Dr. Marcia Phillips

Die Veränderungen im alpinen Permafrost finden meist im Verborgenen statt, haben aber zunehmend bedeutende Konsequenzen für die Berggebiete. Im letzten Jahrzehnt sind in den Schweizer Alpen die Permafrosttemperaturen um bis zu 1 °C angestiegen, die Auftauschichten sind um mehrere Meter mächtiger geworden, im Boden hat das Eis ab- und der Wassergehalt zugenommen und die Blockgletscher haben sich schneller talwärts bewegt als zu Beginn der Messungen vor gut 20 Jahren. Diese grossen Veränderungen im Untergrund bedrohen Hochgebirgsinfrastrukturen und führen zu einer Zunahme von Naturgefahren wie Felsstürzen und Murgängen. In diesem Beitrag beschreiben wir die wichtigsten Mechanismen, die immer schnelleren Veränderungen im Permafrost in der Schweiz und die Herausforderungen, die sich daraus für den Kanton Bern ergeben.

Hidden ice in the Swiss Alps: permafrost is thawing faster
Changes in mountain permafrost are mostly taking place invisibly, but can have increasingly important
consequences for mountain regions. In the past decade, permafrost temperatures in the Swiss Alps increased by up to 1 °C , the active layers thickened by several metres, the ground ice content decreased and the water content increased, and rock glaciers were creeping faster than at the beginning of the measurements more than 20 years ago. These important changes compromise the stability of high mountain infrastructures and lead to an increase in natural hazards such as rockfalls and debris flows. In this contribution, we describe the most important mechanisms, the accelerating changes in permafrost in Switzerland and the resulting challenges for the Canton of Bern.

According to various projections, climate change will alter the disposition for alpine mass movements, as well as their dynamics and the interaction of gravitational processes in process cascades. This will change the risks that people living in mountain regions are exposed to. The research program CCAMM - Climate Change Impacts on Alpine Mass Movements – initiated by the Swiss Federal Institute for Forest, Snow and Landscape Research WSL, fosters inter- and transdisciplinary research and thus addresses a socially relevant question and provides an important contribution to climate change adaptation of society. In this contribution, we provide an overview of the 22 projects and the envisioned outreach activities in 2025.

Observations in the European Alps show a long-term rise in rock glacier velocities, which is often associated with increased air and ground temperatures and, more recently, water content. Long-term rock glacier acceleration is superimposed by a high interannual variability of the velocity with a particular gap in the quantitative assessment of the role of water in rock glacier kinematics and the factors leading to short-term rock glacier deceleration.
To address this research gap, we drilled three vertical boreholes in the Schafberg rock glacier, Swiss Alps, in August 2020. We documented their stratigraphy and equipped one of the boreholes with temperature sensors and piezometers and the other two with cross-borehole electrodes for electrical resistivity tomography measurements. Rock glacier velocities were determined using repeated terrestrial laser scans. Using data from an additional borehole and nearby weather stations and ground surface temperature sensors, we analysed the interactions between meteorological and subsurface conditions during a rock glacier deceleration period, from January 2021 to July 2023.
Our findings show that a lowering of the water content in rock glacier shear horizons is crucial for interannual rock glacier deceleration. The impact of the snowpack, both as an insulator and as a water source, is significant for rock glacier kinematics. Winters with little snow and relatively dry summers appear to be ideal for rock glacier cooling and drying, leading to deceleration. Summer heat waves have limited impact on rock glacier velocity if they are preceded by snow-poor winters.
Our study uses an innovative combination of borehole data to gain insights into rock glacier temperatures and water contents, allowing us to detect relative changes in ice and/or water contents in ice-rich permafrost. The monitoring techniques used have the potential to contribute to a better understanding of the main drivers of rock glacier kinematics and water availability.

The spatial and temporal distribution of Alpine snow is a sensitive gauge of environmental change. While understanding past snow dynamics is essential for reconstructing past climate and forecasting future trends, reliable snowpack data prior to the instrumental record are scarce. We present a novel pairing of cosmogenic paleothermometry and luminescence photochronometry which constrain the temperature and insolation history of bedrock outcrops at the Gotthard Pass, Switzerland, over the last ∼15,000 years. By coupling these results with cosmogenic ¹⁴C-¹⁰Be chronology and modern in situ rock thermometry, we infer a ∼70-day reduction of snowpack at the topographic mid-slope. Our data indicate stable environmental conditions throughout the Holocene, followed by a 6.6 ± 2.9°C increase of ground surface temperature, coeval with an order-of-magnitude or more increase in ground surface insolation. Bracketing the onset of these changes between 1504 and 1807 CE, our findings tie the snowpack decline with the onset of human industrialization.

