scholarly journals Glaciers, glacial lakes and glacial lake outburst floods in the Mount Everest region, Nepal

2009 ◽  
Vol 50 (53) ◽  
pp. 81-86 ◽  
Author(s):  
Samjwal Ratna Bajracharya ◽  
Pradeep Mool
Keyword(s):  
Average Rate ◽  
Glacial Lake ◽  
High Mountain ◽  
Glacial Lakes ◽  
Mount Everest ◽  
The Past ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Himalayan Glaciers ◽  
Recent Climate

AbstractRecent climate changes have had a significant impact on the high-mountain glacial environment. Rapid melting of glaciers has resulted in the formation and expansion of moraine-dammed lakes, creating a potential danger from glacial lake outburst floods (GLOFs). Most lakes have formed during the second half of the 20th century. Glaciers in the Mount Everest (Sagamartha) region, Nepal, are retreating at an average rate of 10–59 ma–1. From 1976 to 2000, Lumding and Imja Glaciers retreated 42 and 34 ma–1, respectively, a rate that increased to 74 ma–1 for both glaciers from 2000 to 2007. During the past decade, Himalayan glaciers have generally been shrinking and retreating faster while moraine-dammed lakes have been proliferating. Although the number of lakes above 3500 m a.s.l. has decreased, the overall area of moraine-dammed lakes is increasing. Understanding the behaviour of glaciers and glacial lakes is a vital aspect of GLOF disaster management.

scholarly journals Simulation and Assessment of Future Glacial Lake Outburst Floods in the Poiqu River Basin, Central Himalayas

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1376
Author(s):  
Taigang Zhang ◽  
Weicai Wang ◽  
Tanguang Gao ◽  
Baosheng An
Keyword(s):  
River Basin ◽  
Hazard Assessment ◽  
Glacial Lake ◽  
High Mountain ◽  
Glacial Lakes ◽  
Central Himalayas ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Social And Economic Development ◽  
Glacial Lake Outburst Flood

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.

scholarly journals Glacial Lakes in the Nepal Himalaya: Inventory and Decadal Dynamics (1977–2017)

2018 ◽  
Vol 10 (12) ◽  
pp. 1913 ◽  
Author(s):  
Nitesh Khadka ◽  
Guoqing Zhang ◽  
Sudeep Thakuri
Keyword(s):  
Glacial Lake ◽  
Central Himalaya ◽  
Glacial Lakes ◽  
Nepal Himalaya ◽  
Surface Areas ◽  
Proglacial Lakes ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Himalayan Glaciers ◽  
Lake Dynamics

Himalayan glaciers, in general, are shrinking and glacial lakes are evolving and growing rapidly in number and size as a result of climate change. This study presents the latest remote sensing-based inventory (2017) of glacial lakes (size ≥0.0036 km2) across the Nepal Himalaya using optical satellite data. Furthermore, this study traces the decadal glacial lake dynamics from 1977 to 2017 in the Nepal Himalaya. The decadal mapping of glacial lakes (both glacial-fed and nonglacial-fed) across the Nepal Himalaya reveals an increase in the number and area of lakes from 1977 to 2017, with 606 (55.53 ± 16.52 km2), 1137 (64.56 ± 11.64 km2), 1228 (68.87 ± 12.18 km2), 1489 (74.2 ± 14.22 km2), and 1541 (80.95 ± 15.25 km2) glacial lakes being mapped in 1977, 1987, 1997, 2007, and 2017, respectively. Glacial lakes show heterogeneous rates of expansion in different river basins and elevation zones of Nepal, with apparent decadal emergences and disappearances. Overall, the glacial lakes exhibited ~25% expansion of surface areas from 1987 to 2017. For the period from 1987 to 2017, proglacial lakes with ice contact, among others, exhibited the highest incremental changes in terms of number (181%) and surface area (82%). The continuous amplified mass loss of glaciers, as reported in Central Himalaya, is expected to accompany glacial lake expansion in the future, increasing the risk of glacial lake outburst floods (GLOFs). We emphasize that the rapidly increasing glacial lakes in the Nepal Himalaya can pose potential GLOF threats to downstream population and infrastructure.

What’s in a lake? Glacial Lake Outburst Floods in the Peruvian Andes.

