Emmanuel Thibert

French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Department of Waters

Particle size, particle speed and airflow speed have been measured in the powder snow clouds of avalanches to investigate the suspension and transportation processes of snow particles. The avalanches were artificially triggered at the Lautaret full-scale avalanche test-site (French Alps) where an ultrasonic anemometer and a snow particle counter (S...

Saharan dust outbreaks have profound effects on ecosystems, climate, human health and the cryosphere in Europe. However, the spatial deposition pattern of Saharan dust is poorly known due to a sparse network of ground measurements. Following the extreme dust deposition event of February 2021 across Europe, a citizen science campaign was launched to...

Temperature-index models have been widely used for glacier-mass projections over the 21st century. The ability of temperature-index models to capture nonlinear responses of glacier mass balance (MB) to high deviations in air temperature and solid precipitation has recently been questioned by mass-balance simulations employing advanced machine-learn...

The cover image is based on the Research Article Changes in surface velocities over four decades on the Laurichard rock glacier (French Alps) by Emmanuel Thibert and Xavier Bodin, https://doi.org/10.1002/ppp.2159. Image Credit: B. Nicollet©Parc Natioan des Ecrins.

The hydromechanical processes by which basal water controls sliding at the glacier bed are poorly known, despite glacier basal motion being responsible for a large part of ice flux in temperate alpine glaciers. Previous studies suggest that sliding strongly relates to the quantity of water being stored at the ice‐bedrock interface. However, this wa...

The longest time series of surface velocities recorded on a rock glacier in the French Alps, covering more than three decades, has been recorded since 1983 on the Laurichard rock glacier (Ecrins range). The time signal of velocity changes is extracted from variance analyses separating time and space variabilities on the rock glacier surface to prov...

Rock glaciers are creeping bodies of ice and rock that account for an important part of the mountain cryosphere. In this study, we investigated long‐term changes of the Laurichard rock glacier (French Alps), to understand how this rock glacier is responding to climate change. Using feature‐tracking and photogrammetric measurements between 1952 and...

Mass balance observations are very useful to assess climate change in different regions of the world. As opposed to glacier-wide mass balances which are influenced by the dynamic response of each glacier, point mass balances provide a direct climatic signal that depends on surface accumulation and ablation only. Unfortunately, major efforts are req...

In mountain areas, rock glaciers are markers of climate change. Besides temperature effect, their surface flow velocity can be influenced by ice proportion and other mechanical and physical properties. To improve the understanding of the processes influencing thermal control and the seasonal and inter-annual variations, this study on the Laurichard...

Mass balance observations are very useful to assess climate change in different regions of the world. As opposed to glacier-wide mass balances, which are influenced by the dynamic response of each glacier, point mass-balances provide a direct climatic signal that depends on surface accumulation and ablation only. Unfortunately, major efforts are re...

Comprehensive assessments of global glacier mass changes based on a variety of observations and prevailing methodologies have been published at multi-annual intervals. For the years in between, the glaciological method provides annual observations of specific mass changes but is suspected to not be representative at the regional to global scales du...

Physically-based avalanche propagation models must still be locally calibrated to provide robust predictions, e.g. in long-term forecasting and subsequent risk assessment. Friction parameters cannot be measured directly and need to be estimated from observations. Rich and diverse data are now increasingly available from test-sites, but for measurem...

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Comprehensive assessments of global glacier mass changes based on a variety of observations and prevailing methodologies have been published at multi-annual intervals. For the years in between, the glaciological method provides annual observations of specific mass changes but is suspected to not be representative at the regional to global scales du...

Capturing the spatial and temporal variability of precipitation at fine scale is necessary for high-resolution modeling of snowpack and glacier mass balance in alpine terrain. In this study, we assess the impact of three sub-kilometer precipitation datasets on distributed simulations of snowpack and glacier mass balance with the detailed snowpack m...

The Taconnaz avalanche protection system combines several structures, including large and small retarding mounds and a 25-m-high catching dam, whose aims is to dissipate the energy of large snow avalanches, deflect them and shorten their run-out distance. A large part of the protection system was recently rebuilt and/or improved in order to face th...

The largest collection so far of glaciological and geodetic observations suggests that glaciers contributed about 27 millimetres to sea-level rise from 1961 to 2016, at rates of ice loss that could see the disappearance of many glaciers this century.

