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Journal articles on the topic 'Glacial erosion – Peru – Blanca, Cordillera'

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Published: 4 June 2021

Last updated: 6 February 2022

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1

Mergili, Martin, Shiva P. Pudasaini, Adam Emmer, Jan-Thomas Fischer, Alejo Cochachin, and Holger Frey. "Reconstruction of the 1941 GLOF process chain at Lake Palcacocha (Cordillera Blanca, Peru)." Hydrology and Earth System Sciences 24, no. 1 (January 9, 2020): 93–114. http://dx.doi.org/10.5194/hess-24-93-2020.

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Abstract. The Cordillera Blanca in Peru has been the scene of rapid deglaciation for many decades. One of numerous lakes formed in the front of the retreating glaciers is the moraine-dammed Lake Palcacocha, which drained suddenly due to an unknown cause in 1941. The resulting Glacial Lake Outburst Flood (GLOF) led to dam failure and complete drainage of Lake Jircacocha downstream, and to major destruction and thousands of fatalities in the city of Huaráz at a distance of 23 km. We chose an integrated approach to revisit the 1941 event in terms of topographic reconstruction and numerical back-calculation with the GIS-based open-source mass flow/process chain simulation framework r.avaflow, which builds on an enhanced version of the Pudasaini (2012) two-phase flow model. Thereby we consider four scenarios: (A) and (AX) breach of the moraine dam of Lake Palcacocha due to retrogressive erosion, assuming two different fluid characteristics; (B) failure of the moraine dam caused by the impact of a landslide on the lake; and (C) geomechanical failure and collapse of the moraine dam. The simulations largely yield empirically adequate results with physically plausible parameters, taking the documentation of the 1941 event and previous calculations of future scenarios as reference. Most simulation scenarios indicate travel times between 36 and 70 min to reach Huaráz, accompanied with peak discharges above 10 000 m3 s−1. The results of the scenarios indicate that the most likely initiation mechanism would be retrogressive erosion, possibly triggered by a minor impact wave and/or facilitated by a weak stability condition of the moraine dam. However, the involvement of Lake Jircacocha disguises part of the signal of process initiation farther downstream. Predictive simulations of possible future events have to be based on a larger set of back-calculated GLOF process chains, taking into account the expected parameter uncertainties and appropriate strategies to deal with critical threshold effects.

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2

Somos-Valenzuela, Marcelo A., Rachel E. Chisolm, Denny S. Rivas, Cesar Portocarrero, and Daene C. McKinney. "Modeling a glacial lake outburst flood process chain: the case of Lake Palcacocha and Huaraz, Peru." Hydrology and Earth System Sciences 20, no. 6 (July 1, 2016): 2519–43. http://dx.doi.org/10.5194/hess-20-2519-2016.

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Abstract. One of the consequences of recent glacier recession in the Cordillera Blanca, Peru, is the risk of glacial lake outburst floods (GLOFs) from lakes that have formed at the base of retreating glaciers. GLOFs are often triggered by avalanches falling into glacial lakes, initiating a chain of processes that may culminate in significant inundation and destruction downstream. This paper presents simulations of all of the processes involved in a potential GLOF originating from Lake Palcacocha, the source of a previously catastrophic GLOF on 13 December 1941, killing about 1800 people in the city of Huaraz, Peru. The chain of processes simulated here includes (1) avalanches above the lake; (2) lake dynamics resulting from the avalanche impact, including wave generation, propagation, and run-up across lakes; (3) terminal moraine overtopping and dynamic moraine erosion simulations to determine the possibility of breaching; (4) flood propagation along downstream valleys; and (5) inundation of populated areas. The results of each process feed into simulations of subsequent processes in the chain, finally resulting in estimates of inundation in the city of Huaraz. The results of the inundation simulations were converted into flood intensity and preliminary hazard maps (based on an intensity-likelihood matrix) that may be useful for city planning and regulation. Three avalanche events with volumes ranging from 0.5 to 3 × 106 m3 were simulated, and two scenarios of 15 and 30 m lake lowering were simulated to assess the potential of mitigating the hazard level in Huaraz. For all three avalanche events, three-dimensional hydrodynamic models show large waves generated in the lake from the impact resulting in overtopping of the damming moraine. Despite very high discharge rates (up to 63.4 × 103 m3 s−1), the erosion from the overtopping wave did not result in failure of the damming moraine when simulated with a hydro-morphodynamic model using excessively conservative soil characteristics that provide very little erosion resistance. With the current lake level, all three avalanche events result in inundation in Huaraz due to wave overtopping, and the resulting preliminary hazard map shows a total affected area of 2.01 km2, most of which is in the high hazard category. Lowering the lake has the potential to reduce the affected area by up to 35 %, resulting in a smaller portion of the inundated area in the high hazard category.

