scholarly journals Modelling wet snow avalanche runout to assess road safety at a high-altitude mine in the central Andes

2016 ◽  
Vol 16 (11) ◽  
pp. 2303-2323 ◽  
Author(s):  
Cesar Vera Valero ◽  
Nander Wever ◽  
Yves Bühler ◽  
Lukas Stoffel ◽  
Stefan Margreth ◽  
...  
Keyword(s):  
High Altitude ◽  
Snow Cover ◽  
Three Dimensional ◽  
Central Andes ◽  
Early Spring ◽  
Avalanche Dynamics ◽  
Wet Snow ◽  
Dynamics Modelling ◽  
Snow Conditions ◽  
Del Rio

Abstract. Mining activities in cold regions are vulnerable to snow avalanches. Unlike operational facilities, which can be constructed in secure locations outside the reach of avalanches, access roads are often susceptible to being cut, leading to mine closures and significant financial losses. In this paper we discuss the application of avalanche runout modelling to predict the operational risk to mining roads, a long-standing problem for mines in high-altitude, snowy regions. We study the 35 km long road located in the "Cajón del rio Blanco" valley in the central Andes, which is operated by the Codelco Andina copper mine. In winter and early spring, this road is threatened by over 100 avalanche paths. If the release and snow cover conditions can be accurately specified, we find that avalanche dynamics modelling is able to represent runout, and safe traffic zones can be identified. We apply a detailed, physics-based snow cover model to calculate snow temperature, density and moisture content in three-dimensional terrain. This information is used to determine the initial and boundary conditions of the avalanche dynamics model. Of particular importance is the assessment of the current snow conditions along the avalanche tracks, which define the mass and thermal energy entrainment rates and therefore the possibility of avalanche growth and long runout distances.

scholarly journals Modelling wet snow avalanche runout to assess road safety at a high-altitude mine in the central Andes

2016 ◽  
Author(s):  
Cesar Vera Valero ◽  
Nander Wever ◽  
Yves Bühler ◽  
Lukas Stoffel ◽  
Stefan Margreth ◽  
...  
Keyword(s):  
High Altitude ◽  
Three Dimensional ◽  
Central Andes ◽  
Early Spring ◽  
Avalanche Dynamics ◽  
Wet Snow ◽  
Dynamics Modelling ◽  
Snow Conditions ◽  
Del Rio ◽  
Snow Temperature

Abstract. Mining activities in cold regions are vulnerable to snow avalanches. Unlike operational facilities, which can be constructed in secure locations outside the reach of avalanches, access roads are often susceptible to being cut, leading to mine closures and significant financial losses. In this paper we discuss the application of avalanche runout modelling to predict the operational risk to mining roads, a longstanding problem for mines in high-altitude, snowy regions. We study the 35 km long road located in the "Cajon del Rio Blanco" valley in the central Andes which is operated by the Codelco Andina copper mine. In winter and early spring this road is threatened by over 100 avalanche paths. If the release and snowcover conditions can be accurately specified, we find that avalanche dynamics modelling is able to represent runout and safe traffic zones can be identified. We apply a detailed, physics based snowcover model to predict snow temperature, density and moisture content in three-dimensional terrain. This information is used to determine the initial and boundary conditions of the avalanche dynamics model. Of particular importance is the assesment of the current snow conditions along the avalanche tracks which define the mass and thermal energy entrainment rates and therefore the possibility of avalanche growth and long runout distances.

Studies on lichen-dominated systems. XI. Lichen–heath and winter snow cover

1975 ◽  
Vol 53 (7) ◽  
pp. 621-626 ◽  
Author(s):  
D. W. Larson ◽  
K. A. Kershaw
Keyword(s):  
Snow Cover ◽  
Early Spring ◽  
Late Winter ◽  
Potential Importance ◽  
Beach Ridges ◽  
Winter Snow ◽  
Forested Areas ◽  
Sedge Meadows ◽  
Snow Conditions

Several tundra beach ridges, adjacent sedge meadows, and forested areas some distance inland were examined in midwinter, late winter, and early spring to assess the potential importance of variations in snow cover to the underlying vegetation.Tops of beach ridges were found to be nearly snow-free all winter and were fully exposed early in the spring. Sedge meadows and forested areas had a thicker cover.The vegetational characteristics of each area appear adapted to the winter snow conditions.