The French critical zone initiative, called OZCAR (Observatoires de la Zone Critique–Application et Recherche or Critical Zone Observatories–Application and Research) is a National Research Infrastructure (RI). OZCAR-RI is a network of instrumented sites, bringing together 21 pre-existing research observatories monitoring different compartments of...

This book presents the impact of climate change related to many environmental, economic and social issues in southern Alps.

The present paper describes preliminary re-analyses of field-based data on past well-documented snow avalanches that have impacted an instrumented tripod structure in one of the paths at Lautaret avalanche test-site, France. The re-analyses done include data on velocity and pressure measurements , as well as new data on flow-depth measurements. The...

High-elevation glaciers are undergoing substantial warming in response to current climate change. This warming is affecting the ice/rock interface temperature, the primary control of glacier stability on steep slopes. Instability may give rise to the collapse of large parts of hanging glaciers. The rheology of ice-avalanches is still poorly known b...

Understanding changes in glacier mass balances is essential for investigating climate changes. However, glacier-wide mass balances determined from geodetic observations do not provide a relevant climatic signal as they depend on the dynamic response of the glaciers. In situ point mass balance measurements provide a direct signal but show a strong s...

The Laurichard active rock glacier is the permafrost-related landform with the longest record of surface velocity in France from 1984 up to 2017 providing a spatial-temporal dataset of annual rocks displacements (13 velocity point-measurements x 26 years). The time signal from such data set is expected to be related to year-to-year changes in clima...

The monitoring of surface flow velocities at active rock glaciers has a long tradition in the European Alps with first surveys in the 1920s. Since the 1990s annual to seasonal flow velocity monitoring activities have been substantially expanded and partly institutionalized. In this article, we present and compare annual rock glacier surface flow ve...

Rock glaciers result from the long-term creeping of ice-rich permafrost along mountain slopes. Under warming conditions, deformation is expected to increase, and potential destabilization of those landforms may lead to hazardous phenomena. Monitoring the kinematics of rock glaciers at fine spatial resolution is required to better understand at whic...

Recent record-breaking glacier melt values are attributable to peculiar extreme events and long-term warming trends that shift averages upwards. Analyzing one of the world's longest mass-balance series with extreme value statistics, we show that detrending melt anomalies makes it possible to disentangle these effects, leading to a fairer evaluation...

Mass balance of glaciers are essential to study climate changes in different regions of the world. Previous studies showed that it is crucial to directly use the point mass balance observations to extract a consistent climatic signal rather than glacier-wide mass balances. However, for this purpose, accounting for the high spatio-temporal mass bala...

Cet article fait une analyse en retour brève de l'avalanche de neige de grande ampleur survenue le 9 janvier 2018 et qui a rempli en grande partie le paravalanche.

The production of Machine Made (MM) snow is now generalized in ski resorts and represents the most common method of adaptation for mitigating the impact of a lack of snow on skiing. Most investigations of correlations between snow conditions and the ski industry’s economy focus on the production of MM snow though not one of these has taken into acc...

Conventional glacier-wide mass balances are commonly used to study the effect of climate forcing on glacier melt. Unfortunately, the glacier-wide mass balances are also influenced by the glacier's dynamic response. Investigations on the effects of climate forcing on glaciers can be largely improved by analyzing point mass balances. Using a statisti...

Cet article traite du comportement de structures en Béton Armé (BA) sous l'effet de chargements d’avalanche de neige. L'approche pression-impulsion proposée permet de mettre en exergue trois types de comportement théoriques en fonction de l'impulsion du chargement. En pratique, si l'on confronte les diagrammes obtenus pour deux types de structure à...

Ce livret vient en complément du premier livret sur les idées reçues sur les risques naturels en montagne, paru en 2013. Il aborde la question des idées reçues sur le changement climatique en montagne, sur la base de connaissances acquises dans les projets de recherche du centre Irstea de Grenoble. Les risques en montagne vont-ils augmenter ou au c...

The production of Machine Made (MM) snow is now generalized in ski resorts and represents the most common adaptation method to mitigate the impacts of both the natural variability and projected changes of the climate on the snow conditions to guarantee suitable conditions for skiing. Most investigations of the impact of snow conditions on the econo...