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Chisolm, Rachel E., and Daene C. McKinney. "Dynamics of avalanche-generated impulse waves: three-dimensional hydrodynamic simulations and sensitivity analysis." Natural Hazards and Earth System Sciences 18, no. 5 (May 17, 2018): 1373–93. http://dx.doi.org/10.5194/nhess-18-1373-2018.

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Abstract. This paper studies the lake dynamics for avalanche-triggered glacial lake outburst floods (GLOFs) in the Cordillera Blanca mountain range in Ancash, Peru. As new glacial lakes emerge and existing lakes continue to grow, they pose an increasing threat of GLOFs that can be catastrophic to the communities living downstream. In this work, the dynamics of displacement waves produced from avalanches are studied through three-dimensional hydrodynamic simulations of Lake Palcacocha, Peru, with an emphasis on the sensitivity of the lake model to input parameters and boundary conditions. This type of avalanche-generated wave is an important link in the GLOF process chain because there is a high potential for overtopping and erosion of the lake-damming moraine. The lake model was evaluated for sensitivity to turbulence model and grid resolution, and the uncertainty due to these model parameters is significantly less than that due to avalanche boundary condition characteristics. Wave generation from avalanche impact was simulated using two different boundary condition methods. Representation of an avalanche as water flowing into the lake generally resulted in higher peak flows and overtopping volumes than simulating the avalanche impact as mass–momentum inflow at the lake boundary. Three different scenarios of avalanche size were simulated for the current lake conditions, and all resulted in significant overtopping of the lake-damming moraine. Although the lake model introduces significant uncertainty, the avalanche portion of the GLOF process chain is likely to be the greatest source of uncertainty. To aid in evaluation of hazard mitigation alternatives, two scenarios of lake lowering were investigated. While large avalanches produced significant overtopping waves for all lake-lowering scenarios, simulations suggest that it may be possible to contain waves generated from smaller avalanches if the surface of the lake is lowered.

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4

Iturrizaga, Lasafam. "Glacial and glacially conditioned lake types in the Cordillera Blanca, Peru." Progress in Physical Geography: Earth and Environment 38, no. 5 (October 2014): 602–36. http://dx.doi.org/10.1177/0309133314546344.

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The article presents a conceptual approach for the spatiotemporal distribution pattern of principal lake types in the context of the glaciation history in the Cordillera Blanca. The tropical mountain range hosts one of the main concentrations of proglacial lakes in high-mountain settings worldwide, which have formed as a result of the dominant trend of modern glacier retreat. In the 20th century, glacial lake outbursts have severely affected large settlement areas in the Rio Santa Basin. Additionally to the striking newly emerged lakes, geomorphological evidence of paleolakes is found throughout the middle and lower valley sections. Based on empirical data from field research in over 20 valleys and the analysis of air and satellite images, the study provides a genetic classification of major lake types and a generalized model for the distribution of the present lakes and paleolakes. The origin of the lakes and their recurrent distribution pattern are associated with the individual stages of the Pleistocene to modern glaciation and their corresponding geomorphological landforms. Apart from the individual lake, the focus is put on the spatial arrangement of the lakes to each other based on a holistic landscape assessment. Implications are drawn for the hazard potential, in particular in terms of outburst cascades involving two or more lakes. On a supraregional scale, a clustering of certain lake types occurs in different mountain ranges of the Andes according to their specific topographical and glaciological settings. Even though the glaciated areas have all been subject to major ice losses, only some mountain regions are prone to form moraine-dammed lakes such as in the Cordillera Blanca. The key controlling factors for their formation are highlighted from a glacial-geomorphological point of view. The distribution of principal types of glacial lakes is outlined in a N–S profile along the Andes.

