Impacts of land-cover changes on dendrogeomorphic reconstructions of snow avalanches: Insights from the Queyras massif (French Alps)

2020 ◽  
Author(s):  
Adrien Favillier ◽  
Robin Mainieri ◽  
Jérôme Lopez-Saez ◽  
Mélanie Saulnier ◽  
Nicolas Eckert ◽  
...  
Keyword(s):  
Global Warming ◽  
Snow Cover ◽  
Tree Ring ◽  
Environmental Changes ◽  
Mass Movement ◽  
Sudden Change ◽  
Snow Avalanche ◽  
High Mountain ◽  
Snow Avalanches ◽  
French Alps

<p>In the course of the 20th century, high-mountain regions, such as the Alps, have experienced a significant warming with temperature increase twice as much as the global average. Such warming strongly alters the cryosphere components. It induces, for example, a shift from solid to liquid precipitation, more frequent and more intense snowmelt phases or a strong decrease in the amount and duration of snow cover, especially at the location of the snow-rain transition. Such changes in snow cover characteristics are expected to induce changes in spontaneous avalanche activity.</p><p>On forested stands, dendrogeomorphic analyses provide long and continuous chronologies of snow avalanche events and can thus contribute to the detection of trends potentially related to climate change. However, the non-stationarities found in tree-ring based chronologies of snow avalanches may also be related to socio-environmental changes. In this context, based on the latest the latest developments in dendrogeomorphology, we reconstructed the snow avalanche activity for 6 contiguous paths located in the Grand Bois de Souliers slope (Queyras massif, French Alps) with the aim to :</p><ol><li>Detect and illustrate such confounding effects;</li> <li>Disentangle the trends inherent to tree-ring approaches from real fluctuations in avalanche activity.</li> </ol><p>The resulting reconstruction covers the period 1750-2016 and evidences two clearly different trends: on the three southern avalanche paths, a sharp increase in the frequency of reconstructed events is observed since the 1970s. The distribution of tree ages, in combination with old topographic maps, allows an attribution of this non-stationarity to the destruction of a large part of the forest stand in the 1910-20s, presumably related to a devastating avalanche event. This extreme event induced a sudden change in the capability of newly colonizing trees to yield dendrogeomorphic records as information on previous or subsequent events has been removed. By contrast, on the three northern paths, snow avalanche activity is truly characterized by a strong reduction since the 1930s related to the progressive afforestation of the paths since the mid-18<sup>th</sup> century and to the colonization of the release areas since World War 2. Even if we cannot rule out the possibility that global warming may have played a certain, yet likely minor, role in the evolution of these avalanche-forest ecosystem, we conclude that the contrasted evolutions observed between the avalanche paths can, above all, be explained by socio-environmental factors (e.g., forest and grazing management) during the 18<sup>th</sup> century that have gained in importance by the rural exodus and the abatement of pastoral practices during the 20<sup>th</sup> century. In that sense, our results evidence quite clearly the crucial need for future studies aimed at detecting changes in mass-movement activity from tree-ring analyses to systematically interpret trends in activity considering interrelations between forest evolution, global warming, social practices and process activity itself.</p>

scholarly journals Snow Avalanche Assessment in Mass Movement-Prone Areas: Results from Climate Extremization in Relationship with Environmental Risk Reduction in the Prati di Tivo Area (Gran Sasso Massif, Central Italy)

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1176
Author(s):  
Massimiliano Fazzini ◽  
Marco Cordeschi ◽  
Cristiano Carabella ◽  
Giorgio Paglia ◽  
Gianluca Esposito ◽  
...  
Keyword(s):  
Risk Mitigation ◽  
Mass Movement ◽  
Central Italy ◽  
Scientific Basis ◽  
Snow Avalanche ◽  
High Mountain ◽  
Mass Movements ◽  
Snow Avalanches ◽  
Massif Central ◽  
Mountain Environments