scholarly journals Measurements of mid-winter spatial distribution of meltwater saturation

2010 ◽  
Vol 51 (54) ◽  
pp. 146-152
Author(s):  
J.C. Kapil ◽  
Anupam Kumar ◽  
P.S. Negi
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Snow Cover ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Dielectric Measurement ◽  
Snow Stratigraphy ◽  
Wet Snow ◽  
Water Contents ◽  
Saturation Profiles

AbstractUnder melt–freeze conditions crusts may evolve within a snowpack, which may favour avalanche initiation by forming a hard bed surface for weakly bonded faceted grains. We used a parallel-probe saturation profiler (PPSP) to record the distribution of water contents within the snowpack. Diurnal effects of melt–freeze action on the growth of crusts were monitored with the help of the PPSP device. Saturation profiles were collected from a partially wet snow cover. Snow stratigraphy was conducted manually in the morning, after overnight freezing, to identify the location and the granular compositions of the crusts that had evolved. A one-to-one correspondence between the saturation spikes collected using the PPSP and the actual positions of the crusts was established. The PPSP was also used to monitor three-dimensional variations in the maximum percolation depths within a south-facing snowpack. The operation of the PPSP is faster than existing dielectric measurement techniques, so it was applied to study the spatial variability of maximum percolation depths on the slopes of different aspects.

scholarly journals Remote Sensing of Snow Cover Using Spaceborne SAR: A Review

2019 ◽  
Vol 11 (12) ◽  
pp. 1456 ◽  
Author(s):  
Ya-Lun S. Tsai ◽  
Andreas Dietz ◽  
Natascha Oppelt ◽  
Claudia Kuenzer
Keyword(s):  
Remote Sensing ◽  
Snow Cover ◽  
Meteorological Data ◽  
Weather Condition ◽  
Natural Phenomenon ◽  
Snow Cover Extent ◽  
Wet Snow ◽  
Snow Conditions ◽  
Interferometric Sar ◽  
Processing Techniques

The importance of snow cover extent (SCE) has been proven to strongly link with various natural phenomenon and human activities; consequently, monitoring snow cover is one the most critical topics in studying and understanding the cryosphere. As snow cover can vary significantly within short time spans and often extends over vast areas, spaceborne remote sensing constitutes an efficient observation technique to track it continuously. However, as optical imagery is limited by cloud cover and polar darkness, synthetic aperture radar (SAR) attracted more attention for its ability to sense day-and-night under any cloud and weather condition. In addition to widely applied backscattering-based method, thanks to the advancements of spaceborne SAR sensors and image processing techniques, many new approaches based on interferometric SAR (InSAR) and polarimetric SAR (PolSAR) have been developed since the launch of ERS-1 in 1991 to monitor snow cover under both dry and wet snow conditions. Critical auxiliary data including DEM, land cover information, and local meteorological data have also been explored to aid the snow cover analysis. This review presents an overview of existing studies and discusses the advantages, constraints, and trajectories of the current developments.

scholarly journals Projected changes of snow conditions and avalanche activity in a warming climate: the French Alps over the 2020–2050 and 2070–2100 periods

2014 ◽  
Vol 8 (5) ◽  
pp. 1673-1697 ◽  
Author(s):  
H. Castebrunet ◽  
N. Eckert ◽  
G. Giraud ◽  
Y. Durand ◽  
S. Morin
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
21St Century ◽  
Mitigation Strategies ◽  
Climate Change Scenarios ◽  
Stability Estimates ◽  
Reference Period ◽  
French Alps ◽  
Wet Snow ◽  
Snow Conditions

