractable organic compounds, we investigate the potential presence of various organic contaminants and assess their concentration levels above and below the permafrost table. This research aims to provide a first assessment of potential contaminant dispersion and degradation in a permafrost region impacted by the legacy of gas exploration.

Rockglaciers are distinct morphological indicators for the current and former occurrence of permafrost and act as important debris-transport systems in periglacial environments. For the enhanced use of these landforms as palaeoclimatic indicators, more insights are needed towards landform dynamics, genesis and evolution.

In the European Alps, several attemps have been made in recent years to compile and reconstruct rockglacier ages; by description of flow-lines of horizontal surface velocities (Kääb et al. 1998), by surface-exposure dating (Haeberli et al. 2003, Amschwand et al. 2021), by 14C dating of organic material from ice cores (Krainer et al. 2015), and modeling approaches (e.g. Müller et al. 2016).

In a recent attempt, we follow a multi-method approach to decipher the evolution of rockglacier Murtèl in more detail (surface and depth). The corresponding data result from:

• Monitoring of subsurface deformation

• Geodetic surveys

• Analysis of aerial images

• 14C dating of water-insoluble organic carbon

• Numerical age-layer modeling

Our multi-method approach provides insight into the recent dynamics as well as long-term evolution of rockglacier Murtèl. The combination of recent annual as well as decadal velocities indicates a possible range and temporal variability of creep rates over centuries and millennia. Nevertheless, distributed surface ages derived from surface velocities fit relatively well with the subsurface ages at a single location. Despite the fact that more datings are needed (and expected) from additional depths, the existing ages allow to determine the dominant processes for the genesis and long-term rockglacier evolution after deglaciation on this slope.

Saline permafrost occupies a significant portion of the northern hemisphere along shorelines and coastal permafrost areas. The salt content in this permafrost can lead to freezing point depressions, meaning unfrozen hypersaline material exists at sub-zero temperatures. This can lead to unexpected geomorphological changes, when permafrost temperatures rise above the freezing point, a factor that usually is not implemented in models predicting permafrost thaw.

A rising number of retrogressive thaw slumps (RTS) in Arctic permafrost increases the risk for long-term infrastructure stability. As the behaviour of RTS is hardly predictable, a detailed investigation of the geological setting and the controlling ice availability are often required to make assumptions about their future behaviour. How a variable salt content and a freezing-point depression are influencing the behaviour of RTS is not previously studied. We use a combination of stratigraphic logging, different laboratory analyses and Electrical Resistivity Tomography (ERT) to investigate how saline permafrost impacts RTS development and behaviour.

The goal of the study is to better predict the future behaviour of retrogressive thaw slumps and establish a bundle of techniques necessary to understand the geomorphological impact of saline permafrost.

Cryospheric components in the semiarid Andes of Chile are crucial freshwater sources for both ecosystems and communities. While the changes in glaciers in this region have been extensively documented—showing continuous recession and downwasting—studies and systematic measurements of viscous creep features, such as rock glaciers, which carry ice-supersaturated debris in perennially frozen ground (permafrost), remain limited.

The objective of this study is to quantify and characterize the velocity of rock glaciers (RGV) on 50 morphologically active landforms situated within the Molina River catchment area. This aims to provide enhanced insights into the ongoing changes in mountain permafrost. To achieve this, we employed near-annual very high-resolution images from the Pléiades satellite constellation, captured between 2013 and 2024, obtained from both archive and acquisition modes. Furthermore, the most recent guidelines from the Rock Glacier Inventories and Kinematics (RGIK) initiative were applied, encompassing both geomorphological and kinematic inventory approaches. As changes in RGV can serve as a proxy indicator of the current state of mountain permafrost, extensive measurements were conducted using image co-registration, multi-temporal block adjustments, and feature tracking across the entire dataset.

Preliminary results indicate that the RGV velocities for most of the landforms range between 0.10 and 0.85 m/yr, which is considerably slower than rates observed in other mountain regions. Despite the complex and poorly constrained ground thermal conditions, it has not been possible to establish a clear trend (acceleration versus deceleration) for the study landforms. This study focuses on one of the largest permafrost regions in the Southern Hemisphere and one of the most rock glacier-abundant areas worldwide.

Permafrost thaw releases large quantities of contaminants into the environment. In fact, permafrost soils store nearly twice as much mercury as all other soils, the ocean, and the atmosphere combined. This mercury is vulnerable to release as permafrost thaws and coastlines collapse today and in the future. Contaminants, including heavy metals, persistent organic pollutants and microbiological agents locked in permafrost, are a risk for both human and animal health. Yet the social, physical and health components of permafrost thaw have traditionally been studied in isolation, leading to inadequate policy options that ignore the holistic nature of the threat. There is a need for an integrated and participatory approach to the complex issues at the overlap between climate change, permafrost thaw, infrastructure damage, contaminants, health and wellbeing and for solutions founded on the cultural, natural and social frameworks of local communities.

ILLUQ is an interdisciplinary EU-project rooted in participatory research with local stake- and rightsholders. Its mission is to provide a holistic approach to permafrost thaw, pollution, One Health and well-being in the Arctic and delivering timely products on the threats from contaminant release, infrastructure failure and ecosystem changes to stakeholders. ILLUQ’s endeavor is a direct answer to the pressing needs of communities located on permafrost. It targets the missing link between studies performed by scientists, engineers and consultants in local communities and solutions with local stake- and rightsholders. ILLUQ focuses on three main areas in the Arctic: Svalbard, West Greenland and the Mackenzie Delta area.

In this presentation, we introduce the project and its activities during the 2024 summer expedition along the Yukon Coast. We aim to develop a comprehensive framework for stocks and fluxes of mercury along the Yukon mainland coast and its fate in the nearshore zone of the Canadian Beaufort Sea.

On June 11, 2023, a massive rock avalanche occurred in the Silvretta mountain range near Galtür, Austria, originating from the Southern Fluchthorn summit and releasing approximately 950,000 m³ of rock debris into a snow- and (partially) ice-covered deposition zone. This event resulted in a 19-meter reduction in summit elevation (from 3399 to 3380 m) and a debis flow which flodded the lower Futschöl valley. By integrating historical data, high-resolution airborne laser scans, as well as glaciological, meteorological and hydrological records, we analyze the natural events leading up to the rockfall and its evolution into a debris flow.