Mass movements processes (i.e., landslides and snow avalanches) play an important role in landscape evolution and largely affect high mountain environments worldwide and in Italy. The increase in temperatures, the irregularity of intense weather events, and several heavy snowfall events increased mass movements’ occurrence, especially in mountain regions with a high impact on settlements, infrastructures, and well-developed tourist facilities. In detail, the Prati di Tivo area, located on the northern slope of the Gran Sasso Massif (Central Italy), has been widely affected by mass movement phenomena. Following some recent damaging snow avalanches, a risk mitigation protocol has been activated to develop mitigation activities and land use policies. The main goal was to perform a multidisciplinary analysis of detailed climatic and geomorphological analysis, integrated with Geographic Information System (GIS) processing, to advance snow avalanche hazard assessment methodologies in mass movement-prone areas. Furthermore, this work could represent an operative tool for any geomorphological hazard studies in high mountainous environments, readily available to interested stakeholders. It could also provide a scientific basis for implementing sustainable territorial planning, emergency management, and loss-reduction measures.

scholarly journals A Reconstruction of Snow-Avalanche Characteristics in Montana, U.S.A., Using Vegetative Indicators

1985 ◽  
Vol 31 (108) ◽  
pp. 185-187 ◽  
Author(s):  
David R. Butler ◽  
George P. Malanson
Keyword(s):  
Tree Ring ◽  
National Park ◽  
Natural Hazard ◽  
Snow Avalanche ◽  
Glacier National Park ◽  
Snow Avalanches ◽  
Southern Boundary ◽  
Tree Ring Data ◽  
Wet Snow

AbstractWidespread wet-snow avalanches were observed on the southern boundary of Glacier National Park, Montana, in February 1979. Severe tilting, scarring, and breakage of trees were observed along a transverse trim-line of one path, 70 m from a wet-snow deposit. Tree-ring data were used to establish the date of occurrence, and the nature of damage was used to characterize the avalanche event. The event probably included a previously unrecognized dry-snow avalanche and associated wind blast. Such events present different problems for natural-hazard planning. The nature of vegetative damage along the margins of avalanche paths is shown to be a useful indicator of the characteristics of past unobserved avalanche events.

Reconstructing snow-avalanche activity with tree rings in Maramureş Mountains (Eastern Carpathians, Romania)

2020 ◽  
Author(s):  
Armelle Decaulne ◽  
Ionela-Georgiana Răchită ◽  
Mihai Hotea ◽  
Vasile Timur Chiş ◽  
Olimpiu Traian Pop
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Climatic Factors ◽  
Climatic Conditions ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Joint Research ◽  
Eastern Carpathians ◽  
Joint Research Project ◽  
Callus Tissues

<p> <span>Snow avalanches </span>represent a common phenomenon <span>in Maramureş Mountains (Eastern Carpathians, Romania)</span> where they <span>occur frequently on higher steep slopes and reach in the runout zones the valley bottoms below 1000 m a.s.l. The presence of particular topo-climatic conditions influences the patterns of avalanche activity in terms of past frequency and spatial extent along the slope valleys. As the past snow-avalanche activity is not documented by written reports in the area, reliable information about avalanche history is missing. </span>However, the slopes are forested, trees repeatedly disturbed by snow avalanches record evidence of past events. <span>For this study we reconstructed the avalanche activity using tree rings as a source of proxy data. To date the snow-avalanche history, dendrochronological investigations have been carried out in two avalanche paths, along which living trees showed clear external signs of past disturbances related to mechanical impacts produced by snow avalanches. In each investigated path, a total number of 52 and respectively 118 trees have been sampled and their spatial position recorded with a GPS device. Tree-growth </span>anomalies (e.g. scars, callus tissues, the onset sequences of tangential rows of traumatic resin ducts, compression wood, growth suppression and release sequences) <span>related to snow avalanche disturbance identified within tree rings served to reconstruct past events with an annual resolution. The results indicate that, apart the 2005 major event witnessed and also confirmed by tree-ring dating, multiple other events have been reconstructed since the beginning of 20</span><sup><span>th</span></sup><span> century. Despite some inherent limitations of tree-ring methods in reconstructing past avalanche events, these dendrochronological investigations confirm their utility in deciphering the patterns of avalanche activity in Maramureş Mountains. Tree-ring studies contribute to a better understanding of the role of topographical and climatic factors which influence the spatio-temporal occurrence of snow avalanches.</span></p><p><span>This study represents a contribution to the joint research project 09-AUF, </span><span>‘‘</span><span><em>Activité des avalanches de neige dans les Carpates Orientales Roumaines et Ukrainiennes - </em></span><span> ACTIVNEIGE</span><span>’’</span><span>, co-funded by the </span><span><em>Agence Universitaire de la Francophonie (AUF)</em></span><span> and </span><span><em>Institutul de Fizică Atomică (IFA), Romania</em></span><span>.</span></p>

scholarly journals Brief communication: Weak control of snow avalanche deposit volumes by paths morphological characteristics

