scholarly journals Snow gliding and glide-snow avalanches: recent outcomes from two experimental test sites in Aosta Valley (northwestern Italian Alps)

2019 ◽  
Vol 19 (11) ◽  
pp. 2667-2676 ◽  
Author(s):  
Margherita Maggioni ◽  
Danilo Godone ◽  
Barbara Frigo ◽  
Michele Freppaz
Keyword(s):  
Experimental Test ◽  
Interdisciplinary Approach ◽  
Liquid Water Content ◽  
Driving Factors ◽  
Soil Conditions ◽  
Snow Avalanches ◽  
Exponential Relationship ◽  
Weather Parameters ◽  
Nw Italy ◽  
Snow Gliding

Abstract. Snow gliding and glide-snow avalanches are gaining importance among scientists as global warming might induce conditions favourable to those phenomena. Our aim is to analyse such processes with a particular focus on the potential driving factors associated with the soil conditions. We equipped two experimental test sites in the Aosta Valley region (NW Italy) with glide-snow shoes, temperature and volumetric liquid water content (VLWC) sensors in the soil and in the basal snowpack layer; snow and weather parameters were also collected by automatic weather stations and at manual snow measuring sites. In the two monitoring seasons 2013–2014 and 2014–2015 we registered nine glide-snow avalanches, two cold and seven warm events, which were characterized by different snow and soil conditions. In the only warm glide-snow avalanche event, which presented a continuous gliding before, the daily glide rate showed a significant exponential relationship with the soil VLWC. We also found, though without a general trend, that gliding and non-gliding periods (either considering warm and cold periods separately or together) were characterized by significantly different predisposing factors. This study contributes to the assessment of the importance of soil VLWC, which seems to be one of the most important driving factors for gliding processes. Therefore, it supports the need, already suggested by other scientists, for analysing such processes with an interdisciplinary approach which integrates snow and soil sciences.

scholarly journals Snow gliding and glide snow avalanches: recent outcomes from two experimental test sites in Aosta Valley (NW Italian Alps)

2019 ◽  
Author(s):  
Margherita Maggioni ◽  
Danilo Godone ◽  
Barbara Frigo ◽  
Michele Freppaz
Keyword(s):  
Experimental Test ◽  
Interdisciplinary Approach ◽  
Liquid Water Content ◽  
Driving Factors ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Snow Avalanches ◽  
Exponential Relationship ◽  
Nw Italy ◽  
Snow Gliding

Abstract. Snow gliding and glide snow avalanches are gaining importance among scientists as climate change might induce conditions favourable to those phenomena. Our aim is to analyse such processes with a particular focus on the potential driving factors associated to the soil conditions. We equipped two experimental test sites in Aosta Valley Region (NW-Italy) with glide-snow shoes, temperature and volumetric liquid water content (VLWC) sensors in the soil and in the basal snowpack layer; snow and weather parameters were also collected by automatic weather stations and in manual snow measuring sites. In the two monitoring seasons 2013–14 and 2014–15 we registered 9 glide snow avalanches: 2 cold and 7 warm-temperature events, which were characterized by different snow and soil parameters. In the only warm glide snow avalanche event, which presented a continuous gliding before, the daily glide rate showed a significant exponential relationship with the soil VLWC. We also found, though without a general trend, that gliding and non-gliding periods (either considering warm and cold periods separately or together) were characterized by significantly different predisposing factors. This study contributes to assess the importance of soil VLWC, which seems to be one of the most important driving factors for gliding processes. Therefore, it supports the need, already suggested by other scientists, of analysing such processes with an interdisciplinary approach which integrates snow and soil sciences.

scholarly journals <i>In situ</i> nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

2017 ◽  
Author(s):  
M. Andy Kass ◽  
Trevor P. Irons ◽  
Burke J. Minsley ◽  
Neal J. Pastick ◽  
Dana R. N. Brown ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Active Layer ◽  
Liquid Water ◽  
Interdisciplinary Approach ◽  
Liquid Water Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Nuclear Magnetic

