scholarly journals Mapping hazards from glacier lake outburst floods based on modelling of process cascades at Lake 513, Carhuaz, Peru

2014 ◽  
Vol 35 ◽  
pp. 145-155 ◽  
Author(s):  
D. Schneider ◽  
C. Huggel ◽  
A. Cochachin ◽  
S. Guillén ◽  
J. García

Abstract. Recent warming has had enormous impacts on glaciers and high-mountain environments. Hazards have changed or new ones have emerged, including those from glacier lakes that form as glaciers retreat. The Andes of Peru have repeatedly been severely impacted by glacier lake outburst floods in the past. An important recent event occurred in the Cordillera Blanca in 2010 when an ice avalanche impacted a glacier lake and triggered an outburst flood that affected the downstream communities and city of Carhuaz. In this study we evaluate how such complex cascades of mass movement processes can be simulated coupling different physically-based numerical models. We furthermore develop an approach that allows us to elaborate corresponding hazard maps according to existing guidelines for debris flows and based on modelling results and field work.

2021 ◽  
Author(s):  
Sandra Gorsic ◽  
Alberto Muñoz-Torrero Manchado ◽  
Jérôme Lopez-Saez ◽  
Simon K. Allen ◽  
Juan A. Ballesteros-Canovas ◽  
...  

<p>With the substantial glacier mass reduction projected by the end of the century, the formation and rise of periglacial lakes has to be expected. Even though these changes often occur in remote areas, they can nevertheless have catastrophic impacts on populations and infrastructure through processes such as glacial lake outburst floods (GLOF). GLOFs are the result of complex geomorphic changes and subject to various timescales, thus urging the need for a multidimensional approach. The present study combines two approaches to analyze natural hazards in the secluded San Rafael National Park in Chilean Patagonia (North Patagonian Icefield). The Grosse glacier outlet was chosen after interpreting satellite imagery and historical pictures showing a historical emptying of a lateral lake, which was also supported by local testimonies. Dendrogeomorphology was primarily used with an automatic detection approach to identify possible dates of occurrence of past GLOFs at the Grosse outlet. A total of 105 disturbed Nothofagus trees were sampled highlighting 6 event years between 1958 and 2011. The second method aimed at complementing the tree-ring-based findings with UAV imagery acquired during fieldwork and the mapping of geomorphic evidence of past GLOFs. Huge boulders and deposits are one of the signs recognized as remnants of past lake outbursts and were thus used to differentiate small, rainfall-induced floods from high magnitude events. More precisely, through an object-based strategy, we mapped deposits and extrapolated a theoretical flow orientation. Whereas the first method allowed to select dates of potential events, the second facilitated identification and mapping of the spatial extent of past high-energy events. Analysis of imagery also allowed detection of the occurrence of a 200-m wide breach in the frontal moraine as well as the vanishing of a lateral lake estimated to be 1.8 × 10<sup>6 </sup>m<sup>2</sup> in the 1950s, which we date to 1958 using tree-ring records. When used together the two approaches can represent a valuable contribution to historical records and help future assessments of natural hazard at Grosse glacier, but also in other high-mountain environments.</p>


2017 ◽  
Author(s):  
Judith Eeckman ◽  
Santosh Nepal ◽  
Pierre Chevallier ◽  
Gauthier Camensuli ◽  
Francois Delclaux ◽  
...  

Abstract. Understanding hydrological processes of high-altitude areas is vital because downstream communities depend on water resources for their livelihood. This paper compares the hydrological responses at the local scale of two models using different degrees of refinement to represent physical processes in sparsely instrumented mountainous Himalayan catchments. Two small catchments located in mid- and high- mountain environments were chosen to represent the very different climatic and physiographic characteristics of the Central Himalayas in the Everest region of eastern Nepal. This work presents the novelty of applying, at a small spatio-temporal scale and under the same forcing conditions, a fully distributed surface scheme based on mass and energy balance equations (ISBA surface scheme), and a semi-distributed calibrated model (J2000 hydrological model). A new conceptual module coupled to the ISBA surface scheme for flow routing is presented. The results show that both models describe the evapotranspiration, quick runoff and discharge processes in a similar way. The reliability of the simulations for these variables can therefore be considered as satisfactory. The differences in the structure and results of the two models mainly concern the water storage and flows in the soil, in particular for the high-mountain catchment. This conclusion suggests that the uncertainty associated with model structure is significant for water storage and flow in the soil.


2021 ◽  
pp. 1-18
Author(s):  
Wilhelm Furian ◽  
David Loibl ◽  
Christoph Schneider

Abstract Bedrock overdeepenings exposed by continued glacial retreat can store precipitation and meltwater, potentially leading to the formation of new proglacial lakes. These lakes may pose threats of glacial lake outburst floods (GLOFs) in high mountain areas, particularly if new lakes form in geomorphological setups prone to triggering events such as landslides or moraine collapses. We present the first complete inventory for future glacial lakes in High Mountain Asia by computing the subglacial bedrock for ~100 000 glaciers and estimating overdeepening area, volume and impact hazard for the larger potential lakes. We detect 25 285 overdeepenings larger than 104 m2 with a volume of 99.1 ± 28.6 km3 covering an area of 2683 ± 773.8 km2. For the 2700 overdeepenings larger than 105 m2, we assess the lake predisposition for mass-movement impacts that could trigger a GLOF by estimating the hazard of material detaching from surrounding slopes. Our findings indicate a shift in lake area, volume and GLOF hazard from the southwestern Himalayan region toward the Karakoram. The results of this study can be used for anticipating emerging threats and potentials connected to glacial lakes and as a basis for further studies at suspected GLOF hazard hotspots.


Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 101
Author(s):  
Da Huo ◽  
Zhaohui Chi ◽  
Andong Ma

Surface processes on debris-covered glaciers are governed by a variety of controlling factors including climate, debris load, water bodies, and topography. Currently, we have not achieved a general consensus on the role of supraglacial processes in regulating climate–glacier sensitivity in High Mountain Asia, which is mainly due to a lack of an integrated understanding of glacier surface dynamics as a function of debris properties, mass movement, and ponding. Therefore, further investigations on supraglacial processes is needed in order to provide more accurate assessments of the hydrological cycle, water resources, and natural hazards in the region. Given the scarcity of long-term in situ data and the difficulty of conducting fieldwork on these glaciers, many numerical models have been developed by recent studies. This review summarizes our current knowledge of surface processes on debris-covered glaciers with an emphasis on the related modeling efforts. We present an integrated view on how numerical modeling provide insights into glacier surface ablation, supraglacial debris transport, morphological variation, pond dynamics, and ice-cliff evolution. We also highlight the remote sensing approaches that facilitate modeling, and discuss the limitations of existing models regarding their capabilities to address coupled processes on debris-covered glaciers and suggest research directions.


Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1176
Author(s):  
Massimiliano Fazzini ◽  
Marco Cordeschi ◽  
Cristiano Carabella ◽  
Giorgio Paglia ◽  
Gianluca Esposito ◽  
...  

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.


2014 ◽  
Vol 2 (1) ◽  
pp. 477-533 ◽  
Author(s):  
M. J. Westoby ◽  
J. Brasington ◽  
N. F. Glasser ◽  
M. J. Hambrey ◽  
J. M. Reynolds ◽  
...  

Abstract. The rapid development and instability of moraine-dammed proglacial lakes is increasing the potential for the occurrence of catastrophic Glacial Lake Outburst Floods (GLOFs) in high-mountain regions. Advanced, physically-based numerical dam-breach models represent an improvement over existing methods for the derivation of breach outflow hydrographs. However, significant uncertainty surrounds the initial parameterisation of such models, and remains largely unexplored. We use a unique combination of numerical dam-breach and two-dimensional hydrodynamic modelling, employed with a Generalised Likelihood Uncertainty Estimation (GLUE) framework to quantify the degree of equifinality in dam-breach model output for the reconstruction of the failure of Dig Tsho, Nepal. Monte Carlo analysis was used to sample the model parameter space, and morphological descriptors of the moraine breach were used to evaluate model performance. Equifinal breach morphologies were produced by parameter ensembles associated with differing breach initiation mechanisms, including overtopping waves and mechanical failure of the dam face. The material roughness coefficient was discovered to exert a dominant influence over model performance. Percentile breach hydrographs derived from cumulative distribution function hydrograph data under- or overestimated total hydrograph volume and were deemed to be inappropriate for input to hydrodynamic modelling. Our results support the use of a Total Variation Diminishing solver for outburst flood modelling, which was found to be largely free of numerical instability and flow oscillation. Routing of scenario-specific optimal breach hydrographs revealed prominent differences in the timing and extent of inundation. A GLUE-based method for constructing likelihood-weighted maps of GLOF inundation extent, flow depth, and hazard is presented, and represents an effective tool for communicating uncertainty and equifinality in GLOF hazard assessment. However, future research should focus on the utility of the approach for predictive, as opposed to reconstructive GLOF modelling.


2015 ◽  
Vol 3 (1) ◽  
pp. 171-199 ◽  
Author(s):  
M. J. Westoby ◽  
J. Brasington ◽  
N. F. Glasser ◽  
M. J. Hambrey ◽  
J. M. Reynolds ◽  
...  

Abstract. The instability of moraine-dammed proglacial lakes creates the potential for catastrophic glacial lake outburst floods (GLOFs) in high-mountain regions. In this research, we use a unique combination of numerical dam-breach and two-dimensional hydrodynamic modelling, employed within a generalised likelihood uncertainty estimation (GLUE) framework, to quantify predictive uncertainty in model outputs associated with a reconstruction of the Dig Tsho failure in Nepal. Monte Carlo analysis was used to sample the model parameter space, and morphological descriptors of the moraine breach were used to evaluate model performance. Multiple breach scenarios were produced by differing parameter ensembles associated with a range of breach initiation mechanisms, including overtopping waves and mechanical failure of the dam face. The material roughness coefficient was found to exert a dominant influence over model performance. The downstream routing of scenario-specific breach hydrographs revealed significant differences in the timing and extent of inundation. A GLUE-based methodology for constructing probabilistic maps of inundation extent, flow depth, and hazard is presented and provides a useful tool for communicating uncertainty in GLOF hazard assessment.


Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1376
Author(s):  
Taigang Zhang ◽  
Weicai Wang ◽  
Tanguang Gao ◽  
Baosheng An

A glacial lake outburst flood (GLOF) is a typical glacier-related hazard in high mountain regions. In recent decades, glacial lakes in the Himalayas have expanded rapidly due to climate warming and glacial retreat. Some of these lakes are unstable, and may suddenly burst under different triggering factors, thus draining large amounts of water and impacting downstream social and economic development. Glacial lakes in the Poiqu River basin, Central Himalayas, have attracted great attention since GLOFs originating there could have a transboundary impact on both China and Nepal, as occurred during the Cirenmaco GLOF in 1981 and the Gongbatongshaco GLOF in 2016. Based on previous studies of this basin, we selected seven very high-risk moraine-dammed lakes (Gangxico, Galongco, Jialongco, Cirenmaco, Taraco, Beihu, and Cawuqudenco) to simulate GLOF propagation at different drainage percentage scenarios (i.e., 25%, 50%, 75%, and 100%), and to conduct hazard assessment. The results show that, when any glacial lake is drained completely or partly, most of the floods will enter Nepal after raging in China, and will continue to cause damage. In summary, 57.5 km of roads, 754 buildings, 3.3 km2 of farmland, and 25 bridges are at risk of damage due to GLOFs. The potentially inundated area within the Chinese part of the Poiqu River basin exceeds 45 km2. Due to the destructive impacts of GLOFs on downstream areas, appropriate and effective measures should be implemented to adapt to GLOF risk. We finally present a paradigm for conducting hazard assessment and risk management. It uses only freely available data and thus is easy to apply.


2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Jacqueline Eng ◽  
Mark Aldenderfer

Anthropological research in the high-elevation regions of northwestern Nepal offers insights into the populationhistory of the Himalayan arc through a multi- and interdisciplinary approach that includes not only archaeologicaldata and historic and ethnographic accounts but also genomic, isotopic, and bioarchaeologicaldata, as well as innovative use of thermal niche modeling for paleoclimate reconstruction. Together these linesof evidence have allowed us to address project questions about human settlement into the region, including(1) sources of population movements into high-elevation environments of the Himalayan arc and (2) bioculturaladaptations to high-mountain environments. In this paper we compare research at several communalmortuary sites, each with a rich assemblage of material culture and human burials: Mebrak (400 B.C.–A.D. 50),Kyang (400–175 B.C.), and Samdzong (A.D. 450–650), as well as intriguing insights from finds in the earlier (ca.1250–450 B.C.) sites of Lubrak, Chokhopani, and Rhirhi. Our genomic findings demonstrate population originsfrom the Tibetan plateau, despite South Asian material culture recovered in early sites. Bioarchaeological findingsof low frequencies of non-specific stress and trauma indicate successful biocultural adaptation to highaltitudeconditions of hypoxia, cold, and low resource availability, potentially through buffering from exchangenetworks and local cultural practices, alongside high-altitude selected alleles. An integrative, multidisciplinaryapproach thus offers significantly greater opportunities for developing a more nuanced understanding of thepast processes of migration, settlement, and biocultural adaptation in the region. La investigación antropológica de las alturas del noroeste de Nepal nos proporciona conocimientos de la historiade la población del arco Himalaya a través de un enfoque multidisciplinario e interdisciplinario que incluyeno solamente datos arqueológicos y relatos históricos y etnográficos, sino también datos genómicos, isotópicos,y bioarqueológicos, tanto como uso innovador del modelado del nicho térmico para la reconstrucción paleoclimática.En conjunto, estas líneas de evidencia nos han permitido abordar temas sobre el asentamiento humanade la región, como: (1) los orígenes del movimiento hacia ambientes en las alturas del arco del Himalaya;y (2) las adaptaciones bioculturales necesarias para vivir en las alturas. En este artículo comparamos las investigacionesde varios mortuorios comunales que ofrecen conjuntos abundantes de entierros humanos y artefactosrelacionados: Mebrak (400 a.C.–d.C. 50), Kyang (400–175 a.C.), and Samdzong (d.C. 450–650), así como loshallazgos intrigantes de sitios anteriores (ca. 1250–450 a.C.) de Lubrak, Chokhopani, y Rhirhi. Nuestros datosgenómicos sugieren orígenes de le población del altiplano tibetano, a pesar del material que deriva del sur de Asia que se ha recuperado de los sitios mas tempranos. Los hallazgos bioarqueológicos demuestran niveles bajosde estrés y trauma inespecífico, y sugieren éxito en adaptación biocultural, a pesar de las condiciones de hipoxia,frio, y los recursos escasos en este ambiente. Es posible que alelos seleccionados a las alturas, junto con sistemasde intercambio y las costumbres locales contribuyeron al éxito de la adaptación. Por lo tanto, un enfoque multidisciplinarioque integra todas las evidencias ofrece una comprensión mas detallada de los procesos de migración,asentamiento, y adaptación biocultural de la región.


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