Mountain permafrost, constituting 30% of the global permafrost area, is sensitive to climate change and strongly impacts mountain ecosystems and communities. This study examines 21st century permafrost warming in European mountains using decadal ground temperature data from sixty-four boreholes in the Alps, Scandinavia, Iceland, Sierra Nevada and Svalbard. During 2013–2022, warming rates at 10 metres depth exceed 1 °C dec⁻¹ in cases, generally surpassing previous estimates because of accelerated warming and the use of a comprehensive data set. Substantial permafrost warming occurred at cold and ice-poor bedrock sites at high elevations and latitudes, at rates comparable to surface air temperature increase. In contrast, latent heat effects in ice-rich ground near 0 °C reduce warming rates and mask important changes of mountain permafrost substrates. The warming patterns observed are consistent across all sites, depths and time periods. For the coming decades, the propagation of permafrost warming to greater depths is largely predetermined already.

Am 14. April 2024 um 06:56 Uhr ereignete sich in der Westflanke des Piz Scerscen (Berninamassiv, Engadin, Graubünden) auf einer Höhe von 3640 m ü. M. ein grosser Bergsturz. Rund 5.5 Millionen m³ Fels und Gletschereis lösten sich, stürzten auf den darunter liegenden Vadret da Tschierva und rissen in der Sturzbahn eine dicke Schneedecke und grosse Mengen Gletschereis mit sich. Dieses Gemisch aus Gestein, Eis und Schnee floss über das Gletscherplateau, durch die darunterliegenden Eisfälle und zwischen den Seitenmoränen des Gletschers hinunter und erzeugte eine grosse Staubwolke, bevor es sich auf rund 2100 m ü. M. im Val Roseg, fast 6 km vom Anriss ablagerte. Das Ereignis forderte glücklicherweise keine Opfer und verursachte keine Infrastrukturschäden. In diesem Bericht beschreiben wir die Bedingungen, die zum Zeitpunkt des Ereignisses herrschten und nutzen die verfügbaren Informationen, um die Prozesse zu analysieren, die vor und während des Ereignisses stattfanden.

The degradation of mountain permafrost is well documented at many Alpine sites. Geophysical techniques have been intensively used to monitor these sites, since permafrost degradation is not only a proxy of climate change and global warming but also a possible source of slope instabilities and triggering of mass movements. While the use of non-invasive geophysical techniques is promising, the interpretation of different geophysical results can introduce ambiguities in defining the investigated subsoil and often does not lead to a quantitative estimation of the internal permafrost constituents (rock matrix, ice, liquid water and air contents). To overcome these limitations, we applied an optimized joint inversion approaches of electrical resistivity and refraction seismic tomography datasets collected at two Swiss rock glaciers (Schafberg - Canton Grisons, and Ritigraben - Canton Valais). Firstly, to improve the structural interpretation of the frozen near subsurface, we performed a structurally coupled cooperative joint inversion, optimizing the coupling parameters. Subsequently, we used the petrophysical joint inversion to quantify the composition of these mountain permafrost substrates, optimizing the numerical and petrophysical parameters. The obtained results agree with field observations and the borehole data collected at these two sites, opening new perspectives for the future quantitative monitoring of permafrost constituents.

A novel combination of borehole temperature, borehole piezometer and cross-borehole electrical resistivity tomography (ERT) data is used to investigate changing ice and/or water contents in the creeping ice-rich Schafberg rock glacier in the Eastern Swiss Alps. Instrumentation techniques and first results are presented. The rock glacier ice is close to its melting point, and the landform has locally heterogeneous stratigraphies, ice and/or water contents and temperature regimes. The measurement techniques presented continuously monitor temporal and spatial phase changes to a depth of 12gm and should provide the basis for a better understanding of accelerating rock glacier kinematics and future water availability.

Monitoring mountain-permafrost temperatures in boreholes is challenging regarding the resilience and long-Term temperature stability of the sensor systems. Whilst resistance thermistors boast a high accuracy, they are prone to drift when exposed to moisture, pressure or cable strain. Supplementing or replacing them with digital bandgap temperature sensors requires careful analysis of the sensor performance. We carry out a first comparison of two temperature sensor systems under field conditions in mountain permafrost at 15 identical depths in 1 borehole. Temperature values, sensing delays and noise levels are compared and discussed.