2021 ◽  
Author(s):  
Hippolyte Kern ◽  
Nicolas Eckert ◽  
Vincent Jomelli ◽  
Delphine Grancher ◽  
Michael Deschatres ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Snow Avalanche ◽  
Statistical Techniques ◽  
Snow Avalanches ◽  
Climate Conditions ◽  
French Alps ◽  
Non Linear ◽  
Genesis Of Deposit ◽  
Mechanical Thresholds ◽  
Linear Nature

Abstract. Snow avalanches are a major component of the mountain cryosphere, but little is known about the factors controlling the variability of their deposit volumes. This study investigates the influence of morphological characteristics on c. 1500 deposit volumes recorded between 2003 and 2018 in 77 snow avalanche paths of the French Alps. Different statistical techniques show a slight but significant link between deposit volumes and path mean elevation and orientation, with contrasted patterns between winter and spring seasons. The weakness, partially non-linear nature of this control may result from the combined influence on the genesis of deposit volumes of mean path activity, climate conditions and mechanical thresholds determining avalanche release.

Tree-ring dating of snow avalanche history in Parâng Mountains (Southern Carpathians, Romania)

2020 ◽  
Author(s):  
Corina Todea ◽  
Olimpiu Pop
Keyword(s):  
Tree Ring ◽  
Snow Avalanche ◽  
Mountainous Area ◽  
Snow Avalanches ◽  
The Past ◽  
Avalanche Hazard ◽  
Hiking Trails ◽  
Traumatic Resin Ducts ◽  
Tree Ring Data ◽  
Southern Carpathians

<p>In high mountainous areas worldwide, snow avalanches represent one of the main morphodynamic processes which influence the morphology of steep slopes. They usually disturb the forests, and represent a significant natural hazard that may endanger the safety of tourists exposed along the hiking trails crossing the avalanche-prone slopes. In the context of the growing tourism activities in the area where tourist become exposed to snow avalanche hazard, there is need for detailed analysis for documenting the past activity of this geomorphic process, especially in remote areas where historical data is lacking. Such mountainous area without snow avalanche monitoring and archival records is in Parâng Mountains (Southern Carpathians, Romania). On forested slopes, trees disturbed by snow-avalanches may record in their growth rings information about the past event occurrence. The main aim of this study is to improve the knowledge about the past snow avalanche history using tree-rings approach. To this end, 57 disturbed spruce (Picea abies (L.) Karst.) trees growing along an avalanche path located on the western slopes of the Parâng Mountains were sampled and their growth disturbances (scars, traumatic resin ducts, compression wood and growth suppression sequences) served to reconstruct the snow-avalanche history back to 1950. Tree-ring analyses allowed reconstructing a minimum of 14 snow avalanche events which occurred in the past along the investigated path. The tree-ring approach presented in this study proved to be a valuable tool in reconstructing snow avalanche history and compliting the snow avalanche database in Parâng Mountains. The number and spatial extent of documented snow avalanches evidence the potential snow avalanche hazards in the study area. The tree-ring data from the present study, together with those presented by the previous studies in the study area may further contribute to the snow avalanche hazard assessment. </p>

scholarly journals A Reconstruction of Snow-Avalanche Characteristics in Montana, U.S.A., Using Vegetative Indicators

1985 ◽  
Vol 31 (108) ◽  
pp. 185-187 ◽  
Author(s):  
David R. Butler ◽  
George P. Malanson
Keyword(s):  
Tree Ring ◽  
National Park ◽  
Natural Hazard ◽  
Snow Avalanche ◽  
Glacier National Park ◽  
Snow Avalanches ◽  
Southern Boundary ◽  
Tree Ring Data ◽  
Wet Snow