Temperature data from nearby weather stations did not reveal significant warming in the weeks before the event. However, strong snowmelt rates and intense rainfall before may have contributed to trigger the event. Additionally, hydrological measurements along the Jamtal river show a peak flow rate consistent in time with the rock avalanche indicating the release of water during the event followed by a runoff reduction due to damming effects in the deposition area. The rock debris first hit the area of a debris-covered glacier, the Fluchthornferner. This same area was covered under ca. 1.4m snow at the time of the impact. The Fluchthornferner has experienced significant retreat since 1850, losing 60% of its area. It disintegrated into several parts and the southern tributary completely vanished in 2018. The ice loss on the main glacier has steepened the glacier's surface slope, as demonstrated by digital elevation models (DEMs) and LiDAR data spanning from 1969 to 2018. Notably, a meltwater thermokarst lake at 2,686 meters contributed to the destabilization prior to the avalanche. The water of the thermokarst lake, together with the snow and ice melted by the energy of the impact contributed to the transition into a debris flow.

Climate change poses a significant challenge to humanity, with its global repercussions threatening economies and livelihoods for future generations. Developing effective strategies to enhance climate resilience through adaptation requires reliable baseline data, including climate observations and the Essential Climate Variables (ECVs) identified by the Global Climate Observing System (GCOS). However, substantial gaps persist in the global climate observing system, especially in high-altitude mountain regions. This issue is particularly pronounced in developing countries, where baseline data is either lacking or at risk to be continued, therefore also increasing uncertainty about the impacts of climate change. Such information is crucial for predicting future changes and devising appropriate adaptation strategies.

Climate change in the mountainous regions of Central Asia significantly affects water resources and increases the frequency and intensity of natural hazards. To address these challenges, the Cryospheric Observation and Modelling for Improved Adaptation in Central Asia (CROMO-ADAPT) project has focused on closing data gaps and strengthening cryospheric monitoring systems, including snow, glaciers, and permafrost. As part of this initiative, new permafrost boreholes have been installed across Central Asia.

Three boreholes, each approximately 30 meters deep, were drilled at sites in Kazakhstan (Zholsalykezen Pass), Kyrgyzstan (Akshiirak), and Tajikistan (Uy Bulak Pass). All boreholes confirmed permafrost conditions and are continuously monitored. Recorded temperatures at 20 m depth are approximately -0.17°C in Kazakhstan, -1.6°C in Kyrgyzstan, and -1.1°C in Tajikistan. Additionally, geophysical surveys have been conducted at these locations and are compared with the borehole data to provide a more comprehensive understanding of permafrost conditions.

Permafrost stores large amounts of mercury (Hg), locking this toxic element in frozen soils across the Arctic. Mercury and its organic form methylmercury, in particular, is a neurotoxin which accumulates along the food chain. With increasing rates of coastal erosion driven by rising air and ground temperatures, Hg is being mobilized and released into the Arctic Ocean. This process does not only threaten local ecosystems but has broader implications, as Hg might be transported over long distances or taken up by marine organisms, posing risks to both wildlife and human health. To better understand such risks, we aim to quantify the amount of Hg that is stored in permafrost and released by coastal erosion along the Yukon Coast, Canada. Samples were taken from various landscape features including permafrost cliffs, active layer, and marine sediments along the Yukon Coast and on Herschel Island-Qikiqtaruk. We analyzed over 70 samples for elemental mercury, organic carbon, nitrogen, and grain-size distribution, and supplemented these results with existing data from previous field campaigns and the literature to create a regional database. Based on these data we will first estimate Hg stocks in the upper permafrost for the Yukon Coast. Combined with coastal erosion rates we will then estimate annual Hg fluxes into the ocean for this region. Together with Hg concentrations in marine sediments our findings will provide a clearer picture of the Hg stocks, fluxes, and its fate along the Yukon Coast. These data are crucial for decision makers and might help to assess Hg exposure to Arctic wildlife and human populations, whose diet largely relies on marine biological resources.

Elevation-Dependent Warming (EDW) in the Indian Himalayas, characterized by accelerated warming at higher altitudes, is increasingly impacting permafrost stability, rock glaciers, and glacier-fed lakes. This study explores the connections between EDW, glacial lake expansion, and the destabilization slopes at high altitudes. The satellite remote sensing-based data has been used to analyze the pattern of surface temperature variability in the central Himalaya at higher altitudes to understand the EDW patterns and their numerous effects as causative factors on high mountain hazards such as glacial lake outburst floods (GLOFs) and snow/ice/rock avalanches. The majority of the hanging glaciers are located at the steep slopes above 5000 m asl in this part of Himalaya which are tremendously vulnerable to the temperature variability. The slope instability in high-mountain regions has very well been linked to increase in temperature and the associated permafrost degradation and/or the increase in frequency/intensity of rainstorm events. Our temperature analysis showed significant variability and a rising trend in recent years during winter and as well annually at elevations above ~4000 m asl. The recent events in the Chamoli region, Kedarnath region, Manasalu region and Dokriani region very clearly presented the evidence of impacts of temperature variability at higher reaches. Further, it has been observed that the glacial lakes are increasing in number and expanding faster at higher altitudes as compared to lower altitudes.

The Arctic is undergoing significant change. Some alarming impacts are more visible, such as decreased ice sheets and sea ice, and others seem to have a more direct impact on people in Central Europe, like landslides or rock fall in the alps due to permafrost warming. However, thawing of Arctic permafrost is mostly taking place in the hidden depths of the ground and nevertheless has a huge impact on greenhouse gas emissions and livelihoods of people living in the Arctic.

The "UndercoverEisAgenten", funded by the Federal Ministry of Education and Research (BMBF), is testing a novel approach to improve observations on thawing permafrost and refine our understanding in Arctic landscape change with the help of citizen scientists. In 2022 and 2024, students from an indigenous school in Aklavik, NWT Canada, worked together with DLR, HeiGIT and AWI researchers to collect high-resolution aerial photographs from drone flights in the Mackenzie Delta. In close collaboration with secondary schools in Germany, these image data were processed and analyzed in small mapping tasks, so called "micro-tasks". Specifically, we asked students in numerous workshops, school visits and mapathons to mark the center of permafrost ice-wedge polygons - with each image mapped by several students. Results demonstrate that Volunteered Geographic Information data closely matches the actual network structure. Our study shows that using the Voronoi characteristics of ice-wedge polygons can simplify the mapping process, enabling citizen scientists to complete the task with high precision and minimal effort. At the same time the “UndercoverEisAgenten” brought the urgent topic of climate change and permafrost thaw into classrooms and hopefully continued science transfer and discussions on climate change beyond the project lifetime.