Monitoring of the periglacial environment is relevant for many disciplines including glaciology, natural hazard management, geomorphology, and geodesy. Since October 2022, Rock Glacier Velocity (RGV) is a new Essential Climate Variable (ECV) product within the Global Climate Observing System (GCOS). However, geodetic surveys at high elevation remain very challenging due to environmental and logistical reasons. During the past decades, the introduction of low-cost global navigation satellite system (GNSS) technologies has allowed us to increase the accuracy and frequency of the observations. Today, permanent GNSS instruments enable continuous surface displacement observations at millimetre accuracy with a sub-daily resolution.
In this paper, we describe decennial time series of GNSS observables as well as accompanying meteorological data. The observations comprise 54 positions located on different periglacial landforms (rock glaciers, landslides, and steep rock walls) at altitudes ranging from 2304 to 4003 ma.s.l. and spread across the Swiss Alps. The primary data products consist of raw GNSS observables in RINEX format, inclinometers, and weather station data. Additionally, cleaned and aggregated time series of the primary data products are provided, including daily GNSS positions derived through two independent processing tool chains.
The observations documented here extend beyond the dataset presented in the paper and are currently continued with the intention of long-term monitoring. An annual update of the dataset, available at 10.1594/PANGAEA.948334, is planned. With its future continuation, the dataset holds potential for advancing fundamental process understanding and for the development of applied methods in support of e.g. natural hazard management.

Im Zuge des Klimawandels kann auftauender oder sich auf nahe 0°C erwärmender Permafrost zu einer Häufung von Felsstürzen in steilem Gelände führen. Diese Studie hat deshalb steile Felshänge des Wallis in einem Temperaturbereich von -3°C bis 0°C auf ihr Gefährdungspotenzial für tiefer liegende Infrastrukturen untersucht. Dazu wurde die Präsenz von sensibler Infrastruktur im Gefährdungsbereich ebenso berücksichtigt wie die aus mehreren Einzelkriterien zusammengesetzte Wahrscheinlichkeit für Sturzereignisse. Zusammen ergeben beide Faktoren einen Risikohinweis für jeden Steilhangsektor im betreffenden Bodentemperaturintervall. Auf Grundlage dieses Risikohinweises zeigt sich, dass sich die potenzielle Gefährdung durch grosse Felsstürze aus warmem Permafrost auf 89 Standorte im Kanton Wallis beschränkt. Für diese Standorte wurde in Abhängigkeit des Risikos eine Rangliste erstellt, welche es den Naturgefahrenverantwortlichen ermöglicht, einen Fokus auf diese Gebiete zu legen sowie mit präventiven Massnahmen und Vorkehrungen eine Gefahrensituation frühzeitig zu erkennen.

Rising air temperatures and increasingly intense precipitation are being observed in the Swiss Alps. These changes strongly affect the evolution of the temperature regime and the dynamics of mountain permafrost. Changes occur at different rates depending on ground ice content. Long-term monitoring reveals progressive warming and degradation of permafrost and accelerating rock glacier velocities. This study analyses changes occurring in ice-rich (excess-ice) and ice-poor mountain permafrost in Switzerland between 1997 and 2019 on the basis of ground temperature and rock glacier dynamics measurements carried out by the WSL Institute for Snow and Avalanche Research SLF at seven sites. Long-term borehole data indicate an increase of ground temperatures at all depths, in particular at ice-poor and nearly snow-free sites. Active layers are thickening at most sites and prolonged periods of active layer thaw are observed. Long autumn zero curtains are observed in ice-rich permafrost, possibly leading to an overall acceleration of rock glaciers. All these changes point towards ongoing permafrost warming and permafrost degradation in future.

Temperature measurements in boreholes are the most common method allowing the quantitative and direct observation of permafrost evolution in the context of climate change. Existing boreholes and monitoring networks often emerged in a scientific context targeting different objectives and with different setups. A standardized, well-planned and robust instrumentation of boreholes for long-term operation is crucial to deliver comparable, high-quality data for scientific analyses and assessments. However, only a limited number of guidelines are available, particularly for mountain regions. In this paper, we discuss challenges and devise best practice recommendations for permafrost temperature measurements at single sites as well as in a network, based on two decades of experience gained in the framework of the Swiss Permafrost Monitoring Network PERMOS. These recommendations apply to permafrost observations in mountain regions, although many aspects also apply to polar lowlands. The main recommendations are (1) to thoroughly consider criteria for site selection based on the objective of the measurements as well as on preliminary studies and available data, (2) to define the sampling strategy during planification, (3) to engage experienced drilling teams who can cope with inhomogeneous and potentially unstable subsurface material, (4) to select standardized and robust instrumentation with high accuracy temperature sensors and excellent long-term stability when calibrated at 0°C, ideally with double sensors at key depths for validation and substitution of questionable data, (5) to apply standardized maintenance procedures allowing maximum comparability and minimum data processing, (6) to implement regular data control procedures, and (7) to ensure remote data access allowing for rapid trouble shooting and timely reporting. Data gaps can be avoided by timely planning of replacement boreholes. Recommendations for standardized procedures regarding data quality documentation, processing and final publication will follow later.

