Slope stability problems related to glacier shrinkage and permafrost degradation in the Alps

Haeberli, Wilfried; Wegmann, Matthias; Mühll, Daniel Vonder

doi:10.5169/seals-168172

Cited by 27 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the spatial distribution of alpine permafrost (Boeckli and others, 2012; Magnin and others, 2015 a ) and cold-based glaciers (Suter and Hoelzle, 2002; Haeberli and others, 2004) which are frozen to bedrock (Waller, 2001; Faillettaz and others, 2011), IAs are interpreted as permafrost evidence (Haeberli and others, 1997; Gruber and Haeberli, 2007), and it has been assumed that IAs are composed of cold ice (Haeberli, 1975; Guillet and others, 2021). This thermal state had to be confirmed through recent systematic in situ temperature measurements in boreholes.…”

Section: Ice Aprons: Cold Ice Bodiesmentioning

confidence: 99%

Ice aprons on steep high-alpine slopes: insights from the Mont-Blanc massif, Western Alps

et al. 2023

View full text Add to dashboard Cite

Ice aprons are defined as very small ice bodies covering steep rock slopes. They have only been the subject of increased scientific interest for a few years, despite the fact that they are a condition for mountaineering and obvious elements in the high-alpine landscapes. However, very little is known about their distribution, evolution and physical characteristics. In this paper, we review the existing knowledge on ice aprons, which have almost exclusively been investigated in the Mont-Blanc massif, Western Alps. We supplement this review with novel results from recent surveys of ice aprons. We used a wide array of methodologies, from remote sensing (multi-source imagery) to in situ (stakes and thermal monitoring) and laboratory (radiocarbon dating and texture analysis) glaciological investigations. In the Mont-Blanc massif, ice aprons occupy 4.2 km2 within the alpine permafrost zone. Temperature measured at the ice–rock interface is indeed largely negative. Thinness of ice aprons coupled with the cold context implies a quasi-stationary shear regime without basal Sliding. Only ice at the surface can possibly melt in warm periods. After a shrinking period from the end of the Little Ice Age to the mid-to-late-1960s, ice aprons experienced a short period of expansion, followed by an accelerated shrinkage since the beginning of the 21st century. This shrinkage now favours rockfall triggering and poses a serious threat to a glaciological heritage since ice aprons host several-thousand-year-old ice. Finally, we synthesize this information to assess the existing definition of ice aprons, and propose some future research directions.

show abstract

Section: Ice Aprons: Cold Ice Bodiesmentioning

confidence: 99%

Ice aprons on steep high-alpine slopes: insights from the Mont-Blanc massif, Western Alps

et al. 2023

View full text Add to dashboard Cite

show abstract

“…The potential destabilizing effects of mountain surfaces under cryospheric change are well known globally (Gądek, 2014;Haeberli et al, 1997;Haeberli & Beniston, 1998;Harrison, 2009;Knight & Harrison, 2014;Krautblatter et al, 2012) and have been examined…”

Section: Hazard Responses To the Changing Mountain Cryospherementioning

confidence: 99%

The sensitivity and evolutionary trajectory of the mountain cryosphere: Implications for mountain geomorphic systems and hazards

Knight

Harrison

2023

Land Degrad Dev

View full text Add to dashboard Cite

Global climate change gives rise to changing spatial patterns of snow and ice, especially over mountain blocks where orographic and synoptic circulation effects play significant roles in creating patterns of precipitation and glacier development. The presence of snow and ice results in heat balance changes and other land surface feedbacks that have implications for patterns of mountain glacier retreat and the dynamics of mountain geomorphic systems. This study considers the sensitivity of the mountain cryosphere (snow, ice, permafrost) to global climate change, and the implications of this sensitivity analysis for evaluating mountain surface stability, geomorphic change, and the generation of mountain geohazards. Consideration of these issues is informed by evidence from case studies reported in the literature and by field observations of mountain system dynamics worldwide. Results show that ‘sensitivity’ to climate forcing has been interpreted and defined in different ways in mountain snow, ice, and permafrost systems, with respect to properties such as albedo, mass balance or rapidity of system change. There are also significant spatial differences in sensitivity between different mountain blocks for snow, ice and permafrost, and these regions are therefore likely to follow different trajectories of geomorphic change in response to climate forcing, related to their physiographic properties and the extent of cryospheric coverage. Within glaciated mountains in particular, the relative timing of different geomorphic events, and the interplay between slope, glacier front, and proglacial sediment sources and environments, may vary depending on glacier size, geomorphic setting, and microclimate. By contrast, responses to permafrost warming (increased surface instability and mass movements) and changes in snow patterns (avalanche risk, floods) may have quite different spatial and temporal patterns and influenced by different environmental controls. An integrated evolutionary model for mountain system development under a changing cryosphere is proposed, highlighting the critical role of energy balance as a forcing factor that then triggers downstream mountain system responses. This suggests that different elements of mountain systems exhibit different sensitivities, and furthermore that these sensitivities change over time and space through the period of anthropogenic global warming and paraglacial relaxation.

show abstract

Temporal evolution of headwall erosion rates derived from cosmogenic nuclide concentrations in the medial moraines of Glacier d'Otemma, Switzerland

Wetterauer

Scherler

Anderson

et al. 2022

Earth Surf Processes Landf

View full text Add to dashboard Cite

Climate change affects the stability and erosion of high‐alpine rock walls above glaciers (headwalls) that deliver debris to glacier surfaces. Since supraglacial debris in the ablation zone alters the melt behaviour of the underlying ice, the responses of debris‐covered glaciers and of headwalls to climate change may be coupled. In this study, we analyse the beryllium‐10 (10Be)‐cosmogenic nuclide concentration history of glacial headwalls delivering debris to the Glacier d'Otemma in Switzerland. By systematic downglacier‐profile‐sampling of two parallel medial moraines, we assess changes in headwall erosion through time for small, well‐defined debris source areas. We compute apparent headwall erosion rates from 10Be concentrations ([10Be]), measured in 15 amalgamated medial moraine debris samples. To estimate both the additional 10Be production during glacial debris transport and the age of our samples we combine our field‐based data with a simple model that simulates downglacier debris trajectories. Furthermore, we evaluate additional grain size fractions for eight samples to test for stochastic mass wasting effects on [10Be]. Our results indicate that [10Be] along the medial moraines vary systematically with time and consistently for different grain sizes. [10Be] are higher for older debris, closer to the glacier terminus, and lower for younger debris, closer to the glacier head. Computed apparent headwall erosion rates vary between ~0.6 and 10.8 mm yr−1, increasing over a maximum time span of ~200 years towards the present. As ice cover retreats, newly exposed headwall surfaces may become susceptible to enhanced weathering and erosion, expand to lower elevations, and contribute formerly shielded bedrock of likely different [10Be]. Hence, we suggest that recently lower [10Be] reflect the deglaciation of the debris source areas since the end of the Little Ice Age.

show abstract

Slope stability problems related to glacier shrinkage and permafrost degradation in the Alps

Cited by 27 publications

References 0 publications

Ice aprons on steep high-alpine slopes: insights from the Mont-Blanc massif, Western Alps

Ice aprons on steep high-alpine slopes: insights from the Mont-Blanc massif, Western Alps

The sensitivity and evolutionary trajectory of the mountain cryosphere: Implications for mountain geomorphic systems and hazards

Temporal evolution of headwall erosion rates derived from cosmogenic nuclide concentrations in the medial moraines of Glacier d'Otemma, Switzerland

Contact Info

Product

Resources

About