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Iturrizaga, Lasafam. "Glacial landform assemblages and pedestal moraines in the Cordillera Blanca (Peru)." Geomorphology 318 (October 2018): 283–302. http://dx.doi.org/10.1016/j.geomorph.2018.06.012.

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6

Klimeš, Jan. "Geomorphology and natural hazards of the selected glacial valleys, Cordillera Blanca, Peru." AUC GEOGRAPHICA 47, no. 2 (September 26, 2017): 25–31. http://dx.doi.org/10.14712/23361980.2015.14.

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7

Silverio, Walter, and Jean-Michel Jaquet. "Glacial cover mapping (1987–1996) of the Cordillera Blanca (Peru) using satellite imagery." Remote Sensing of Environment 95, no. 3 (April 2005): 342–50. http://dx.doi.org/10.1016/j.rse.2004.12.012.

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8

Emmer, A., and V. Vilímek. "New method for assessing the potential hazardousness of glacial lakes in the Cordillera Blanca, Peru." Hydrology and Earth System Sciences Discussions 11, no. 2 (February 26, 2014): 2391–439. http://dx.doi.org/10.5194/hessd-11-2391-2014.

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Abstract. This paper presents a new and easily repeatable objective method for assessing the potential hazardousness of glacial lakes within the Peruvian region of Cordillera Blanca (excluding ice-dammed lakes, which do not reach significant volumes in this region). The presented method was designed to meet four basic principles, which we considered as being crucial. These are: (a) principle of regional focus; (b) principle of objectivity; (c) principle of repeatability; and (d) principle of multiple results. Potential hazardousness is assessed based on a combination of decision trees for clarity and numerical calculation for objectivity. A total of seventeen assessed characteristics are used, of which seven have yet to be used in this context before. Also, several ratios and calculations are defined for the first time. We assume that it is not relevant to represent the overall potential hazardousness of a particular lake by one result (number), thus the potential hazardousness is described in the presented method by five separate results (representing five different glacial lake outburst flood scenarios). These are potentials for: (a) dam overtopping resulting from a dynamic slope movement into the lake; (b) dam overtopping following the flood wave originating in a lake situated upstream; (c) dam failure resulting from a dynamic slope movement into the lake; (d) dam failure following the flood wave originating in a lake situated upstream; and (e) dam failure following a heavy earthquake. All of these potentials theoretically range from 0 to 1. The presented method was verified on the basis of assessing the pre-flood conditions of seven lakes which have produced ten glacial lake outburst floods in the past and ten lakes which have not. A comparison of these results showed that the presented method successfully identifies the potentially hazardous lakes.

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Klimeš, Jan, Vít Vilímek, and Miroslava Benešová. "Landslide and glacial lake outburst flood hazard in the Chucchún River basin, Cordillera Blanca, Peru." AUC GEOGRAPHICA 50, no. 2 (November 30, 2015): 173–80. http://dx.doi.org/10.14712/23361980.2015.96.

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10

Stansell, Nathan D., Joseph M. Licciardi, Donald T. Rodbell, and Bryan G. Mark. "Tropical ocean-atmospheric forcing of Late Glacial and Holocene glacier fluctuations in the Cordillera Blanca, Peru." Geophysical Research Letters 44, no. 9 (May 8, 2017): 4176–85. http://dx.doi.org/10.1002/2016gl072408.

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Emmer, A., and V. Vilímek. "New method for assessing the susceptibility of glacial lakes to outburst floods in the Cordillera Blanca, Peru." Hydrology and Earth System Sciences 18, no. 9 (September 9, 2014): 3461–79. http://dx.doi.org/10.5194/hess-18-3461-2014.