AbstractWidespread wet-snow avalanches were observed on the southern boundary of Glacier National Park, Montana, in February 1979. Severe tilting, scarring, and breakage of trees were observed along a transverse trim-line of one path, 70 m from a wet-snow deposit. Tree-ring data were used to establish the date of occurrence, and the nature of damage was used to characterize the avalanche event. The event probably included a previously unrecognized dry-snow avalanche and associated wind blast. Such events present different problems for natural-hazard planning. The nature of vegetative damage along the margins of avalanche paths is shown to be a useful indicator of the characteristics of past unobserved avalanche events.

scholarly journals Brief communication: Weak control of snow avalanche deposit volumes by avalanche path morphology

2021 ◽  
Vol 15 (10) ◽  
pp. 4845-4852
Author(s):  
Hippolyte Kern ◽  
Nicolas Eckert ◽  
Vincent Jomelli ◽  
Delphine Grancher ◽  
Michael Deschatres ◽  
...  
Keyword(s):  
Snow Avalanche ◽  
Statistical Techniques ◽  
Snow Avalanches ◽  
Climate Conditions ◽  
French Alps ◽  
Non Linear ◽  
Genesis Of Deposit ◽  
Mechanical Thresholds ◽  
Linear Nature

Abstract. Snow avalanches are a major component of the mountain cryosphere, but little is known about the factors controlling the variability of their deposit volumes. This study investigates the influence of avalanche path morphology on ca. 1500 deposit volumes recorded between 2003 and 2018 in 77 snow avalanche paths of the French Alps. Different statistical techniques show a slight but significant link between deposit volumes and path mean elevation and orientation, with contrasted patterns between winter and spring seasons. The limited and partially non-linear nature of this control may result from the combined influence on the genesis of deposit volumes of mean path activity, climate conditions, and mechanical thresholds determining avalanche release.

scholarly journals Soil erosion and organic carbon export by wet snow avalanches

2014 ◽  
Vol 8 (2) ◽  
pp. 651-658 ◽  
Author(s):  
O. Korup ◽  
C. Rixen
Keyword(s):  
Soil Erosion ◽  
Organic Carbon ◽  
Snow Cover ◽  
Swiss Alps ◽  
Snow Avalanche ◽  
Subalpine Forest ◽  
Snow Avalanches ◽  
Physical Damage ◽  
Wet Snow ◽  
Mountain Belts

Abstract. Many mountain belts sustain prolonged snow cover for parts of the year, although enquiries into rates of erosion in these landscapes have focused almost exclusively on the snow-free periods. This raises the question of whether annual snow cover contributes significantly to modulating rates of erosion in high-relief terrain. In this context, the sudden release of snow avalanches is a frequent and potentially relevant process, judging from the physical damage to subalpine forest ecosystems, and the amount of debris contained in avalanche deposits. To quantitatively constrain this visual impression and to expand the sparse literature, we sampled sediment concentrations of n = 28 river-spanning snow-avalanche deposits (snow bridges) in the area around Davos, eastern Swiss Alps, and inferred an orders-of-magnitude variability in specific fine sediment and organic carbon yields (1.8 to 830 t km−2 yr−1, and 0.04 to 131 t C km−2 yr−1, respectively). A Monte Carlo simulation demonstrates that, with a minimum of free parameters, such variability is inherent to the geometric scaling used for computing specific yields. Moreover, the widely applied method of linearly extrapolating plot scale sample data may be prone to substantial under- or overestimates. A comparison of our inferred yields with previously published work demonstrates the relevance of wet snow avalanches as prominent agents of soil erosion and transporters of biogeochemical constituents to mountain rivers. Given that a number of snow bridges persisted below the insulating debris cover well into the summer months, snow-avalanche deposits also contribute to regulating in-channel sediment and organic debris storage on seasonal timescales. Finally, our results underline the potential shortcomings of neglecting erosional processes in the winter and spring months in mountainous terrain subjected to prominent snow cover.