More information, teaching material and the mapping application can be also found at: https://undercovereisagenten.org/

In 2020, a borehole was drilled into the Schafberg Ursina III rock glacier in the Upper Engadine region of Switzerland and equipped with piezoresistive and temperature sensors (Keller PAA-36XiW level; PT-1000 temperature sensor). These sensors allow continuous, high-resolution monitoring (Bast et al., 2024; Phillips et al., 2023), providing critical insights into subsurface thermo-hydrological processes within the rock glacier. However, the high volumetric ice content complicates data interpretation, as it appears to affect some sensor readings (Phillips et al., 2023).

To address this issue, a series of laboratory experiments were conducted to assess sensor performance in water and ice under controlled conditions. The goal was to develop a method for detecting potential measurement artifacts caused by ice formation near the sensors. In these experiments, the sensors were tested under conditions that mimicked the field environment including sediments and different gravimetric water contents, as well as in tap water, to evaluate their responses to freezing and thawing.

This study combines laboratory and field data from the Ursina III rock glacier to evaluate the limitations of piezoresistive sensors in ice-rich permafrost and explore their potential for accurately monitoring water pressure in sub-zero degree Celsius environments. We will present a methodology developed to identify signals influenced by ice near the sensor, providing a tool for improving the potential of hydrological monitoring in ice- and water-bearing rock glaciers. These analyses aim to improve our understanding of sensor-based hydrological studies in ice-rich permafrost.

Bast, A., Kenner, R., & Phillips, M. (2024). Short-term cooling, drying, and deceleration of an ice-rich rock glacier. The Cryosphere, 18(7), 3141–3158. https://doi.org/10.5194/tc-18-3141-2024

Phillips, M., Buchli, C., Weber, S., Boaga, J., Pavoni, M., & Bast, A. (2023). Brief communication: Combining borehole temperature, borehole piezometer and cross-borehole electrical resistivity tomography measurements to investigate seasonal changes in ice-rich mountain permafrost. The Cryosphere, 17(2), 743-760. https://doi.org/10.5194/tc-17-753-2023

Mountain permafrost degradation due to global warming reduces the stability of steep rock slopes, increasing hazard potential for infrastructure, settlements, and mountaineers. Monitoring these environments continuously remains challenging, but recent studies have demonstrated that seismology can detect both seasonal and long-term permafrost changes with high temporal resolution.

To explore lateral variations in permafrost dynamics at Mt. Zugspitze (German/Austrian Alps), we installed three small seismometer/geophone arrays and a fiber-optic cable for DAS in a tunnel beneath the ridge west of the summit. The seismometers operated for up to two years, while DAS was deployed in campaigns over the same period. We use the cable car operations at the summit as stationary noise sources for cross-correlation calculations, extracting direct and coda waves between the deployment sites and along the fiber-optic cable.

From the seismometer data, we observe significant time-lapse changes in seismic velocity in the western part of the ridge. As freezing begins in fall, seismic velocities steadily increase, but percolating water from snowmelt and precipitation causes velocities to drop again in spring. Despite lower DAS recording quality, preprocessing and cross-correlating with the seismometer data produces high-quality seismic responses. These can be further exploited to pinpoint velocity changes in areas of major freeze-thaw processes, as revealed by electrical resistivity tomography (ERT) studies.

Compared to more traditional methods like ERT, seismology offers both high temporal resolution and spatial insights over larger areas, making it a valuable tool for permafrost monitoring. Its sensitivity to both rock temperatures and cleft water provides additional benefits, as both factors are crucial in permafrost rock mechanics.

Water flows in high alpine rock walls play a crucial role in frost weathering, rock fall and rock avalanche triggering, as well as in permafrost dynamics. Yet, the timing and quantity of water running through bedrock fractures, along with their mechanical and thermal implications, remain poorly understood.

Throughout 2022 and 2023, we monitored water flows in the man-made galleries of the Aiguille du Midi (3842 m) in the Mont Blanc massif. The monitoring system measured water flow rates, conductivity, temperature and fluorescence. Two different fluorescent dyes were inserted in the snow pack on the rock wall above the galleries during winter to assess water flow timing and source, hydraulic conductivity, and fracture connectivity. Surface temperature measurements were also taken at the rock-snow interface to assess the timing of snow melt, and on the rock surface within and around fractures inside the galleries to detect potential thermal effects of water flows. To decipher potential water origins, we also sampled water to perform geochemistry analyses.

The acquired data provide new insights in water flow characteristics, revealingt a seasonal to subdaily dynamic, and suggest that the collected water mixes snowmelt water, rainfall but also permafrost water.

The role of water flow in promoting and triggering rock slope failures in warming permafrost rocks has increasingly been recognized. Still, quantitative assessments of rockwall hydrology remain scarce due to the competitivity of the processes involved and the challenges of field observations. To address this knowledge lack, we combined timeseries of borehole temperature, electrical resistivity tomography (ERT) measurements, and piezometric pressure observed at the permafrost-affected north flank of the Kitzsteinhorn (Hohe Tauern range, Austria). Ground temperature in two deep boreholes revealed abrupt temperature anomalies and long-term regime changes in the periods 2016-2019 and 2020-2024, indicating the occurrence of non-conductive heat fluxes along fractures. ERT observations conducted at 4-hour intervals in winter 2013, monthly in summer 2023, and daily throughout summer 2024 highlight a massive decrease in electrical resistivity of more than one order of magnitude during the thawing season (July-September), indicating infiltration of snowmelt water into the rockwall. These results coincided with periods of high piezometric levels, indicating pressures up to 1.2 bar above barometric pressure, also suggesting widespread water injection within the fracture network. Our study shows that permafrost rocks are warmed more rapidly by percolating water than possible by slow heat conduction and are subjected to high pressure levels - both critical factors predicting rock slope instabilities and failures.

In the Himalayas, thawing permafrost is widely recognized as a major risk for initiating mass movements, influencing hydrological run off or impacting biodiversity. However, information and knowledge on the occurrence and changes of mountain permafrost in the Himalayas are still very scarce or absent in most areas such as Bhutan. In the recently launched CRYO-SPIRIT project, Bhutan and Switzerland are joining hands to initiate permafrost research in Bhutan and to fill this important white spot. The project strategy focuses on three main aspects namely (i) collecting and computing permafrost data using in-situ and remote sensing technologies, (ii) assessing and raising awareness about (future) risks related to permafrost thaw, including the development of adaptation strategies and (iii) building capacity of local researchers to sustain permafrost related monitoring, research and teaching activities in Bhutan.