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Abstract. This paper presents a new and easily repeatable method for assessing the susceptibility of glacial lakes to outburst floods (GLOFs) within the Peruvian region of the Cordillera Blanca. The presented method was designed to: (a) be repeatable (from the point of view of the demands on input data), (b) be reproducible (to provide an instructive guide for different assessors), (c) provide multiple results for different GLOF scenarios and (d) be regionally focused on the lakes of the Cordillera Blanca. Based on the input data gained from remotely sensed images and digital terrain models/topographical maps, the susceptibility of glacial lakes to outburst floods is assessed using a combination of decision trees for clarity and numerical calculation for repeatability and reproducibility. A total of seventeen assessed characteristics are used, of which seven have not been used in this context before. Also, several ratios and calculations are defined for the first time. We assume that it is not relevant to represent the overall susceptibility of a particular lake to outburst floods by one result (number), thus it is described in the presented method by five separate results (representing five different GLOF scenarios). These are potentials for (a) dam overtopping resulting from a fast slope movement into the lake, (b) dam overtopping following the flood wave originating in a lake situated upstream, (c) dam failure resulting from a fast slope movement into the lake, (d) dam failure following the flood wave originating in a lake situated upstream and (e) dam failure following a strong earthquake. All of these potentials include two or three components and theoretically range from 0 to 1. The presented method was verified on the basis of assessing the pre-flood conditions of seven lakes which have produced ten glacial lake outburst floods in the past and ten lakes which have not. A comparison of these results showed that the presented method successfully identified lakes susceptible to outburst floods (pre-flood conditions of lakes which have already produced GLOFs).

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Baťka, Jan, Vít Vilímek, Eva Štefanová, Simon J. Cook, and Adam Emmer. "Glacial Lake Outburst Floods (GLOFs) in the Cordillera Huayhuash, Peru: Historic Events and Current Susceptibility." Water 12, no. 10 (September 23, 2020): 2664. http://dx.doi.org/10.3390/w12102664.

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The aim of this paper is to create a glacial lake inventory for the Cordillera Huayhuash in Peru and to evaluate the susceptibility of lakes to the generation of glacial lake outburst floods (GLOFs). Using high-resolution satellite images, we undertook qualitative and quantitative analysis of lake type, characteristics and distribution, and placed our findings within the context of existing Peru-wide lake inventories. We also mapped and analyzed past GLOFs, revealing a total of 10 GLOFs and 4 ambiguous events, most of which have not been reported before. We found that past GLOFs usually occurred as a result of moraine dam breach during the proglacial stage of lake evolution. Further, we used our lake inventory to evaluate GLOF susceptibility of all lakes larger than 20,000 m2. Of 46 evaluated lakes, only two lakes (Lake Tsacra and Lake W014) are currently susceptible to generating a GLOF, which would most likely be through dam overtopping resulting from a flood originating in smaller lakes located upstream. The future perspectives of lake evolution and implications for GLOF hazard management are discussed in light of the post-Little Ice Age glacier ice loss as well as in the context of extensive related research undertaken in the nearby Cordillera Blanca.

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Emmer, A., and V. Vilímek. "Review Article: Lake and breach hazard assessment for moraine-dammed lakes: an example from the Cordillera Blanca (Peru)." Natural Hazards and Earth System Sciences 13, no. 6 (June 18, 2013): 1551–65. http://dx.doi.org/10.5194/nhess-13-1551-2013.

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Abstract. Glacial lake outburst floods (GLOFs) and related debris flows represent a significant threat in high mountainous areas across the globe. It is necessary to quantify this threat so as to mitigate their catastrophic effects. Complete GLOF hazard assessment incorporates two phases: the probability of water release from a given glacial lake is estimated through lake and breach hazard assessment while the endangered areas are identified during downstream hazard assessment. This paper outlines a number of methods of lake and breach hazard assessment, which can be grouped into three categories: qualitative, of which we outline eight; semi-quantitative, of which we outline two; and quantitative, of which we outline three. It is considered that five groups of critical parameters are essential for an accurate regionally focused hazard assessment method for moraine-dammed lakes in the Cordillera Blanca. These comprise the possibility of dynamic slope movements into the lake, the possibility of a flood wave from a lake situated upstream, the possibility of dam rupture following a large earthquake, the size of the dam freeboard (or ratio of dam freeboard), and a distinction between natural dams and those with remedial work. It is shown that none of the summarised methods uses all these criteria with, at most, three of the five considered by the outlined methods. A number of these methods were used on six selected moraine-dammed lakes in the Cordillera Blanca: lakes Quitacocha, Checquiacocha, Palcacocha, Llaca, Rajucolta, and Tararhua. The results have been compared and show that each method has certain advantages and disadvantages when used in this region. These methods demonstrate that the most hazardous lake is Lake Palcacocha.