2021 ◽  
Author(s):  
Joanne Wood ◽  
Stephan Harrison ◽  
Ryan Wilson ◽  
Neil Glasser ◽  
John Reynolds ◽  
...  
Keyword(s):  
Climate Change ◽  
Glacial Lake ◽  
Peruvian Andes ◽  
The Past ◽  
The Andes ◽  
Glacier Recession ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Lake Systems ◽  
Physical Components

<p>Climate change is resulting in mass loss and the retreat of glaciers in the Andes, exposing steep valley sides, over-deepened valley bottoms, and creating glacial lakes behind moraine dams. Glacial Lake Outburst Floods (GLOFs) present the biggest risk posed by glacier recession in Peru. Understanding the characteristics of lakes that have failed in the past will provide an aid to identifying those lakes that might fail in the future and narrow down which lakes are of greatest interest for reducing the risks to local vulnerable populations. </p><p>Using a newly created lake inventory for the Peruvian Andes (Wood et al., in review) and a comprehensive GLOF inventory (unpublished) we investigate lakes from which GLOFs have occurred in the past. This is to establish which physical components of the glacial lake systems are common to those lakes that have failed previously and which can be identified remotely, easily and objectively, in order to improve existing methods of hazard assessment.</p>

scholarly journals Reconstructing the History of Glacial Lake Outburst Floods (GLOF) in the Kanchenjunga Conservation Area, East Nepal: An Interdisciplinary Approach

2020 ◽  
Vol 12 (13) ◽  
pp. 5407
Author(s):  
Alton C. Byers ◽  
Mohan Bahadur Chand ◽  
Jonathan Lala ◽  
Milan Shrestha ◽  
Elizabeth A. Byers ◽  
...  
Keyword(s):  
Interdisciplinary Approach ◽  
Debris Avalanche ◽  
Field Investigation ◽  
Glacial Lake ◽  
High Mountain ◽  
Lateral Moraine ◽  
Conservation Area ◽  
Terminal Moraine ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods

An interdisciplinary field investigation of historic glacial lake outburst floods (GLOFs) in the Kanchenjunga region of Nepal was conducted between April and May, 2019. Oral history and field measurements suggested that at least six major GLOFs have occurred in the region since 1921. A remote sensing analysis confirmed the occurrence of the six GLOFs mentioned by informants, including two smaller flood events not mentioned that had occurred at some point before 1962. A numerical simulation of the Nangama GLOF suggested that it was triggered by an ice/debris avalanche of some 800,000 m3 of material, causing a surge wave that breached the terminal moraine and released an estimated 11.2 × 106 m3 ± 1.4 × 106 m3 of water. Debris from the flood dammed the Pabuk Khola river 2 km below the lake to form what is today known as Chheche Pokhari lake. Some concern has been expressed for the possibility of a second GLOF from Nangama as the result of continued and growing landslide activity from its right lateral moraine. Regular monitoring of all lakes and glaciers is recommended to avoid and/or mitigate the occurrence of future GLOF events in the region. Collectively, the paper demonstrates the benefits and utility of interdisciplinary research approaches to achieving a better understanding of past and poorly documented GLOF events in remote, data-scarce high mountain environments.

Identifying key predictors for the susceptibility of Himalayan glacial lakes to sudden outburst floods

2020 ◽  
Author(s):  
Melanie Fischer ◽  
Georg Veh ◽  
Oliver Korup ◽  
Ariane Walz
Keyword(s):  
Logistic Regression ◽  
Binary Logistic Regression ◽  
Glacial Lake ◽  
Occurrence Rate ◽  
Past Century ◽  
Glacial Lakes ◽  
Mountain Areas ◽  
Logistic Regression Models ◽  
The Past ◽  
Outburst Floods

