Samuel Morin

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• HDR, PhD
• Head at Centre National de Recherches Météorologiques, French National Centre for Scientific Research

Large snow load events are a major hazard for both human societies, in particular buildings and transport safety, and natural ecosystems. National and European frameworks provide guidelines and standards in order to take into account extreme snow load hazard in infrastructure design. However, there is a lack of reference data for their implementati...

Cet article synthétise l'évolution de l'enneigement dans les massifs montagneux français et ses conséquences pour les stations de sports d'hiver, dans le cadre de la trajectoire de réchauffement de référence pour l'adaptation au changement climatique (Tracc), qui considère des niveaux de réchauffement national de +2,7 °C et de +4 °C, depuis la péri...

Mountain areas crown their surrounding landscapes and host a great diversity of ecosystems and human activities. Due to their high altitudes and low temperatures, mountains, in many regions of the world, including Europe, allow the existence of the solid phase of water, ice, seasonally or perennially, which is found in glaciers, snow cover and perm...

Snow cover modeling remains a major challenge in climate and numerical weather prediction (NWP) models even in recent versions of high-resolution coupled surface–atmosphere (i.e., at kilometer scale) regional models. Evaluation of recent climate simulations, carried out as part of the WCRP-CORDEX Flagship Pilot Study on Convection (FPSCONV) with th...

Algae populate multiple habitats, including snow and ice, where they can form red blooms. These decrease snow albedo, accelerating snowmelt and potentially feeding back on snow and glacier decline caused by climate change. Quantifying this feedback requires the understanding of bloom evolution with climate change. Little, however, is known about th...

Snow cover modeling remains a major challenge in climate and numerical weather prediction (NWP) models, even in recent versions of high-resolution coupled surface-atmosphere (i.e. at km-scale) regional models. Evaluation of recent climate simulations, carried out as part of WCRP-CORDEX Flagship Pilot Study on Convection with the CNRM-AROME convecti...

The presence of a ski resort modifies the snow cover at the local scale, due to snow management practices on ski pistes, especially grooming and snowmaking. Snow management exerts 2-fold effects on the local hydrological cycle, through (i) abstraction and transfer of water used for snowmaking, and (ii) changes in water runoff due to added snow mass...

Following the projected increase in extreme precipitation, an increase in extreme snowfall may be expected in cold regions, e.g., for high latitudes or at high elevations. By contrast, in low- to medium-elevation areas, the probability of experiencing rainfall instead of snowfall is generally projected to increase due to warming conditions. Yet, in...

Assessing past distributions, variability and trends in the mountain snow cover and its first-order drivers, temperature and precipitation, is key for a wide range of studies and applications. In this study, we compare the results of various modeling systems (global and regional reanalyses ERA5, ERA5-Land, ERA5-Crocus, CERRA-Land, UERRA MESCAN-SURF...

Ski tourism is a substantial component of the economy of mountainous regions in Europe and is highly vulnerable to snow scarcity, which is increasing due to climate change. However, the climate change snow supply risk to ski tourism has not been quantified in a consistent way throughout Europe, including the influence and environmental footprint of...

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 t...

Nos simulations numériques du glacier de Saint-Sorlin (massif des Grandes Rousses) indiquent que ce glacier devrait disparaître vers 2050, quels que soient les scénarios climatiques envisagés. La comparaison de ces résultats avec les projections réalisées dans des études précédentes il y a une quinzaine d'années montre que l'évolution est beaucoup...

Following the projected increase in extreme precipitation, an increase in extreme snowfall may be expected in cold regions, e.g. for high latitudes or at high elevations. By contrast, in low/medium elevation areas, the probability to experience rainfall instead of snowfall is generally projected to increase due to warming conditions. In mountainous...

Assessing past distributions, variability and trends of the mountain snow cover and its first order drivers, temperature and precipitation, is key for a wide range of studies and applications. In this study, we compare the results of various modelling systems (global and regional reanalyses ERA5, ERA5-Land, ERA5-Crocus, CERRA-Land, UERRA MESCAN-SUR...

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...

This work proposes a holistic quantitative snow avalanche risk assessment that evaluates, at reasonable computational costs and for various types of buildings, the impact of forest cover changes on the probability distribution of runout distances, impact pressures and subsequent risk estimates. A typical case study of the French Alps shows that, fr...

Many mountainous regions in Europe, including their tourism sectors, show a high degree of economic specialization. The ski tourism industry forms part of the long-standing economic success of the French Alps. Over the past 20 years, snowmaking has become a key feature of ski tourism, but future climate change will decrease its effectiveness as an...

The presence of a ski resort modifies the snow cover at the local scale, due to snow management practices on ski slopes, especially grooming and snowmaking, which affect the quantity and physical behavior of the snowpack. Snow management exerts two-fold disturbances to the local hydrological cycle, through (i) uptake of water used for snowmaking, e...