To assess permafrost, we focus on compiling the first regional map of potential permafrost distribution in Bhutan using in-situ Ground Surface Temperature (GST) measurements and remote sensing-based mapping of permafrost characteristic landforms, in particular rock glaciers. The first CRYO-SPIRIT field campaign took place in autumn 2024 in the vicinity of Thana glacier (Chamkhar Chhu Basin, Bumthang). This site was selected for its proximity to one of the three benchmark glaciers visited annually by researchers from Bhutan’s national center for hydrology and meteorology (thus ensuring the long-term continuation of the measurements) as well as for the existence of an automatic weather station and the presence of identified periglacial landforms. During the field campaign, ground surface temperature loggers have been installed between 4300 m a.sl.(below the lower limit of permafrost) and 5200 m a.s.l. along an elevation gradient and with different exposition.

In this contribution we present the results of the first field campaign of the CRYO-SPIRIT project and intend to foster discussions and potential collaborations with international permafrost experts.

Permafrost is classified as an essential climatic variable (ECV) by the Global Climate Observing System (GCOS) due to its sensitivity to climatic changes. The Swiss Permafrost Monitoring Network PERMOS documents the permafrost in the Swiss Alps since 2000 based on long-term field measurements. The monitoring strategy continuously evolved during the past two decades and today includes three complementary elements: (1) direct observation of ground temperatures, (2) permafrost electrical resistivity to determine changes in ground ice content, and (3) rock glacier velocities, which are considered a proxy to assess the thermal regime.

In this contribution, we discuss permafrost conditions in the Swiss Alps during the hydrological year 2024 with respect to the observations of the past 25 years. We observe striking changes in permafrost conditions for all three observation elements. Most recently, the hydrological year 2024 was characterized by a very warm winter resulting from an early snow cover in autumn 2023 following a hot summer. First results point to the warmest permafrost conditions since the start of the observations revelaed by all observation elements.

The canton of Bern has established a permafrost monitoring network in the Oberland region. This network includes over 100 sites where surface temperatures, subsurface temperatures, geophysical methods, or a combination thereof have been measured and continue to be monitored. The dataset is unique and includes since 2023, for example, the highest-altitude permafrost borehole in Europe, located near the summit of the Jungfrau at 4140 meters above sea level. A systematic analysis of these data has not yet been conducted.

Wisse Schijen is a >40° steep, NE oriented permafrost slope located around 3000 m asl above Randa in Canton Valais, Switzerland. It was equipped with 8 rows of snow nets for avalanche defence in 1991. These structures have been monitored since 1999 to assess their performance in unstable terrain. Two boreholes were drilled to monitor ground temperature and borehole deformation in 2017 and three in-situ GNSS devices were installed in 2015, 2022 and 2024 to measure slope deformation. The active layer is ca. 2.5 m thick and the permafrost is warming rapidly.

The data revealed a deep-seated instability with significant acceleration and change in deformation regime of the slope in summer 2024. Horizontal displacements exceeded 80 cm in 2024, whereas the previous maximum was 50 cm in 2023. UAV-based photogrammetry confirmed these values. Data from an in-situ meteorological station also measuring ground moisture content in 10 cm depth show that the strongest deformation occurred during snow melt after a particularly snow-rich winter. Subsequent notable accelerations in summer 2024 were triggered by strong rainfall. Analysis of the GNSS data and of borehole deformation data shows that the deformation is occurring in at least two different depths: within the blocky active layer and at over 10 m depth within the rock mass. A flat area with glacier ice and long-lasting snow patches at the top of the slope is a source of water during the warm season, with a small stream disappearing into the top of the unstable slope. Water likely plays a key role in the deformation of this slope and to further investigate its contribution we installed a seismic sensor in the slope in 2022 and are planning to drill piezometer boreholes and carry out geophysical investigations.

Landslide processes are a hazard related to steep alpine terrain and are an important driver of alpine landscape evolution. They occur in a wide variety of settings and as a response to various triggering factors. In high alpine terrain processes are strongly influenced by permafrost thawing and glacier retreat driven by climate change. Therefore, rockfall and rockslide processes and activities are studied on a local scale, through the establishment of an in situ rockfall/rockslide laboratory in the Stubaier glacier area in Tyrol (Austria) an area affected by glacier retreat and thawing permafrost at an altitude between 2500 and 3332 m a.s.l. Using a multi-methods and multi-sensor approach, we enable long-term monitoring of rocks slopes affected by permafrost thawing and glacier retreat.The first measuring instruments were installed in summer 2023 and the complete development is planned for fall 2024. Our approach is based on remote sensing campaigns, geological survey, and meteorological data, we intend to achieve a more complete understanding of the involved processes and their interactions.

The drastic climate changes in the Arctic are leading to changes in carbon cycling in permafrost soils that are difficult to predict. Mineralization of organic matter (OM) and release as greenhouse gases depends on both the quantity of organic carbon (OC) and its availability for microbial degradation. Key indicator of microbial degradability are OC/N and ratios of labile to recalcitrant organic compounds.

Our study investigates the relationships between different soil parameters and different indicators of OM quality. The data set includes total OC content, OC/N ratio, alkanes and fatty acids (FA) and ratios calculated from this as well as microbial membrane lipids (PLFA) and CO2 production in incubation experiments. The analyses were performed on samples from the active layer at Svalbard, Siberia, and Greenland, which differ in their climatic conditions and vegetation.

A major difference between sites results from the dense to sparse vegetation cover that is reflected by the OC contents decreasing in the order Greenland > Siberia > Svalbard. Total FA concentrations are related to plant cover in the same way: concentrations are much higher in the densely vegetated soils on Disko Island compared to Svalbard with its sparse vegetation. The non-vegetated Yedoma thaw mounds have very low FA concentrations, so that this parameter is at least a first good reference value for identifying the input of fresh plant material. There is no significant correlation with CO2 production or PLFA concentration for all sites. These parameters are influenced by the water, OC and N content at all three sites.

Different proxies for OM quality show only site-specific correlation with different soil parameters and demonstrate that it is difficult to find indicators of OC turnover in permafrost soils that are applicable to different locations, because of the complex interaction of various soil parameters and climatic conditions.