Abstract. Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multi-year investigation into the impacts of wildfires to permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR can image the nucleation of ice within soil pore spaces.

scholarly journals In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

2017 ◽  
Vol 11 (6) ◽  
pp. 2943-2955 ◽  
Author(s):  
M. Andy Kass ◽  
Trevor P. Irons ◽  
Burke J. Minsley ◽  
Neal J. Pastick ◽  
Dana R. N. Brown ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Active Layer ◽  
Liquid Water ◽  
Interdisciplinary Approach ◽  
Liquid Water Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Nuclear Magnetic

Abstract. Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multiyear investigation into the impacts of wildfires on permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show the efficacy of borehole NMR (bNMR) to permafrost studies. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR is sensitive to the nucleation of ice within soil pore spaces.

scholarly journals Soil Erosion Caused by Snow Avalanches: a Case Study in the Aosta Valley (NW Italy)

2010 ◽  
Vol 42 (4) ◽  
pp. 412-421 ◽  
Author(s):  
Michele Freppaz ◽  
Danilo Godone ◽  
Gianluca Filippa ◽  
Margherita Maggioni ◽  
Stefano Lunardi ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Snow Avalanches ◽  
Nw Italy

Numerical simulations of wet snow avalanches: interplay between cohesion and friction

2021 ◽  
Author(s):  
Guillaume Chambon ◽  
Thierry Faug ◽  
Mohamed Naaim
Keyword(s):  
Numerical Simulations ◽  
Flow Regimes ◽  
Liquid Water Content ◽  
Snow Avalanches ◽  
Shallow Flow ◽  
Distinctive Features ◽  
Wide Range ◽  
Wet Snow ◽  
Sensitivity Studies ◽  
Avalanche Flow

&lt;p&gt;Wet snow avalanches present distinctive features such as unusual trajectories, peculiar deposit shapes, and a rheological behavior displaying a combination of granular and pasty features depending on the actual snow liquid water content. Complex transitions between dry (cold) and wet (hot) flow regimes can also occur during a single avalanche flow. In an attempt to account for this complexity, we report on numerical simulations of avalanches using a frictional-cohesive rheology implemented in a depth-averaged shallow-flow model. Through extensive sensitivity studies on synthetic and real topographies, we show that cohesion plays a key role to enrich the physics of the simulated flows, and to represent realistic avalanche behaviors. First, when coupled to a proper treatment of the yielding criterion, cohesion provides a way to define objective stopping criteria for the flow, independently of the issues incurred by artificial diffusion of the numerical scheme. Second, and more importantly, the interplay between cohesion and friction gives raise to a variety of nontrivial physical effects affecting the dynamics of the avalanches and the morphology of the deposits. The relative weights of frictional and cohesive contributions to the overall stress are investigated as a function of space and time during the propagation, and related to the formation of specific features such as lateral lev&amp;#233;es, hydraulic jumps, etc. This study represents a first step towards robust avalanches simulations, spanning the wide range of possible flow regimes, through shallow-flow approaches. Future improvements involving more refined cohesion parameterizations will be discussed.&lt;/p&gt;

scholarly journals An outline of avalanches in the Tien Shan mountains

1992 ◽  
Vol 16 ◽  
pp. 7-10 ◽  
Author(s):  
Hu Ruji ◽  
Ma Hong ◽  
Wang Guo
Keyword(s):  
Snow Cover ◽  
Basal Layer ◽  
Liquid Water Content ◽  
Snow Accumulation ◽  
Tien Shan ◽  
Large Temperature ◽  
Snow Avalanches ◽  
Climatic Variations ◽  
Tien Shan Mountains ◽  
Seasonal Snow Cover

The seasonal snow cover in the Tien Shan mountains is characterized by low density, low liquid-water content and low temperature. It is known as typical dry snow. Large temperature gradients in the basal layer of the snow cover exist throughout the entire period of snow accumulation, and depth hoar is therefore extremely well-developed. Full-depth depth-hoar avalanches, however, seldom occur. Avalanches in the Tien Shan mountains are mostly loose snow avalanches. Although normally not large in size, they are the most dangerous type. The occurrence of hazardous avalanches shows cycles of about ten years because of periodic climatic variations.