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Muñoz, Randy, Christian Huggel, Holger Frey, Alejo Cochachin, and Wilfried Haeberli. "Glacial lake depth and volume estimation based on a large bathymetric dataset from the Cordillera Blanca, Peru." Earth Surface Processes and Landforms 45, no. 7 (February 27, 2020): 1510–27. http://dx.doi.org/10.1002/esp.4826.

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Emmer, A., V. Vilímek, and M. L. Zapata. "Hazard mitigation of glacial lake outburst floods in the Cordillera Blanca (Peru): the effectiveness of remedial works." Journal of Flood Risk Management 11 (April 8, 2016): S489—S501. http://dx.doi.org/10.1111/jfr3.12241.

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Klimeš, J., J. Novotný, I. Novotná, B. Jordán de Urries, V. Vilímek, A. Emmer, T. Strozzi, et al. "Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru)." Landslides 13, no. 6 (July 15, 2016): 1461–77. http://dx.doi.org/10.1007/s10346-016-0724-4.

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Reynolds, J. M., A. Dolecki, and C. Portocarrero. "The construction of a drainage tunnel as part of glacial lake hazard mitigation at Hualcán, Cordillera Blanca, Peru." Geological Society, London, Engineering Geology Special Publications 15, no. 1 (1998): 41–48. http://dx.doi.org/10.1144/gsl.eng.1998.015.01.05.

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Magnússon, Rúna, Erik Cammeraat, Andreas Lücke, Boris Jansen, Anaïs Zimmer, and Jorge Recharte. "Influence of glacial sediments on the chemical quality of surface water in the Ulta valley, Cordillera Blanca, Peru." Journal of Hydrology 587 (August 2020): 125027. http://dx.doi.org/10.1016/j.jhydrol.2020.125027.

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Wigmore, Oliver, and Bryan Mark. "Monitoring tropical debris-covered glacier dynamics from high-resolution unmanned aerial vehicle photogrammetry, Cordillera Blanca, Peru." Cryosphere 11, no. 6 (November 3, 2017): 2463–80. http://dx.doi.org/10.5194/tc-11-2463-2017.

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Abstract. The glaciers of the Cordillera Blanca, Peru, are rapidly retreating and thinning as a result of climate change, altering the timing, quantity and quality of water available to downstream users. Furthermore, increases in the number and size of proglacial lakes associated with these melting glaciers is increasing potential exposure to glacier lake outburst floods (GLOFs). Understanding how these glaciers are changing and their connection to proglacial lake systems is thus of critical importance. Most satellite data are too coarse for studying small mountain glaciers and are often affected by cloud cover, while traditional airborne photogrammetry and lidar are costly. Recent developments have made unmanned aerial vehicles (UAVs) a viable and potentially transformative method for studying glacier change at high spatial resolution, on demand and at relatively low cost.Using a custom designed hexacopter built for high-altitude (4000–6000 m a. s. l. ) operation, we completed repeat aerial surveys (2014 and 2015) of the debris-covered Llaca Glacier tongue and proglacial lake system. High-resolution orthomosaics (5 cm) and digital elevation models (DEMs) (10 cm) were produced and their accuracy assessed. Analysis of these datasets reveals highly heterogeneous patterns of glacier change. The most rapid areas of ice loss were associated with exposed ice cliffs and meltwater ponds on the glacier surface. Considerable subsidence and low surface velocities were also measured on the sediments within the pro-glacial lake, indicating the presence of extensive regions of buried ice and continued connection to the glacier tongue. Only limited horizontal retreat of the glacier tongue was observed, indicating that measurements of changes in aerial extent alone are inadequate for monitoring changes in glacier ice quantity.