<p>Despite being a rather rare phenomenon when compared to the occurrence rates of other alpine hazards (e.g. landslides, avalanches), glacial lake outburst floods (GLOFs) pose a significant threat to downvalley communities in glaciated mountain areas. Characteristically high peak discharge rates and flood volumes, documented to have reached 30,000 m³/s and > 50 million m³ in the past century, not only provide GLOFs with a landscape-forming potential but also killed a reported global total of > 12,000 people and caused severe damage to infrastructures. Extensive glacial covers and steep topographic gradients, coupled with rapidly changing socio-economical implications, make the Hindu-Kush-Himalaya (HKH) a high priority region for GLOF research, even though recent studies suggest an annual occurrence rate of 1.3 GLOFs per year across this range during the past three decades. So far, GLOF research in the greater HKH region has been predominantly focused on the classification of potentially dangerous glacial lakes derived from analysing a limited number of glacial lakes and even fewer reportedly GLOF-generating glacial lakes. Moreover, subjectively set thresholds are commonly used to produce GLOF hazard classification matrices. Contrastingly, our study is aimed at an unbiased, statistical robust and reproducible assessment of GLOF susceptibility. It is based on the currently most complete inventory of GLOFs in the HKH since the 1980’s, which comprises 38 events. In order to identify key predictors for GLOF susceptibility, a total of 104 potential predictors are tested in logistic regression models. These parameters cover four predictor categories, which describe each glacial lake’s a) topography, b) catchment glaciers, c) geology and seismicity in its surroundings, and c) local climatic variables. Both classical binary logistic regression as well as hierarchical logistic regression approaches are implemented in order to assess which factors drive susceptibility of HKH glacial lakes to sudden outbursts and whether these are regionally distinct.</p>

scholarly journals Climate change and the global pattern of moraine-dammed glacial lake outburst floods

2017 ◽  
Author(s):  
Stephan Harrison ◽  
Jeffrey S. Kargel ◽  
Christian Huggel ◽  
John Reynolds ◽  
Dan H. Shugar ◽  
...  
Keyword(s):  
Climate Change ◽  
Ice Age ◽  
Dam Failure ◽  
Glacial Lake ◽  
Glacier Recession ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Lake Formation ◽  
Recent Climate ◽  
Moraine Dam Failure

Abstract. Despite recent research identifying a clear anthropogenic impact on glacier recession, the effect of recent climate change on glacier-related hazards is at present unclear. Here we present the first global spatio-temporal assessment of glacial lake outburst floods (GLOFs) focusing explicitly on lake drainage following moraine dam failure. These floods occur as mountain glaciers recede and downwaste and many have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the collapse of moraine-dammed lakes provides insights into the historical trends of GLOFs and their distributions under current and future global climate change. We observe a clear global increase in GLOF frequency and their regularity around 1930, which likely represents a lagged response to post-Little Ice Age warming. Notably, we also show that GLOF frequency and their regularity – rather unexpectedly – has declined in recent decades even during a time of rapid glacier recession. Although previous studies have suggested that GLOFs will increase in response to climate warming and glacier recession, our global results demonstrate that this has not yet clearly happened. From assessment of the timing of climate forcing, lag times in glacier recession, lake formation and moraine dam failure, we predict increased GLOF frequencies during the next decades and into the 22nd century.

scholarly journals New method for assessing the potential hazardousness of glacial lakes in the Cordillera Blanca, Peru

2014 ◽  
Vol 11 (2) ◽  
pp. 2391-2439 ◽  
Author(s):  
A. Emmer ◽  
V. Vilímek
Keyword(s):  
Slope Movement ◽  
Dam Failure ◽  
Glacial Lake ◽  
Flood Wave ◽  
Glacial Lakes ◽  
Cordillera Blanca ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Glacial Lake Outburst Flood ◽  
Dam Overtopping

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.

scholarly journals Glacial Lake Changes and Identification of Potentially Dangerous Glacial Lakes in the Yi’ong Zangbo River Basin

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 538
Author(s):  
Hongyu Duan ◽  
Xiaojun Yao ◽  
Dahong Zhang ◽  
Miaomiao Qi ◽  
Juan Liu
Keyword(s):  
River Basin ◽  
Glacial Lake ◽  
Glacial Lakes ◽  
Huge Number ◽  
First Order ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Glacier Melting ◽  
First Order Method ◽  
Very High