scholarly journals Soil erosion and organic carbon export by wet snow avalanches

2014 ◽  
Vol 8 (1) ◽  
pp. 1-19 ◽  
Author(s):  
O. Korup ◽  
C. Rixen
Keyword(s):  
Soil Erosion ◽  
Organic Carbon ◽  
Snow Cover ◽  
Swiss Alps ◽  
Snow Avalanche ◽  
Subalpine Forest ◽  
Snow Avalanches ◽  
Physical Damage ◽  
Wet Snow ◽  
Mountain Belts

Abstract. Many mountain belts sustain prolonged snow cover for parts of the year, although enquiries into rates of erosion in these landscapes have focused almost exclusively on the snow-free periods. This raises the question of whether annual snow cover contributes significantly to modulating rates of erosion in high-relief terrain. In this context, the sudden release of snow avalanches is a frequent and potentially relevant process, judging from the physical damage to subalpine forest ecosystems, and the amount of debris contained in avalanche deposits. To quantitatively constrain this visual impression and to expand the sparse existing literature, we sampled sediment concentrations of n = 28 river-spanning snow-avalanche deposits (snow bridges) in the eastern Swiss Alps, and infer an orders-of-magnitude variability in specific fine sediment and organic carbon yields (1.8 to 830 t km−2 yr−1, and 0.04 to 131 t C km−2 yr−1, respectively). A Monte Carlo simulation demonstrates that, with a minimum of free parameters, such variability is inherent to the geometric scaling used for computing specific yields. Moreover, the widely applied method of linearly extrapolating plot-scale sample data may be prone to substantial under- or over-estimates. A comparison of our inferred yields with previously published work demonstrates the relevance of wet snow avalanches as prominent agents of soil erosion and transporters of biogeochemical constituents to mountain rivers. Given that a number of snow bridges persisted below the insulating debris cover well into the summer months, snow-avalanche deposits also contribute to regulating in-channel sediment and organic debris storage on seasonal timescales. Finally, our results underline the potential shortcomings of neglecting erosional processes in the winter and spring months in mountainous terrain subjected to prominent snow cover.

scholarly journals Validating numerical simulations of snow avalanches using dendrochronology: the Cerro Ventana event in Northern Patagonia, Argentina

2008 ◽  
Vol 8 (3) ◽  
pp. 433-443 ◽  
Author(s):  
A. Casteller ◽  
M. Christen ◽  
R. Villalba ◽  
H. Martínez ◽  
V. Stöckli ◽  
...  
Keyword(s):  
Tree Ring ◽  
Model Simulation ◽  
Snow Avalanche ◽  
Future Research ◽  
Nothofagus Pumilio ◽  
Snow Avalanches ◽  
Northern Patagonia ◽  
Digital Elevation ◽  
History Of ◽  
Elevation Model

Abstract. The damage caused by snow avalanches to property and human lives is underestimated in many regions around the world, especially where this natural hazard remains poorly documented. One such region is the Argentinean Andes, where numerous settlements are threatened almost every winter by large snow avalanches. On 1 September 2002, the largest tragedy in the history of Argentinean mountaineering took place at Cerro Ventana, Northern Patagonia: nine persons were killed and seven others injured by a snow avalanche. In this paper, we combine both numerical modeling and dendrochronological investigations to reconstruct this event. Using information released by local governmental authorities and compiled in the field, the avalanche event was numerically simulated using the avalanche dynamics programs AVAL-1D and RAMMS. Avalanche characteristics, such as extent and date were determined using dendrochronological techniques. Model simulation results were compared with documentary and tree-ring evidences for the 2002 event. Our results show a good agreement between the simulated projection of the avalanche and its reconstructed extent using tree-ring records. Differences between the observed and the simulated avalanche, principally related to the snow height deposition in the run-out zone, are mostly attributed to the low resolution of the digital elevation model used to represent the valley topography. The main contributions of this study are (1) to provide the first calibration of numerical avalanche models for the Patagonian Andes and (2) to highlight the potential of Nothofagus pumilio tree-ring records to reconstruct past snow-avalanche events in time and space. Future research should focus on testing this combined approach in other forested regions of the Andes.

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