Satellite remote sensing provides real time information on the extent of the snow cover. However, the period of record is generally too short to build a climatology from these data, preventing their use as climatic indicator. Here we show that reanalysis data can be used to reconstruct a 30-year snow cover time series that fits well the satellite o...

By darkening the snow surface, mineral dust and black carbon (BC) deposition enhances snowmelt and triggers numerous feedbacks. Assessments of their long-term impact at the regional scale are still largely missing despite the environmental and socio-economic implications of snow cover changes. Here we show, using numerical simulations, that dust an...

The specificities of mountain tourism areas and regional public policies influence the snowmaking equipment trajectories of ski resorts in the French Alps. Based on interviews among 20 ski resorts in Savoie (Northern French Alps) and data from regional policy of subsidies for snowmaking investments, this work analyses the drivers affecting the path...

Les spécificités des territoires touristiques de montagne et les politiques publiques régionales orientent les trajectoires d’équipement en production de neige des stations de ski des Alpes françaises. Sur la base d’entretiens auprès de 20 stations de ski de Savoie et de données de la politique régionale de subventionnement pour l’investissement da...

Anticipating risks related to climate extremes often relies on the quantification of large return levels (values exceeded with small probability) from climate projection ensembles. Current approaches based on multi-model ensembles (MMEs) usually estimate return levels separately for each climate simulation of the MME. In contrast, using MME obtaine...

Summer mountain pastures (also called alpages ) are a central element for many agro-pastoral livestock systems in the alpine region, by providing the feedstock for herds during the summer transhumance. However, vegetation phenology and productivity in mountain pastures are increasingly affected by climate hazards exacerbated by climate change, such...

A comprehensive assessment of twenty-first century climate change in the European Alps is presented. The analysis is based on the EURO-CORDEX regional climate model ensemble available at two grid spacings (12.5 and 50 km) and for three different greenhouse gas emission scenarios (RCPs 2.6, 4.5 and 8.5). The core simulation ensemble has been subject...

Les régions de montagne concentrent des caractéristiques qui rendent les effets du changement climatique particulièrement visibles. Elles constituent ainsi des sentinelles du changement en cours et à venir. Elles disposent d’atouts naturels et socio-économiques qui les distinguent d’autres zones géographiques, notamment sur le plan des ressources e...

Convection‐permitting climate modelling is a promising avenue for climate change research and services especially in mountainous regions. Work is required to evaluate the results of high‐resolution simulations against relevant observations, and put them in a broader context against coarser resolution modelling frameworks. Here we evaluate numerical...

This work introduces the S2M (SAFRAN–SURFEX/ISBA–Crocus–MEPRA) meteorological and snow cover reanalysis in the French Alps, Pyrenees and Corsica, spanning the time period from 1958 to 2021. The simulations are made over elementary areas, referred to as massifs, designed to represent the main drivers of the spatial variability observed in mountain r...

Snow reliability is a key climatic impact driver for the ski tourism industry, although there are only a few studies addressing past changes in snow reliability in ski resorts accounting for snow management practices (grooming and snowmaking, in particular). This study provides an assessment of past changes in natural and managed snow cover reliabi...

Mountains are highly significant regions in the context of climate change and sustainable development, at the intersection of accelerated warming and a large population depending directly or indirectly on them. They are regions of high biological and cultural diversity and provide vital goods and services to people living in and around mountain reg...

Avalanche risk changes through time due to climate, landscape and socio-environmental transformations. These drivers exhibit space-time variations as function of local peculiarities that may alter local avalanche risk trajectories. Here, we use an integrative methodology to track the co-evolution of the socio-economic, land cover and climatic drive...

Strategies for adapting to climate change are crucial to sustain human development while ensuring the supply of ecosystem services, especially in mid-altitude mountains. This paper presents main methodological developments and results of an inter- and transdisciplinary research that was applied to the Vercors massif in southeastern France. The appr...

Changes in snow cover associated with the warming of the French Alps greatly influence social-ecological systems through their impact on water resources, mountain ecosystems, economic activities, and glacier mass balance. In this study, we investigated trends in snow cover and temperature over the twentieth century using climate model and reanalysi...

Snow cover models support avalanche forecasting. However, despite much development to derive snow instability from snow cover model output, snow cover models presently do not provide information on avalanche problem types – an essential element to describe avalanche danger. We present an approach to detect, track and assess weak layers in snow cove...

Significance Snow avalanches represent a major threat in mountain environments, where they cause damage to critical infrastructure and claim hundreds of lives every year. Here, we document an unambiguous upslope migration of snow avalanches with climate change, a physical mechanism whose existence could previously not be demonstrated. In the Vosges...