Mountain permafrost, like permafrost everywhere, is warming due to climate change. Knowledge about the distribution of permafrost is relatively advanced for rock faces and debris accumulations—such as rock glaciers, moraine, and scree—but intermediately steep mountain slopes in permafrost zones, roughly ranging from 40° to 60° inclination, remain poorly understood, despite covering a significant proportion of alpine environments. Given the ongoing degradation of permafrost, improving our understanding of its distribution and structure in such slopes is essential. Intermediately steep slopes often feature highly fractured rock, surface debris, and extended/variable snow cover during winter. These slopes may contain more ice than steep rock walls due to increased water availability from the refreezing of snowmelt, resulting in different thermal and morphological responses compared to steep permafrost rock faces. The complex surface micro-topography in these areas leads to substantial variability in solar radiation and snow distribution over short distances, creating highly variable local thermal conditions and resulting in a complex situation regarding the stability of such slopes.

This project investigates four key sites in the Swiss and French Alps: Mont Fort (3329 m a.s.l.), Pointes du Mourti (3563 m a.s.l.), Cabane de la Dent Blanche (3500 m a.s.l.) in the Swiss Pennine Alps, and Sommet de Bellecôte (3417 m a.s.l.) in Savoie, France. These sites provide a comprehensive view of permafrost conditions in steep slopes across a variety of high mountain environments.

Our data acquisition and monitoring strategies include:

• Recording of surface temperatures

• Borehole temperature measurements

• Repeated electrical resistivity tomography surveys

• Drone-based structure-from-motion photogrammetry

• Snow depth quantification

This five-year PhD project aims to acquire a substantial field dataset to characterise the distribution of permafrost in steep slopes. As the project progresses, the data will be used to model the distribution and evolution of permafrost in such environments.

Permafrost coasts in the Arctic are extremely vulnerable to the effects of global climate change. The increase in sea temperature, the decrease in sea ice extent and longer open-water seasons lead to higher coastal erosion. These erosion rates are among the highest worldwide. This results in significant land loss, both planimetric and volumetric, and leads to a notable reshaping of the coastline. Coastal erosion rates are usually reported in 2 dimensions and focus on the shoreline movement. Few studies have attempted to compute the volumes eroded by coastal retreat. The goal of this study is to connect planimetric and volumetric coastal erosion measurements and to serve as an update of coastal erosion rates in the most recent years on Herschel Island Qikiqtaruk (HIQ) in the Western Canadian Beaufort Sea. LiDAR-derived high-resolution digital elevation models (DEMs) were used to compute volumetric data for the years 2013 and 2023. For the planimetric changes we used digitized coastlines derived from satellite imagery in 2000, 2011 and 2022. Our preliminary results show that the average planimetric erosion ranges between -0.71 and -0.74 [m^2/(m*a)] for the observed periods 2000-2011 and 2011-2022. The volumetric erosion along the entire coastline of Herschel Island Qikiqtaruk experiences a drastic coastal retreat with average values of -33.18 [m^3/(m*a)] whereas the highest values occur along the northwestern, northern and northeastern coastlines of HIQ. This increase can have large implications on the near-shore ecosystems of the island and extensive impacts for the settlement on Herschel Island Qikiqtaruk in the future.

The Murtèl rock glacier in the Engadin is one of the most investigated rock glaciers in the Alps. In 1987 the first borehole recording temperature and deformation data was drilled, and since then two more were drilled in 2000 and one in 2015. This thesis will investigate the temperature and deformation from the 2015 borehole with the aim of improving the understanding of the thermal, hydrological and structural processes responsible for variations in seasonal kinematic response. Rock glacier deformation data with high temporal and high vertical spatial resolution is rare and valuable to understand creep processes. Rock glacier creep exhibits long-term trends related to mean annual temperatures but also seasonal fluctuations for which the dominant controls are still in debate. The deformation and temperature data from the 2015 borehole will be compared with the on-site meteorological station data, GNSS surface velocity and ground surface temperature loggers for years 2016-2023. The method developed aims to provide guidance for future systematic analysis of rock glacier borehole data. Two seasonal phases (cold and warm) are defined based on the presence of the insulating snow cover layer. The detection of the thermal control happens in the warm phase when the presence of high temperatures at depth leads to late summer acceleration. A warm phase after a snow-poor winter is expected to have warmer permafrost conditions which favor high deformation rates and vice versa. The hydrological control is defined by the dynamics of the seasonal melt given by the duration of the spring zero curtain. The structural controls are determined by comparing to a similar study of a structurally different Schafberg rock glacier. Improved process understanding of rock glacier creep will help develop more advanced creep models.

In order to investigate the late Pleistocene permafrost, landscape, and climate dynamics on the eastern side of the Beringian land bridge in the spring and summer of 2024, during the expedition “West Alaska 2024,” field studies were carried out on the Baldwin Peninsula. Holocene thermokarst and cover deposits (MIS 1), late Pleistocene Yedoma Ice Complex deposits (MIS 3/2), and older interglacial and glaciofluvial deposits (likely MIS 5e and older) were investigated. This research complements and connects earlier studies across Beringia, i.e., in north-eastern Siberia, on the Seward Peninsula, near Fairbanks, and in the Klondike.

Frozen sediments and ground ice (ice wedges and intra-sedimental pore and segregated ice) were sampled and described. First analyses of the ice content were carried out during the expedition. Analyses of stable water isotopes of ground ice, stable carbon, and nitrogen isotopes of organic matter, age determination (radiocarbon and optically and infrared stimulated luminescence), determination of organic matter composition, analysis of biomarkers, sediment properties, and studies of paleoecology are currently in progress.

Our poster will present field data (permafrost profiles, sediment, and ground ice properties) and first laboratory results from the expedition near Kotzebue on the Baldwin Peninsula. The external conditions during the two phases of the expedition were excellent. We used snowmobiles in spring, as well as boats and four-wheeled vehicles to reach the outcrops in summer. In Kotzebue, we had very good conditions for sample processing and initial laboratory work, including freezer capacity to keep all the samples frozen.

This study shows the evolution and damming mechanisms of two proglacial lakes situated in a glacier forefield in the Swiss Alps. Initially, the two lakes formed as a single water body at the edge of the Oberferdenglacier, which later split due to the glacier's progressive retreat. As the glacier receded, it left behind a basin that now repeatedly fills with meltwater during the early thawing season. Over the summer, the lake gradually drains, eventually emptying by late summer. To investigate these processes, a combination of Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT), and remote sensing techniques was employed. The aim was to determine whether ice, bedrock, or moraine deposits contribute to the lakes' damming and to understand the mechanisms governing their seasonal drainage patterns. GPR and ERT surveys provided high-resolution imaging of subsurface structures as well as insights into the properties of the damming materials. Remote sensing data from 2018 to 2023 enabled the monitoring of seasonal changes in the lakes, capturing their dynamic evolution in response to glacial retreat. The results indicate that the interplay between permafrost, moraine deposits, and bedrock significantly influences the formation, filling, and draining cycles of these proglacial lakes. This study contributes valuable insights into how glacier retreat shapes proglacial environments and enhances our understanding of glacial lake dynamics, which can aid in assessing potential hazards, such as glacial lake outburst floods (GLOFs), in similar glacial settings.