Abstract. Projecting changes in snow cover due to climate warming is important for many societal issues, including the adaptation of avalanche risk mitigation strategies. Efficient modelling of future snow cover requires high resolution to properly resolve the topography. Here, we introduce results obtained through statistical downscaling techniques allowing simulations of future snowpack conditions including mechanical stability estimates for the mid and late 21st century in the French Alps under three climate change scenarios. Refined statistical descriptions of snowpack characteristics are provided in comparison to a 1960–1990 reference period, including latitudinal, altitudinal and seasonal gradients. These results are then used to feed a statistical model relating avalanche activity to snow and meteorological conditions, so as to produce the first projection on annual/seasonal timescales of future natural avalanche activity based on past observations. The resulting statistical indicators are fundamental for the mountain economy in terms of anticipation of changes. Whereas precipitation is expected to remain quite stationary, temperature increase interacting with topography will constrain the evolution of snow-related variables on all considered spatio-temporal scales and will, in particular, lead to a reduction of the dry snowpack and an increase of the wet snowpack. Overall, compared to the reference period, changes are strong for the end of the 21st century, but already significant for the mid century. Changes in winter are less important than in spring, but wet-snow conditions are projected to appear at high elevations earlier in the season. At the same altitude, the southern French Alps will not be significantly more affected than the northern French Alps, which means that the snowpack will be preserved for longer in the southern massifs which are higher on average. Regarding avalanche activity, a general decrease in mean (20–30%) and interannual variability is projected. These changes are relatively strong compared to changes in snow and meteorological variables. The decrease is amplified in spring and at low altitude. In contrast, an increase in avalanche activity is expected in winter at high altitude because of conditions favourable to wet-snow avalanches earlier in the season. Comparison with the outputs of the deterministic avalanche hazard model MEPRA (Modèle Expert d'aide à la Prévision du Risque d'Avalanche) shows generally consistent results but suggests that, even if the frequency of winters with high avalanche activity is clearly projected to decrease, the decreasing trend may be less strong and smooth than suggested by the statistical analysis based on changes in snowpack characteristics and their links to avalanches observations in the past. This important point for risk assessment pleads for further work focusing on shorter timescales. Finally, the small differences between different climate change scenarios show the robustness of the predicted avalanche activity changes.

scholarly journals Projected changes of snow conditions and avalanche activity in a warming climate: a case study in the French Alps over the 2020–2050 and 2070–2100 periods

2014 ◽  
Vol 8 (1) ◽  
pp. 581-640 ◽  
Author(s):  
H. Castebrunet ◽  
N. Eckert ◽  
G. Giraud ◽  
Y. Durand ◽  
S. Morin
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Time Scales ◽  
21St Century ◽  
Mitigation Strategies ◽  
Climate Change Scenarios ◽  
Reference Period ◽  
French Alps ◽  
Wet Snow ◽  
Snow Conditions

Abstract. Projecting changes in snow cover due to climate warming is important for many societal issues, including adaptation of avalanche risk mitigation strategies. Efficient modeling of future snow cover requires high resolution to properly resolve the topography. Here, we detail results obtained through statistical downscaling techniques allowing simulations of future snowpack conditions for the mid- and late 21st century in the French Alps under three climate change scenarios. Refined statistical descriptions of snowpack characteristics are provided with regards to a 1960–1990 reference period, including latitudinal, altitudinal and seasonal gradients. These results are then used to feed a statistical model of avalanche activity–snow conditions–meteorological conditions relationships, so as to produce the first prognoses at annual/seasonal time scales of future natural avalanche activity eventually based on past observations. The resulting statistical indicators are fundamental for the mountain economy in terms of changes anticipation. At all considered spatio-temporal scales, whereas precipitations are expected to remain quite stationary, temperature increase interacting with topography will control snow-related variables, for instance the rate of decrease of total and dry snow depths, and the successive increase/decrease of the wet snow pack. Overall, with regards to the reference period, changes are strong for the end of the 21st century, but already significant for the mid-century. Changes in winter are somewhat less important than in spring, but wet snow conditions will appear at high elevations earlier in the season. For a given altitude, the Southern French Alps will not be significantly more affected than the Northern French Alps, so that the snowpack characteristics will be preserved more lately in the southern massifs of higher mean altitude. Regarding avalanche activity, a general −20–30% decrease and interannual variability is forecasted, relatively strong compared to snow and meteorological parameters changes. This decrease is amplified in spring and at low altitude. In contrast, an increase of avalanche activity is expected in winter at high altitude because of earlier wet snow avalanches triggers, at least as long as a minimal snow cover will be present. Comparison with the outputs of the deterministic avalanche hazard model MEPRA shows generally consistent results but suggests that, even if the frequency of winters with high avalanche activity will clearly decrease, the decreasing trend may be less strong and smooth than suggested by the changes in snowpack characteristics. This important point for risk assessment pleads for further work focusing on shorter time scales. Finally, small differences between different climate change scenarios show the robustness of the predicted avalanche activity changes.