The southeastern Tibetan Plateau, where monsoonal temperate glaciers are most developed, has a huge number of glacial lakes. Based on Landsat Operational Land Imager (OLI) images, 192 glacial lakes with a total area of 45.73 ± 6.18 km2 in 2016 were delineated in the Yi’ong Zangbo River Basin. Glacial lakes with areas of less than 0.1 km2 accounted for 81.77% of the total number, and glacial lakes located above 4500 m elevation comprised 83.33%. Dramatic glacier melting caused by climate warming has occurred, resulting in the formation and expansion of glacial lakes and the increase of potential glacial lake outburst floods (GLOFs) risk. From 1970 to 2016, the total area of glaciers in the basin has decreased by 35.39%, whereas the number and total area of glacial lakes have, respectively, increased by 86 and 1.59 km2. In that time, 110 new glacial lakes emerged, whereas 24 of the original lakes disappeared. The newly formed lakes have a smaller mean area but higher mean elevation than the lakes that disappeared. Based on five indicators, a first-order method was used to identify glacial lakes that pose potential threats. We identified 10 lakes with very high, 7 with high, 31 with medium, and 19 with low GLOF susceptibility, out of 67 moraine-dammed glacial lakes with areas larger than 0.02 km2. Understanding the behavior of glaciers and glacial lakes is a vital aspect of GLOFs disaster management, and the monitoring of glacial lakes should be strengthened.

Glacial Lake Outburst Floods Early Warning System to save lives and livelihood of the Nepal Himalaya communities: A case Study of Imja Glacial Lake, Nepal 

2021 ◽  
Author(s):  
Deepak Kc ◽  
Top Khatri ◽  
Rishiram Sharma
Keyword(s):  
Climate Change ◽  
Risk Reduction ◽  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Glacial Lake ◽  
Glacial Lakes ◽  
Community Based ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods

<p>Nepal, a mountainous country, is experiencing multiple disasters, majority of which are induced by Climate Change. Erratic rainfall, extremely high temperature during summer, cold waves are some of them. Nepal will experience the impacts of climate change through an increase in temperature, more frequent heat waves and shorter frost durations in the future (5AR IPCC). Nepal is witnessing the increased maximum temperature of 0.56<sup>o</sup>C per decade and the increment of the temperature is even higher in the mountain region (ICIMOD 2019). One of the major impacts of Climate Change among others, is glacier retreat and Glacial Lake Outburst Floods (GLOFS). Nepal has already experienced more than 26 GLOFS (UNDP and ICIMOD 2020), originated both from Nepal and China, Tibet.</p><p>The Imja Glacial Lake is located at 27° 53′ 55“ N latitude, 86° 55’ 20” E longitude and at an altitude of 5010 m in Everest Region of Nepal Himalayas.  Imja was identified during 1960s as a small supra lake, was later expanded to an area of <strong>1.28 Km<sup>2</sup></strong>, <strong>148.9 meter deep</strong>, holding <strong>75.2 million cubic meters </strong>of water in 2014.   Lake lowering by 3.4 metres and establishment of early warning system was done in 2016 by the Government of Nepal and UNDP with the support of Global Environment Facility.  Hydro-met stations & GLOF Sensors in the periphery and downstream  of Imja Lake and automated early warning sirens in six prime settlements in the  downstream of Imja  watershed  linking with  dynamic SMS Alert system along 50 km downstream of Imja Dudh Koshi River have been have been linked with community-based DRM institutions at local government level. This initiative is important for preparedness and response of GLOF Risk Reduction in the Imja Valley, benefitting 71,752 vulnerable people, both local and the tourists visiting the Everest Region of Nepal.</p><p>Early Warning System of Tsho Rolpa Glacial Lake, the biggest Glacial Lake of Nepal is another example in the such system. New inventory of Glacial Lakes has identified 47 critical lakes as priority lakes for GLOF Risk Reduction in Koshi, Gandaki and Karnali basins. In the new context of federal  governance system, the role of federal, province and local government and communities is crucial  for achieving the targets of  Sendai Framework for Disaster Risk Reduction , particularly target “g” and SDGs 11 and 13  through integrating  the targets in the regular planning and   its’ implementation for resilient and Sustainable Development of  Nepal.</p><p><strong>References:</strong></p><p>Glacial lakes and glacial lake outburst floods in Nepal. Kathmandu, ICIMOD 2011,  Nepal Disaster Report, Ministry of Home affairs (MoHA) , 2015, 2018 Annual Reports UNDP 2016, 2017 and 2018,  Imja Hydro-Meteorological and Early Warning System User Manual, Government of Nepal and UNDP, 2017 Project Completion Report: Community Based Flood and Glacial Lake Outburst Risk Reduction Project, Government of Nepal and UNDP, 2017,  Inventory of glacial lakes and identification of potentially dangerous glacial lakes in the Koshi, Gandaki, and Karnali River Basins of Nepal, the Tibet Autonomous Region of China, and India. Research Report, ICIMOD and UNDP, 2020</p><p> </p>

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