Continental shelves of the Arctic Ocean are undergoing major changes due to global warming. Increased river discharge, deeper permafrost thaw and intensified coastal erosion are releasing large amounts of previously frozen carbon. Despite these changes, sedimentation rates and the amount of permafrost carbon buried on the shelf remain poorly understood. This study focuses on the quantification of sedimentation rates, carbon fluxes and burial processes on the Canadian Beaufort Shelf. Estimating carbon burial is challenging due to the limited availability of data on modern sedimentation rates. The CASCADE database (Martens et al. 2022) provides an average mass accumulation rate of 0.466 g/cm²/year based on a limited number (n=16) of 210Pb derived estimates for modern sedimentation rates. On longer timescales the spatial variability in carbon burial rates was determined by seismic imaging of Holocene sediment thicknesses (Macdonald et al. 1998), revealing considerable heterogeneity across the Canadian Beaufort Shelf. Therefore, key questions are 1) whether sampling density of modern sedimentation rates sufficiently captures spatial variability across the shelf, and 2) whether the seismically derived Holocene estimates accurately capture modern sediment deposition patterns in the context of ongoing climate change. In fall 2021, sediment cores were taken at 25 sites along five transects on the Beaufort Sea Shelf. Based on measurements of total organic carbon, 210Pb and 137Cs, and the grain density of these cores, sedimentation rates and organic carbon fluxes along the shelf were calculated. By comparing local sedimentation and carbon burial rates, this study aims to improve our understanding of the fate of permafrost carbon on the Canadian Beaufort Shelf.

In the continuous permafrost zone, thermokarst processes are altering and accelerating as the climate changes. Surface subsidence is accelerating and thermokarst lakes are draining, while gullies are expanding and thaw slumps are widening. On the Baldwin Peninsula in West Alaska, such processes are evident and have direct consequences for the local environment as well as the city of Kotzebue. Furthermore, these landscape dynamics have far-reaching effects on biogeochemical cycles, as microbial activity in thawed sediments of thermokarst landforms decomposes organic matter and releases greenhouse gases, further contributing to global warming.

To investigate these processes, sediment cores were collected in March 2024 along two transects that extend from upland areas through thermokarst disturbances into the near-shore zone of the Kotzebue Sound. Taliks were identified and sampled in two thermokarst lakes, a semi-drained lake, and a drained lake basin. These unfrozen sediments are of particular interest concerning organic matter decomposition and greenhouse gas production. A one-year long incubation experiment coupled with pre- and post-incubation n-alkane biomarker analyses on the sediments, aims to decipher organic matter patterns and potentials. First findings from this laboratory work will be presented at the 15th DACH Permafrost Conference.

Global warming provokes permafrost thawing that can lead to local landscape alteration and damage or destruction of infrastructure. Implementation of protective measures is therefore necessary to avoid incidents and damage. Existing methods for thermal stabilization of permafrost are not directly applicable to the particular conditions of the Alps. Passive techniques generally lack the ability to rapidly and effectively stabilize the soil, while active methods remain costly and are not yet fully optimized. Knowing these challenges, a novel solar-powered thermal stabilization system has been designed. It utilizes both passive and active methods and allows effectively protect Alpine permafrost and the most vulnerable infrastructure built on it from the impacts of global warming. To assess the effectiveness of thermal stabilization system, we conducted numerical simulations using the SNOWPACK model, focusing on the Schilthorn (Switzerland, 2900 m a.s.l.) site in Switzerland. In this modeling we performed the various simulations that included the thermal stabilization systems components to evaluate their impact on ground temperature. And the comparison with natural conditions showed the efficiency of thermal stabilization in different combinations. The designed laboratory-scale demonstrator represents the permafrost sample. It includes the components of solar-powered thermal stabilization system components, such as cooling pipes that forms a cold barrier layer, and solar panel that reduces radiative and turbulent heat input, and powers the system. The embedded sensors are monitoring temperature, soil moisture, and heat flux in the permafrost sample. It provides practical insights and study the heat transfer in the sample under different controlled conditions. Results indicate that the barrier layer effectively prevents heat transfer into deeper soil layers, successfully maintaining a frozen layer around the cooling pipes throughout the experiment. Experimental studies, numerical modeling, and optimized engineering allows to design an effective thermal stabilization system for protection of mountain infrastructure.

Boreal forests, which cover almost a quarter of the continuous Arctic permafrost, play a crucial role in stabilizing permafrost by regulating heat and water fluxes between vegetation, the ground, and the atmosphere. However, climate change, along with shifts in precipitation regimes, permafrost conditions, forest composition and density, poses a significant threat to this tightly coupled system, potentially disrupting key ecosystem functions.

We investigate how forest cover influences the thermal and hydrological conditions of permafrost using a numerical land surface model called CryoGrid, equipped with a multilayer canopy module. This provides a comprehensive parameterization of fluxes from the ground, through the canopy, up to the roughness sublayer. The implementation of this roughness sublayer allows the representation of different canopy structures and their impact on the vertical heat and moisture transfer. Storyline simulations reveal that forest canopies exert strong control over the ground's thermal regime, primarily through shading, altering snow cover dynamics, and inhibiting turbulent fluxes. These effects collectively cool permafrost, leading to shallower active layers. Furthermore, simulations including excess ice, have shown that forest covers slow ground ice melt by up to 7 years. Forest thereby delays thermokarst formation onset by 3 to 18 years, depending on ice depth and climate scenario, and further provides a significant buffer against extreme weather events.

Changes in forest cover—such as anthropogenic and natural forest loss (through logging, forest fires, or pests), densification, or shifts in dominant species—alter hydrothermal conditions, such as the active layer depth, locally causing either soil drying or wetting. The research underscores the importance of local, detailed models to understand the complex dynamics and highlights how forest disturbances and climate change may lead to significant ecosystem shifts, threatening permafrost persistence and carbon storage across boreal permafrost landscapes.

Mountain permafrost research focuses on thermal, physical, kinematic and hydrological processes in response to climatic changes. These environments are believed to contain little organic matter. However, organic carbon could originate from past soils that developed during warmer Holocene periods. Yet, there is a lack of studies investigating if and how carbon is stored and released upon mountain permafrost warming and thawing.