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Davis, Mary E., and Lonnie G. Thompson. "An Andean ice-core record of a Middle Holocene mega-drought in North Africa and Asia." Annals of Glaciology 43 (2006): 34–41. http://dx.doi.org/10.3189/172756406781812456.

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AbstractAn ice core from the Nevado Huascaran col in the Cordillera Blanca of northern Peru contains high-resolution time series of dust concentrations and size distributions since the end of the last glacial stage. A large dust peak, dated ∼4500 years ago, is contemporaneous with a widespread and prolonged drought that apparently extended from North Africa to eastern China, evidence of which occurs in historical, archeological and paleoclimatic records. This event may have been associated with several centuries of weak Asian/Indian/African monsoons, possibly linked with a protracted cooling in the North Atlantic. During the second half of the 20th century, high austral-summer dust concentrations in the Huascaran record are significantly correlated with atmospheric conditions, such as sea-level pressure and zonal wind velocities that are consistent with El Nino-Southern Oscillation (ENSO) and positive North Atlantic Oscillation (NAO) indices, and with aridity in North Africa, southwest Asia and the Middle East. Therefore, the dominant submicron fraction of the dust may have been transported by more intense northeasterly trade winds from the African dry regions across the tropical Atlantic during a period of frequent and/or intense ENSO activity. The proposed ENSO conditions that may have been linked with drought in the monsoon region may also have contributed to aridity in tropical South America, including the Cordillera Blanca.

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Margirier, Audrey, Jean Braun, Xavier Robert, and Laurence Audin. "Role of erosion and isostasy in the Cordillera Blanca uplift: Insights from landscape evolution modeling (northern Peru, Andes)." Tectonophysics 728-729 (March 2018): 119–29. http://dx.doi.org/10.1016/j.tecto.2018.02.009.

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Emmer, Adam, Stephan Harrison, Martin Mergili, Simon Allen, Holger Frey, and Christian Huggel. "70 years of lake evolution and glacial lake outburst floods in the Cordillera Blanca (Peru) and implications for the future." Geomorphology 365 (September 2020): 107178. http://dx.doi.org/10.1016/j.geomorph.2020.107178.

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Rodbell, Donald T. "Subdivision of Late Pleistocene Moraines in the Cordillera Blanca, Peru, Based on Rock-Weathering Features, Soils, and Radiocarbon Dates." Quaternary Research 39, no. 2 (March 1993): 133–43. http://dx.doi.org/10.1006/qres.1993.1017.

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AbstractThe progressive development of unusual rock-weathering features and soils and minimum-limiting radiocarbon dates provide a basis for subdividing four groups of late Pleistocene moraines on the west side of the Cordillera Blanca, northern Peru (9°20′1°000′S, 77°10′-77°30′W). Boulders on the youngest late Pleistocene moraines have 10 to 14-cm-tall weathering posts; soils on these moraines yield mean profile development index (PDI) values of 0.05 ± 0.04 (±1σ). These moraines date between ca. 13,500 and 9700 ± 500 yr B.P., older than previously postulated. The next older moraines have boulders with weathering-post heights between 20 and 25 cm and soils with PDI values of 0.08 ± 0.07, and were deposited prior to 13,280 ± 190 yr B.P., probably during the last glacial maximum (marine isotope stage 2). Moraines from an older glaciation have boulders with weathering posts between 39 and 50 cm high, soils that yield PDI values of 0.21 ± 0.07, and are older than 19,700 ± 340 yr B.P. Boulders on moraines from a still older glaciation have lost ca. 50% of their above-ground volume, and have weathering posts between 62 and 70 cm high. PDI values for soils on these moraines are 0.32 ± 0.06. Linear and logarithmic models of weathering-post and soil development with time are used to estimate minimum and maximum ages for the two oldest moraine groups. Linear models suggest that the second oldest moraines are between ca. 20,500 and 46,500 yr B.P., and that the oldest moraines are between ca. 29,000 and 72,000 yr B.P. In contrast, logarithmic models suggest ages of greater than ca. 75,500 yr B.P. and greater than ca. 500,000 yr B.P., respectively.