Inca “Stone Ancestors” in Context at a High-Altitude Usnu Platform

2010 ◽  
Vol 21 (2) ◽  
pp. 173-194 ◽  
Author(s):  
Frank M. Meddens ◽  
Colin McEwan ◽  
Cirilo Vivanco Pomacanchari
Keyword(s):  
High Altitude ◽  
Central Andes ◽  
Vertical Shaft ◽  
Original Surface ◽  
Small Basin

AbstractRecent investigations at mountaintop sites around the Ayacucho Basin in the central Andes have identified a distinctive category of isolated Inca stone-faced platforms. Test excavations of the three-tiered platform at one site, Incapirqa/Waminan, revealed a narrow vertical shaft penetrating from the original surface through the fills to a small basin cut into the underlying andesite bedrock. A carefully arranged deposit of three unusual stones was found in this basin. Early Spanish chroniclers give firsthand accounts of a variety of Inca solar rituals observed in Cuzco in which revered objects were deployed, including some sculpted in stone. The detailed descriptions of these stone objects are corroborated by the excavated finds at Incapirqa/Waminan and offer suggestive analogies for interpreting their context and significance.

The future of ski resorts in the Swiss Alps: using DMDU to identify tipping points

2021 ◽  
Author(s):  
Saeid Ashraf Vaghefi ◽  
Veruska Muccione ◽  
Kees C.H. van Ginkel ◽  
Marjolijn Haasnoot
Keyword(s):  
Snow Cover ◽  
Climate Models ◽  
Swiss Alps ◽  
Tipping Points ◽  
Annual Variability ◽  
Ski Resorts ◽  
The Future ◽  
Total Profit ◽  
Climate Uncertainty ◽  
Snow Conditions

<p>The future of ski resorts in the Swiss Alps is highly uncertain. Being dependent on snow cover conditions, winter sport tourism is highly susceptible to changes in temperature and precipitation. With the observed warming of the European Alps being well above global average warming, snow cover in Switzerland is projected to shrink at a rapid pace. Climate uncertainty originates from greenhouse gas emission trajectories (RCPs) and differences between climate models. Beyond climate uncertainty, the snow conditions are strongly subject to intra-annual variability. Series of unfavorable years have already led to the financial collapse of several low-altitude ski resorts. Such abrupt collapses with a large impact on the regional economy can be referred to as climate change induced socio-economic tipping points. To some degree, tipping points may be avoided by adaptation measures such as artificial snowmaking, although these measures are also subject to physical and economical constraints. In this study, we use a variety of exploratory modeling techniques to identify tipping points in a coupled physical-economic model applied to six representative ski resorts in the Swiss Alps. New high-resolution climate projections (CH2018) are used to represent climate uncertainty. To improve the coverage of the uncertainty space and accounting for the intra-annual variability of the climate models, a resampling technique was used to produce new climate realizations. A snow process model is used to simulate daily snow-cover in each of the ski resorts. The likelihood of survival of each resort is evaluated from the number of days with good snow conditions for skiing compared to the minimum thresholds obtained from the literature. Economically, the good snow days are translated into the total profit of ski resorts per season of operation. Multiple unfavorable years of total profit may lead to a tipping point. We use scenario discovery to identify the conditions under which these tipping points occur, and reflect on their implications for the future of snow tourism in the Swiss Alps.</p>

scholarly journals A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years

2016 ◽  
Vol 12 (5) ◽  
pp. 1165-1180 ◽  
Author(s):  
Karsten Schittek ◽  
Sebastian T. Kock ◽  
Andreas Lücke ◽  
Jonathan Hense ◽  
Christian Ohlendorf ◽  
...  
Keyword(s):  
High Altitude ◽  
Environmental Changes ◽  
Regional Scale ◽  
Central Andes ◽  
High Accumulation ◽  
Climate Conditions ◽  
Climate Anomalies ◽  
Dry Conditions ◽  
Induced Changes ◽  
The 19Th Century

Abstract. High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650–800 and AD  1000–1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.

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