Here, we present in-situ CO2 fluxes combined with an incubation experiment of ice-bearing permafrost samples examining potential CO2 release upon thaw. The samples were taken during drilling campaigns in the canton Valais (Eggishorn) and Grisons (rock glacier Muragl), Switzerland. Additionally, substrate samples were collected from the active layer of various rock glaciers in Grisons, at a depth of ca. 30 cm below a layer of rocks. These possibly represent remnants of soils from warmer climates.

In-situ surface CO2 fluxes were generally negligible but detectable from the substrate in the active layer. In support, first measurements of total organic carbon (TOC) concentrations in unfrozen substrates from the drillings are exceptionally low, ranging between 0.02 and 0.2%. In contrast, first results for the active layer substrate shows a TOC concentration of 0.9 to 1.8%. Therefore, we expect C mineralisation rates in permafrost samples to be close or beneath the detection limit. Frozen samples will be pre-thawed before filtering alongside the watery samples. The water samples will be analysed for their chemistry, while the moist substrate samples will be incubated at room temperature. Afterwards, samples will be analysed for texture, TOC and 14C analysis.

Mountain permafrost is assumed to contain very little organic carbon. Our first results support this assumption, with substrates close to the surface showing the highest TOC concentrations. Laboratory incubation experiments will give insight into the relevance of carbon cycling in future warmer mountain permafrost.

Permafrost is a key component of the Earth's cryosphere and plays a critical role in regulating global climate systems. Recent scientific studies reveal that permafrost thaw is occurring at a faster rates than previously projected. New data also suggest that carbon release from thawing permafrost could accelerate significantly by the mid-21st century. These findings are expected to play a central role in the IPCC’s upcoming seventh assessment report. The increasing emissions of greenhouse gases, particularly methane and CO₂, from permafrost regions pose a substantial threat to global climate targets, potentially amplifying warming through a positive feedback loop. However, accurately predicting permafrost carbon emissions remains complex, yet crucial for refining global climate projections and formulating mitigation strategies.

This presentation aims to explore and discuss the intersection of permafrost research with international, multinational, and national climate policies, including the Paris Agreement, focusing on mitigation strategies aimed at preventing unleashed releases of greenhouse gases, irreversible impacts on ecosystems, and socio-economic risks from thawing permafrost. The role of the German Federal Environment Agency (Umweltbundesamt, UBA) in addressing these issues will also be discussed. This includes its involvement in research initiatives, policy recommendations, and collaboration with multinational and international bodies to monitor permafrost regions and promote sustainable climate actions. By addressing both the scientific and policy dimensions, this presentation aims to provide a comprehensive overview of the challenges posed by permafrost thaw and the international efforts to mitigate its impact in the context of global climate governance.

Fremri-Grjótárdalur is a hanging valley in the mountainous region of Northern Iceland, on Tröllaskagi, a dissected peninsula within the ‘Subpolare Zone’ and influenced by a cold maritime climate. Today the valley can be characterized by huge rock accumulation bodies in its cirque, which lies in the zone of recent discontinuous permafrost. Despite numerous attempts to identify and interpret such bodies in Iceland there still is an ongoing debate about their origin as well as the possibility of ice buried beneath their rocky surface and its type.

In combination with the observed increased gravitational mass movements on mountain slopes, the aim of this study is to identify geomorphological features and processes to determine the predominant geomorphodynamics today and in the past to contribute to a better understanding of landscape evolution and inferring likely changes in their nature within changing climate and the issue of permafrost degradation.

The results show that detailed geomorphological mapping can help to determine the current geomorphodynamics of the valley and to identify rock glaciers of various types and origin. As rock glaciers are regarded as reliable permafrost indicators, the recent and past distribution of permafrost was assessed by identifying intact and relict forms. Furthermore, findings were obtained that refute the sole existence of debris-covered glaciers and instead point to the coexistence of glacier-derived and talus derived rock glaciers of periglacial origin in close vicinity.

However, as geomorphological mapping is limited to the external appearance, it is difficult to draw conclusions about the internal structure of these rock glaciers. It is therefore necessary to use other methods such as geophysics to verify the assumptions made in this study. Due to the increasing gravitational movements in Iceland, it would also be important to focus on so-called molards and other indicators of permafrost degradation in the future.

A freestanding rock pillar with a volume of approx. 20 cubic meters on the Matterhorn Hörnligrat ridge failed on 13 June 2023. Based on comprehensive multi-method monitoring of the pillar and the surrounding ridgeline environment starting in 2008, we perform a detailed analysis of the progressive failure from kinematic precursors to seismic response. The rock pillar was instrumented with a differential GNSS station and inclinometers, showing a strong seasonality in displacement rates and an acceleration with regime change starting in 2022 almost two years prior to the failure. The pillar was in the field of view of a stationary camera, whereby the time-lapse images show a visually apparent acceleration two weeks before the collapse. Seismic precursors and response were characterized employing three seismometers in the vicinity. Weather data as well as permafrost ground temperatures enable us to characterize the temporal variation and identify anomalies at the site. The data analysis suggests that snowmelt water percolating into frozen fractures acts as the main driver for the strong seasonality in displacement patterns observed, eventually resulting in failure. This is supported by controlled laboratory experiments using rock samples from the Matterhorn site and thermo-mechanical modeling.

To better understand the complex dynamics of landforms and their assemblages in environments conditioned by glacial and periglacial processes, this study seeks to foster the use and application of a multi-method and multi-disciplinary 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 close-range UAV remote sensing techniques, as well as in-situ GNSS 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 perennially frozen back-creeping push moraines, a glacier forefield-connected rock glacier, and a debris-covered glacier tongue. The strongest morphological and surface elevation changes, which are partly due to ice melt-induced subsidence, have been observed in areas where glacier ice 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, the rock glacier rooting zone, and the margins of the debris-covered glacier tongue. This decrease is likely to be the result of an increased water-to-ice ratio due to permafrost degradation, as well as thinning and melting of massive ice from glacial origin. In the debris-covered glacier tongue, resistivity changes are the smallest, which is likely due to its properties, hindering water infiltration within the cold ice body.