The landscape above Pontresina in the Eastern Swiss Alps is characterized by mountain peaks reaching around 3,000 m a.s.l, steep rock walls, ice-bearing scree slopes and dynamic rock glaciers in a corrie - all located above a precipitous gully leading down to the village. A strong visual impact is caused by the presence of over 15 km of avalanche defence structures and a large retention dam. These protection measures were progressively built over the past 130 years. The most recent ones are specially adapted for unstable permafrost conditions and to provide protection against both avalanches and debris flows triggered in over-steepened ice-bearing terrain. The Foura da l’Amd Ursina site (also known as Schafberg) above Pontresina displays the ideal implementation of research results in the development of practical solutions against natural hazards in a mountain environment undergoing climate-related changes.

Since rock glaciers are believed to be more resilient to climate change, water stores therein may become important water reservoirs in future, in particular in dry regions, which currently rely on glacial runoff. In order to estimate and evaluate the future runoff potential from permafrost and rock glaciers, distributed runoff models suitable for high Alpine catchments are needed. An extension to the distributed Glacier Evolution and Runoff Model (GERM) to include permafrost and rock glaciers in Alpine catchments is presented here, and compared to the established one dimensional (1D) physics-based model SNOWPACK. The new permafrost component introduced to GERM treats permafrost as discreet depth layers in a 1D column for all grid cells, which have bulk thermal properties calculated from their constituents (ice, water, air, and solid component). The temperature evolution is computed using heat conduction and latent heat exchanges, modified by ventilation effects. Finally, we infer water runoff from permafrost degradation. Ground temperature variations calculated by both models are compared to borehole measurements at three Alpine sites and similar performances are found. Differences between the models are present in the amplitude of seasonal ground temperature variations, with SNOWPACK having a tendency to slightly overestimate them, while GERM underestimates them.

Gemäss verschiedenen Abschätzungen wird sich durch die Klimaveränderung nicht nur die Disposition für alpine Massenbewegungen, sondern auch deren Dynamik und die Interaktion von gravitativen Prozessen bzw. deren Verkettung in Prozesskaskaden verändern. Dies wird zu einem veränderten Risiko für die Schweizer Bevölkerung in Bezug auf alpine Massenbewegungen führen.
Das WSL Forschungsprogramm CCAMM - Climate Change Impacts on Alpine Mass Movements untersucht die Auswirkungen des Klimawandels auf alpine Massenbewegungen, um die daraus resultierenden Risiken besser abzuschätzen und geeignete Anpassungsstrategien für die Gesellschaft zu entwickeln. Im Folgenden stellen wir das WSL-Forschungsprogramm CCAMM vor.

Selon diverses estimations, le changement climatique modifiera non seulement la disposition des mouvements de masse alpins, mais aussi leur dynamique et l'interaction des processus gravitationnels ou leur enchaînement en cascade. Cela entraînera un changement de risque pour la population suisse par rapport aux mouvements de masse alpins.
Le programme de recherche du WSL CCAMM - Climate Change Impacts on Alpine Mass Movements - étudie les effets du changement climatique sur les mouvements de masse alpins afin de mieux évaluer les risques résultants et de développer des stratégies d'adaptation appropriées pour la société. Nous présentons ci-après le programme de recherche du WSL CCAMM.

Alpine permafrost is currently warming, leading to changes such as active layer deepening and talik formation. Frequency domain electro-magnetometry (FDEM) measurements were tested as a simple and efficient method to investigate ground characteristics along two transects on the ice-rich Schafberg rock glacier in the Eastern Swiss Alps. The results were compared with electrical resistivity tomography (ERT) and ground temperature data acquired simultaneously in boreholes. FDEM provides information on the electrical properties of the ground, allowing to investigate ground-ice distribution. Our device allowed measurements to a depth of around 7 m. In ice-rich permafrost, FDEM can provide an approximation of the active layer thickness, and ice-free zones within the permafrost such as intra-permafrost taliks can be identified. This rapidly applicable geophysical method can be used to monitor ground ice distribution easily and efficiently, making it an ideal complement to borehole temperature data, which only provide point information and are costly to install and maintain. At the Schafberg site the three methods FDEM, electrical resistivity tomography and borehole temperature measurements provided similar results, with regard to active layer thickness and the presence of unfrozen zones within the ice-rich permafrost.

An increasing number of studies highlight the controlling influence of water on rock glacier deformation velocities. The link between the concept of water‐driven shearing processes and numerous observations of correlating mean annual air or ground temperatures and rock glacier velocities is discussed here. We present a dataset measured at the Schafberg rock glacier in the Eastern Swiss Alps, complemented by temperature data from three other rock glaciers in the Swiss Alps, which allowed us to reconstruct the processes influencing both mean annual ground temperatures and rock glacier deformation velocity. Rock glacier hydrology is the parameter linking rock glacier temperature and velocities and is a crucial influencing factor. The main external forcing parameter appart from mean annual air temperature is early winter snow coverage. The study shows that the concept of water being a controlling factor for rock glacier velocity is no contradiction to the observed correlations between air or ground temperature and rock glacier deformation.