The High Resolution Snow & Ice Monitoring Service was launched in 2020 to provide near-real-time, pan-European snow and ice information at 20 m resolution from Sentinel-2 observations. Here we present an evaluation of the snow detection using a database of snow depth observations from 1764 stations across Europe over the hydrological year 2016–2017...

Anticipating risks related to climate extremes often relies on the quantification of large return levels (values exceeded with small probability) from climate projection ensembles. Current approaches based on multi-model ensembles (MMEs) usually estimate return levels separately for each chain of the MME. By contrast, using MME obtained with differ...

Accurate snowfall measurements are necessary for meteorology, hydrology, and climate research. Typical uses include creating and calibrating gridded precipitation products, the verification of model simulations, driving hydrologic models, input into aircraft deicing processes, and estimating streamflow runoff in the spring. These applications are s...

Climate change projections indicate that extreme snowfall is expected to increase in cold areas, i.e., at high latitudes and/or high elevation, and to decrease in warmer areas, i.e., at mid-latitudes and low elevation. However, the magnitude of these contrasting patterns of change and their precise relations to elevation at the scale of a given mou...

This work introduces the S2M (SAFRAN - SURFEX/ISBA-Crocus - MEPRA) meteorological and snow cover reanalysis in the French Alps, Pyrenees and Corsica, spanning the time period from 1958 to 2020. The simulations are made over elementary areas, referred to as massifs, designed to represent the main drivers of the spatial variability observed in mounta...

Snow reliability is a key climatic impact driver for the ski tourism industry, for which there is more literature regarding future projections than past observed impacts. This study provides an assessment of past changes in natural and managed snow cover reliability from 1961 to 2018 in the French Alps. In particular, we used snowmaking investment...

The evaluation of snowpack models capable of accounting for snow management in ski resorts is a major step towards acceptance of such models in supporting the daily decision-making process of snow production managers. In the framework of the EU Horizon 2020 (H2020) project PROSNOW, a service to enable real-time optimization of grooming and snow-mak...

By darkening the snow surface, mineral dust and black carbon (BC) deposition enhances snowmelt and triggers numerous feedbacks. Assessments of their long-term impact at the regional scale are still largely missing despite the environmental and socio-economic implications of snow cover changes. Here we show, using numerical simulations, that dust an...

In the European Alps, air temperature has increased almost twice as much as the global average over the last century and, as a corollary, snow cover duration has decreased substantially. In the Arctic, dendroecological studies have evidenced that shrub growth is highly sensitive to temperature – this phenomenon has often been linked to shrub expans...

Remarkable episodes of avalanche events, so-called snow avalanche cycles, are recurring threats to people and infrastructures in mountainous areas. This study focuses on the hazard assessment of snow avalanche cycles defined by daily occurrence numbers exceeding the 2-year return level. To this aim, extreme value distributions are tailored to accou...

The High Resolution Snow & Ice Monitoring Service was launched in 2020 to provide near real time, pan-European snow and ice information at 20 m resolution from Sentinel-2 observations. Here we present an evaluation of the snow detection using a database of snow depth observations from 1764 stations across Europe over the hydrological year 2016–2017...

The modular Snow Microwave Radiative Transfer (SMRT) model simulates microwave scattering behavior in snow via different selectable theories and snow microstructure representations, which is well suited to intercomparisons analyses. Here, five microstructure models were parameterized from X-ray tomography and thin-section images of snow samples and...

Ski tourism plays a major socio-economic role in the snowy and mountainous areas of Europe such as the Alps, the Pyrenees, Nordic Europe, Eastern Europe, Anatolia, etc. Past and future climate change has an impact on the operating conditions of ski resorts, due to their reliance on natural snowfall and favorable conditions for snowmaking. However,...

Whilst there has been significant effort to stimulate the supply side of the market for climate services, the demand side still receives less attention. For this reason, this paper presents empirical data on prospective demand for (sub-)seasonal climate services addressing daily operational decision-making in ski resorts, particularly in the field...

The European Alps stretch over a range of climate zones which affect the spatial distribution of snow. Previous analyses of station observations of snow were confined to regional analyses. Here, we present an Alpine-wide analysis of snow depth from six Alpine countries – Austria, France, Germany, Italy, Slovenia, and Switzerland – including altoget...

Climate change projections indicate that extreme snowfall are expected to increase in cold areas, i.e. at high latitude and/or high elevation, and to decrease in warmer areas, i.e. at mid-latitude and low elevation. However, the magnitude of these contrasted patterns of change and their precise relations to elevation at the scale of a given mountai...

Determining avalanche activity corresponding to given snow and meteorological conditions is an old problem of high practical relevance. To address it, numerous statistical forecasting models have been developed, but intercomparisons of their efficiency on very large datasets are seldom. In this work, an approach combining random forests with class-...