scholarly journals Operative Monographies: Development of a New Tool for the Effective Management of Landslide Risks

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 485 ◽  
Author(s):  
Daniele Giordan ◽  
Martina Cignetti ◽  
Aleksandra Wrzesniak ◽  
Paolo Allasia ◽  
Davide Bertolo
Keyword(s):  
Urban Areas ◽  
Interdisciplinary Approach ◽  
Civil Aviation ◽  
Landslide Risk ◽  
Effective Management ◽  
Standard Format ◽  
Hazard Management ◽  
Efficient Management ◽  
Long Time ◽  
Nw Italy

Active landslide risk assessment and management are primarily based on the availability of dedicated studies and monitoring activities. The establishment of decision support for the efficient management of active landslides threatening urban areas is a worthwhile contribution. Nowadays, consistent information about major landslide hazards is obtained through an interdisciplinary approach, consisting of field survey data and long-time monitoring, with the creation of a high populated dataset. Nevertheless, the large number and variety of acquired data can generate some criticalities in their management. Data fragmentation and a missing standard format of the data should represent a serious hitch in landslide hazard management. A good organization in a standard format can be a good operative solution. Based on standardized approaches such as the ICAO (International Civil Aviation Organization), we developed a standard document called operative monography. This document summarizes all available information by organizing monitoring data and identifying possible lacks. We tested this approach in the Aosta Valley Region (NW Italy) on five different slow moving landslides monitored for twenty years. The critical analysis of the available dataset modifies a simple sequence of information in a more complex document, adoptable by local and national authorities for a more effective management of active landslides.

scholarly journals The role of soil volumetric liquid water content during snow gliding processes

2017 ◽  
Vol 136 ◽  
pp. 17-29 ◽  
Author(s):  
Elisabetta Ceaglio ◽  
Christoph Mitterer ◽  
Margherita Maggioni ◽  
Stefano Ferraris ◽  
Valerio Segor ◽  
...  
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Liquid Water Content ◽  
Snow Gliding

Simulating the propagation of wet snow avalanches: challenges and perspectives

2020 ◽  
Author(s):  
Guillaume Chambon ◽  
Thierry Faug ◽  
Mohamed Naaim ◽  
Nicolas Eckert
Keyword(s):  
Numerical Models ◽  
Flow Simulation ◽  
Liquid Water Content ◽  
Snow Avalanches ◽  
Shallow Flow ◽  
Simulation Code ◽  
Full Spectrum ◽  
Wet Snow ◽  
Sensitivity Studies ◽  
Smooth Transitions

&lt;p&gt;Recent winters saw a striking increase in wet snow avalanche activity. Compared to dry avalanches, wet snow avalanches present uniquely distinctive features such as slower velocities, larger depths, unusual trajectories and deposit shapes, and a paste-like rheology that can result in large shear and normal stresses. In addition, the behavior of wet avalanches may strongly vary depending on the actual snow liquid water content. Complex transitions between dry (cold) and wet (hot) behaviors have also been observed during the propagation of single avalanche events. Current numerical models of avalanche dynamics are challenged when it comes to capturing the full spectrum of these different regimes, and the transitions in between. In this contribution, we critically review the various rheological models that have been proposed in the literature to simulate dry and wet snow avalanches in the frame of depth-averaged shallow-flow approaches. On this basis, a simplified parametric rheological law is proposed, with the objective of representing both dry-like and wet-like behaviors and allowing for smooth transitions between them. The law is implemented in a robust 2D shallow-flow simulation code, and systematic sensitivity studies are performed on synthetic and real topographies. Simulation outcomes are analysed in terms of propagation dynamics and deposition patterns, and the ability of the model to capture both dry and wet regimes is discussed. Lastly, a specific calibration methodology is proposed to infer the relevant mechanical parameters from documented avalanche events.&lt;/p&gt;

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