Large herbivore activity has shown to influence permafrost temperature and Arctic soil carbon storage, leading to higher soil carbon stocks under heavy grazing influence. However, distinguishing between organic material deposited by the animals, and preserved soil organic matter as a result of lowering soil temperature is difficult, specifically regarding rather fresh material where radiocarbon dating is not possible. We tested measuring lipid biomarkers on Arctic soil samples exposed to various degrees of grazing, both from permafrost and seasonally frozen deposits, looking at n-alkanes and n-alcohols, trying to identify the degree of OM degradation within these samples. Results showed that soil OM was less degraded at sites with heavy grazing impact, more clearly in permafrost-affected deposits. This shows the OM-stabilising effects of lower ground temperatures, as well as a positive impact of large herbivore activity on Arctic soil carbon storage. First implications for future Arctic land use can be derived from this, but a thorough assessment with larger sample sets from circumpolar study sites is advised.

The age of wetlands in Arctic drained lake basins is a strong predictor of basin ecology and biogeochemical cycling, particularly because of changes in local hydrology over time. Drained lake basins frequently contain peat-forming wetlands, storing large amounts of carbon and nitrogen. Estimations of how thawing and mobilization vs immobilization of permafrost carbon, nitrogen, but also of contaminants such as mercury, contribute to global budgets and should therefore include information on the spatio-temporal distribution of drained lake basins and their age. We present the first database of lake drainage ages covering lowland regions from northern Siberia, across Alaska to the Canadian Arctic. We are using this data to highlight carbon, nitrogen and mercury stocks in a regional subset of the drained lake basins. We cored 124 drained lake basins and used radiocarbon dating of terrestrial peat that formed directly above lacustrine sediments as an estimator of the beginning of post-drainage terrestrial conditions. We assessed the quality of the dates and the stratigraphic, sedimentologic or biogeochemical identification of drainage events for each basin. We then conducted a comprehensive literature study to include > 100 published drainage ages. In this way we will provide a region-wide quantification of drained lakes. We found that nearly all basins drained during the Holocene, and >90 percent of our studied basins drained after 3000 BP. On the other hand, we could prove that individual basins may exist as peat-forming wetlands for many millennia, including wetlands that existed since the late Pleistocene. Our database can be used to quantify carbon and nitrogen stocks as well as mercury stocks in peat from drained lake basins in Arctic lowlands. For the first time, the regional spatial scale and the Holocene time scale will ensure representative information for this highly relevant and abundant permafrost landform.

Seismic slope processes refer to the interaction between seismic waves and slope stability. As they may be more relevant for snow avalanche triggering than earthquakes, avalanche risk zoning considers information about possible seismic events and is therefore of high importance.

To solve this problem, mathematical modeling of physical and mechanical processes in snow and fuzzy sets was applied. The possibility of snowslip occurrence is estimated with the help of information on precipitation, air temperature, the thickness of snow cover, density of snow, angle, and length of slope. In addition, a deterministic methodology for the observation of earthquakes was developed.

Based on the current Canadian Building Code describing the earthquake as a stochastic process, we calculate the earthquake intensity, location, and probability of occurrence. The acceptable probability of an accident death is 0.000001 (Jonkman, 2003). Considering the actual number of seismic avalanche victims, we calculate the acceptable probability of a temblor capable of triggering this hazardous phenomenon by solving this stochastic problem with the Monte Carlo Method.

Avalanche risk zoning, based on such an approach, enables the preparation of maps providing an increased safety level and preventing loss of life and property damage.

References

Jonkman S. E. An overview of quantative risk measures for loss of life and economic damage / S. E. Jonkman, P.H.A.J.M. van Gelder, J.K. Vrijling // Journal of Hazardous Materials. – A99 (2003). – P. 1 – 30.

In the eastern Swiss Alps, discontinuous alpine permafrost exists roughly above about 2400 m a.s.l., and various aspects of the mountain permafrost and in particular rock glacier permafrost have been intensively investigated for a long time. However, sporadic and isolated permafrost patches can also exist below the timberline, in shaded locations and under special environmental conditions, as in the Bever valley where a permafrost occurrence at low altitude (1800 m a.s.l.) below the timberline, which is currently between 2200 m and 2300 m a.s.l., has been confirmed and characterized (Kneisel et al., 2000). Even then, it was assumed that the occurrence of permafrost is a result of the interaction of climatic conditions, topography and surface and subsurface properties which are interrelated.

At this subalpine site with permafrost, the complex interrelationship between different environmental factors has therefore been investigated in more detail in recent years using an integrated approach that combines 2D and 3D near-surface geophysics, soil mapping and surface and subsurface temperature monitoring. The objectives of this approach were to explore the extension of isolated permafrost bodies and to relate this to surface parameters such as humus forms and other external factors. With this integrative approach, interdependencies between surface (soil properties and humus forms) and subsurface factors (ground thermal regime and frozen ground conditions) could be independently analysed. Although time-consuming, 3D electrical resistivity imaging demonstrated its ability for precise permafrost mapping on a small scale.

This contribution summarizes the results of our research and shows the methodological developments during this 25-year research period that now allow multidimensional characterization of the near-surface subsurface, and additionally shows and discusses the now available multi-year temperature data from near-surface temperature loggers and two shallow boreholes.

Seasonal storage of liquid and frozen water in high-mountain catchments will play an increasingly important role as a hydrological buffer in rapidly deglaciating mountains, sustaining streamflow during late-summer dry phases after completion of the snowmelt. Depending on the local topo-climatic conditions, these catchments can be (partly) underlain by permafrost. However, below-ground water pathways and water/ice storage changes are currently poorly characterized in high-mountain catchments because field data with sufficient resolution to capture the spatial variability are sparse. Among geophysical techniques, time-lapse gravimetry stands out as a method that is directly sensitive to the target quantity, mass (density) distribution changes, at an appropriate spatial scale. Time-lapse gravimetric surveys have successfully quantified groundwater storage changes in high-mountain catchments, but have never been deployed on mountain permafrost, notably rock glaciers.

33 years after pioneering gravimetric investigation on Murtèl rock glacier (D. vonder Mühll & E. Klingelé), we return to the site with a state-of-the-art relative spring gravimeter (Scintrex CG-6 Autograv) able to resolve water/ice storage changes at the few μGal range (corresponding to <10 cm water equivalent). First, we present results from repeat gravimetric surveys, complemented by drone-based photogrammetry, that we carried out in early and late Summer 2024. We observed significant, spatially variable gravity changes attributable to the seasonal ice loss in the coarse-blocky active layer. These changes were hinted at, on the point scale, by subsurface stake measurements and energy budget calculations. Second, we compare our data with the 1991 data. Finally, we discuss the strengths and limitations of time-lapse gravimetry in complex mountain permafrost terrain, including challenges related to the decomposition of the temporal gravity signal to different water and rock mass distribution changes.