The evaluation of snowpack models capable of accounting for snow management in ski resorts is a major step towards acceptance of such models in supporting the daily decision-making process of snow production managers. In the frame of the EU H2020 project PROSNOW, a service to enable real-time optimisation of grooming and snow-making in ski resorts...

The Mountain Research Initiative (MRI) promotes basic and applied research to understand how drivers and processes of global change present challenges and opportunities in mountain social-ecological systems. It convenes a global network that collectively generates and synthesizes knowledge on global change in mountains that also supports decisions...

Changes in precipitation over the European Alps are investigated with the regional climate model MAR (Modèle Atmosphérique Régional) applied with a 7 km resolution over the period 1903–2010 using the reanalysis ERA-20C as forcing. A comparison with several observational datasets demonstrates that the model is able to reproduce the climatology as we...

In a context of climate change, trends in extreme snow loads need to be determined to minimize the risk of structure collapse. We study trends in 50-year return levels of ground snow load (GSL) using non-stationary extreme value models. These trends are assessed at a mountain massif scale from GSL data, provided for the French Alps from 1959 to 201...

The European Alps stretch over a range of climate zones, which affect the spatial distribution of snow. Previous analyses of station observations of snow were confined to regional analyses. Here, we present an Alpine wide analysis of snow depth from six Alpine countries: Austria, France, Germany, Italy, Slovenia, and Switzerland; including altogeth...

The snow cover is a key component of land surface hydrology, especially in mountain areas where it governs the amount and timing of water availability in downstream areas. It is involved in relevant climate feedbacks and natural hazards such as avalanches and floods. Monitoring and forecasting snow cover characteristics is challenging. While snow c...

Changes in mountain landscape can affect avalanche activity, causing changes in risk, potentially enhanced by a transition of the socio-environmental system and its underlying dynamics. Thus, integrative approaches combining biophysical and social sciences are required to assess changes in risk in all its dimensions. This study proposes a holistic...

This study investigates the relationship between snow conditions and snowmaking investments for over 100 French Alps ski resorts. Investment trends represent a critical issue in capital-intensive sectors such as the ski industry. The data are based on snow reliability indicators and snowmaking investments covering 1997–2014. Descriptive statistics...

This study investigated the temporal variability and changes in snow cover duration and the average snow depth from December to April in the Pyrenees at 1,500 and 2,100 m a.s.l. for the period 1958–2017. This is the first such analysis for the entire mountain range using SAFRAN‐Crocus simulations run for this specific purpose. The SAFRAN‐Crocus sim...

This study presents the evolution of the snow reliability in the 24 alpine ski resorts of the Isère département (Northern French Alps, around Grenoble) over the last decades and its projection into the 21st century, taking into account grooming and snowmaking. The water demand for snowmaking is calculated and can be compared with hydrological simul...

Cette étude présente l’évolution de la fiabilité de l’enneigement des 24 domaines de ski alpin du département de l’Isère sur les dernières années et sa projection au XXIe siècle en prenant en compte le damage et la neige de culture. La demande en eau pour sécuriser l’enneigement est ainsi calculée et peut être comparée aux modélisations de disponib...

Snow management, i. e., snowmaking and grooming, is an integral part of modern ski resort management. While the current snow cover distribution on the slopes is often well known thanks to the usage of advanced monitoring techniques, information about its future evolution is usually lacking. Management-enabled numerical snowpack models driven by met...

Abstract. In a context of climate change, trends in extreme snow loads need to be determined to minimize the risk of structure collapse.We study trends in annual maxima of ground snow load (GSL) using non-stationary extreme value models. Trends in return levels of GSL are assessed at a mountain massif scale from GSL data, provided for the French Al...

Indicators are widely used in climate variability and climate change assessments to simplify the tracking of complex processes and phenomena in the state of the environment. Apart from the climatic criteria, the snow indicators in ski tourism have been increasingly extended with elements that relate to the technical, operational, and commercial asp...

Changes of precipitation over the European Alps are investigated with the regional climate model MAR applied with a 7-km resolution over the period 1903–2010 using the reanalysis ERA-20C as forcing. A comparison with several observational datasets demonstrates that the model is able to reproduce the climatology as well as both the inter-annual vari...

À travers les paysages splendides des montagnes suisses, autrichiennes, françaises et allemandes, ce documentaire accompagne tout au long d’une saison hivernale des sauveteurs, des scientifiques et des chercheurs qui se consacrent aux sommets glacés et à leurs dangers.

La gestion des risques dans les régions montagneuses nécessite une caractérisation des extrêmes neigeux. Nous utilisons le cadre des processus max-stables, qui relient statistique des valeurs extrêmes et géostatistique, pour étudier la dépendance spatiale des maxima hivernaux de chutes de neige cumulées sur 3 jours et de hauteurs de neige dans les...