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AUBRY-WAKE, CAROLINE, DORIAN ZÉPHIR, MICHEL BARAER, JEFFREY M. McKENZIE, and BRYAN G. MARK. "Importance of longwave emissions from adjacent terrain on patterns of tropical glacier melt and recession." Journal of Glaciology 64, no. 243 (December 26, 2017): 49–60. http://dx.doi.org/10.1017/jog.2017.85.

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ABSTRACTTropical glaciers constitute an important source of water for downstream populations. However, our understanding of glacial melt processes is still limited. One observed process that has not yet been quantified for tropical glaciers is the enhanced melt caused by the longwave emission transfer. Here, we use high-resolution surface temperatures obtained from the thermal infrared imagery of the Cuchillacocha Glacier, in the Cordillera Blanca, Peru in June 2014 to calculate a margin longwave flux. This longwave flux, reaching the glacier margin from the adjacent exposed rock, varies between 81 and 120 W m−2 daily. This flux is incorporated into a physically-based melt model to assess the net radiation budget at the modeled glacier margin. The simulation results show an increase in the energy available for melt by an average of 106 W m−2 during the day when compared with the simulation where the LWmargin flux is not accounted for. This value represents an increase in ablation of ~1.7 m at the glacier margin for the duration of the dry season. This study suggests that including the quantification of the glacier margin longwave flux in physically-based melt models results in an improved assessment of tropical glacier energy budget and meltwater generation.

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Klimeš, Jan, Miroslava Benešová, Vít Vilímek, Petr Bouška, and Alejo Cochachin Rapre. "The reconstruction of a glacial lake outburst flood using HEC-RAS and its significance for future hazard assessments: an example from Lake 513 in the Cordillera Blanca, Peru." Natural Hazards 71, no. 3 (December 7, 2013): 1617–38. http://dx.doi.org/10.1007/s11069-013-0968-4.

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Sevillano-Ríos, C. Steven, and Amanda D. Rodewald. "Avian community structure and habitat use ofPolylepisforests along an elevation gradient." PeerJ 5 (April 27, 2017): e3220. http://dx.doi.org/10.7717/peerj.3220.

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BackgroundAs one of the highest forest ecosystems in the world,Polylepisforests are recognized both as center of endemism and diversity along the Andes and as an ecosystem under serious threat from habitat loss, fragmentation, and climate change due to human activities. Effective conservation efforts are limited, in part, by our poor understanding of the ecology and habitat needs of the ecosystem’s flora and fauna.MethodsIn 2014–2015, we studied bird communities and 19 associated local and landscape attributes within five forested glacial valleys within the Cordillera Blanca and Huascaran National Park, Peru. We surveyed birds during the dry (May–August) and wet (January–April) seasons at 130 points distributed along an elevational gradient (3,300–4,700 m) and analyzed our data using Canonical Correspondence Analysis (CCA).ResultsWe associated a total of 50 species of birds, including 13 species of high conservation concern, with four basic habitat types: (1)Polylepis sericeaforests at low elevations, (2)P. weberbaueriforests at high elevations, (3) Puna grassland and (4) shrublands. Four species of conservation priority (e.g., Microspingus alticola) were strongly associated with large forest patches (∼10-ha) ofP. sericeaat lower elevations (<3,800 m), whereas another four (e.g., Anairetes alpinus) were associated with less disturbed forests ofP. weberbaueriat higher elevations (>4,200 m).DiscussionResults suggest two key strategies form the cornerstones of conservation efforts: (a) protect large remnant (>10-ha)P. sericeaforests at lower elevations and (b) maintain all relicts ofP. weberbaueri, irrespective of size, at high elevations (>4,200 m).

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Frey, Holger, Christian Huggel, Rachel E. Chisolm, Patrick Baer, Brian McArdell, Alejo Cochachin, and César Portocarrero. "Multi-Source Glacial Lake Outburst Flood Hazard Assessment and Mapping for Huaraz, Cordillera Blanca, Peru." Frontiers in Earth Science 6 (November 21, 2018). http://dx.doi.org/10.3389/feart.2018.00210.

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