The deformation of rock glaciers is a climate-dependent process which affects many mountain debris slopes underlain with ice-rich permafrost (Haeberli et al., 2006). Under temperate conditions, like in the Alps, the typical magnitude of movement is in the order of a few dm/a to 1-2 m/a (Barsch, 1996). However, recent measurements of accelerating ro...

Low-speed wet avalanches exert hydrostatic forces on structures that are flow-depth dependent. However, the pressure amplification experienced by smaller structures has not been quantified previously. In particular, recent wet avalanche pressure measurements, performed with small cells at the "Vallée de la Sionne" test site, indicate significantly...

In polythermal glaciers, specific climatic, topographic, and exposure conditions may lead to the formation of englacial lakes that can produce catastrophic effects downstream in the event of abrupt natural drainage.We have determined how a combination of ground-penetrating radar (GPR) and surface nuclear magnetic resonance (SNMR) surveys helped to...

In accordance with their mission and as part of their long-term observation work, Ecrins National Park (NP) is making important contributions to the study and monitoring of phenomena related to climate change. Its work takes information collected at different meteorological stations and supplements it with analyses of vegetation changes through aer...

Formation of intraglacial lakes in polythermal glaciers results from specific climatic, topographic and aspect conditions. Their occurrence constitutes a significant threat to the valleys located below in case of sudden discharge occurring without any warning prior signs. Such case occurred in 1892 at Saint-Gervais (French Alps), where a deadly wat...

The deadliest outburst flood from an englacial cavity occurred on Glacier de Tête Rousse in the Mont Blanc area, French Alps, in 1892. A subglacial reservoir was discovered in the same glacier in 2010 and drained artificially in 2010, 2011 and 2012 to protect the 3000 inhabitants downstream. The mechanism leading to the spontaneous refilling of the...

The supply of glacier water to La Paz city, Bolivia, between 1963 and 2006 was assessed at annual and seasonal timescales based on the mass-balance quantification of 70 glaciers located within the drainage basins of La Paz. Glaciers contributed about 15% of water resources at an annual scale (14% in the wet season, 27% in the dry season). Uncertain...

The full-scale avalanche test site at Lautaret Pass in the southern French Alps has been used by IRSTEA-Cemagref Research Institute since 1972. Over recent years, two avalanche paths have been used routinely to release avalanches and study avalanche dynamics and interactions between avalanches and obstacles. Avalanche flows are generally dense and...

Systematic snow disposal from street cleaning operations may create large anthropogenic snow/ice bodies. Such man-made cryospheric objects may be considered as complex geophysical interfaces between the atmosphere, landscape, soils and hydrosphere. Urban snow patches not only produce large amounts of meltwater (and therefore a risk of flooding), bu...

Very large volumes of ice break off regularly from Taconnaz hanging glacier, French Alps. During winter, when the snow mantle is unstable, these collapses can trigger very large avalanches that represent a serious threat to inhabited areas below. Photogrammetric measurements have been performed over 1 year to assess the volume and frequency of the...

We present Ground Penetrating radar and Surface Nuclear magnetic resonance investigations of an englacial water pocket embedded in the polythermal glacier of Tête Rousse. Besides glacier bed and crevasses characterization, these data allowed the monitoring of the cavity whose geometry changed after artificial water drainages were performed.

Dynamic avalanche modeling requires as input the volumes and areas of the snow released, and consequently the fracture heights. Determining these parameters requires high-resolution spatial snow surface data from before and after an avalanche. In snow and avalanche research, terrestrial laser scanners are used increasingly to efficiently and accura...

Under tropical conditions, water discharge from glaciers is crucial for water resources in the dry season, as it is the case for La Paz, Bolivia (16S). In the current study, the glacier water supply of La Paz city has been assessed at annual and seasonal time-scale for the first time thanks to the mass balance analysis of 70 glaciers located within...

Tête Rousse is a small polythermal glacier located in the Mont Blanc area (French Alps) at an altitude of 3100 to3300 m. In 1892, an outburst flood from this glacier released about 200 000m3 of water mixed with ice, causing much damage. A new accumulation of melt water in the glacier was not excluded. The uncertainty related to such glacier conditi...

ABTRACT : The Voellmy avalanche basal friction parameters are retrieved from high rate positioning of artificially released avalanches. Two dense snow avalanches were triggered at the Lautaret full-scale test site on December 19th 2012 and February 13th 2013. Their fronts were tracked thanks to an accurate photogrammetric system. Couples of images...