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

Author(s):  
Joanne Wood ◽  
Stephan Harrison ◽  
Ryan Wilson ◽  
Neil Glasser ◽  
John Reynolds ◽  
...  

<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a newly created lake inventory for the Peruvian Andes (Wood et al., in review) and a comprehensive GLOF inventory (unpublished) we investigate lakes from which GLOFs have occurred in the past.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>

2017 ◽  
Author(s):  
Stephan Harrison ◽  
Jeffrey S. Kargel ◽  
Christian Huggel ◽  
John Reynolds ◽  
Dan H. Shugar ◽  
...  

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.


2018 ◽  
Vol 12 (4) ◽  
pp. 1195-1209 ◽  
Author(s):  
Stephan Harrison ◽  
Jeffrey S. Kargel ◽  
Christian Huggel ◽  
John Reynolds ◽  
Dan H. Shugar ◽  
...  

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. GLOFs can have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the rapid drainage 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 regularity – rather unexpectedly – have 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 an 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.


2021 ◽  
Author(s):  
Deepak Kc ◽  
Top Khatri ◽  
Rishiram Sharma

<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>


Author(s):  
Somana Riaz ◽  
Arshad Ali ◽  
Muhammad N. Baig

The greater Himalayan Mountains host the largest snow covered area outside the polar regions and serves as the source for some of the major fluvial systems of the world. The region acts as the lifeline for approximately 10% of the world’s population. The terrain is geologically active, highly susceptible to climate change processes and plays a significant role in global hydro-meteorological cycles and biodiversity. With the increasing impacts of climate change to the glaciers and ice caps during the past few decades, people living in the Himalayas have become vulnerable to a higher risk of floods, avalanches and glacial lake outburst floods(GLOFs). This study reviewed the work carried out by earlier researchers to understand the history and science of GLOFs and their potential risk to the communities in the Himalayanbelt, particularly in Pakistan.


2017 ◽  
Author(s):  
Stephan Harrison ◽  
Jeffrey S. Kargel ◽  
Christian Huggel ◽  
John Reynolds ◽  
Dan H. Shugar ◽  
...  

Author(s):  
David J. A. Evans

A knowledge of glaciation is important because it provides us with an understanding of glaciers as Earth surface systems face climate change and of the glacial materials beneath the surface. Crucial are glacier-related hazards impacting directly on human society and glacial landforms and sediments lying at the surface of some of the most densely populated parts of our planet. ‘Glaciers, humans, and enduring ice’ considers glacial hazards, such as glacial lake outburst floods, and important engineering considerations, including sediment failure and seepage. It discusses the valuable legacy of past glaciations and asks if Earth is entering a new phase of ice-free conditions, the like of which it has not endured for more than 35 million years.


2009 ◽  
Vol 50 (53) ◽  
pp. 81-86 ◽  
Author(s):  
Samjwal Ratna Bajracharya ◽  
Pradeep Mool

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.


Hydrology ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 3
Author(s):  
Vitalii Zaginaev ◽  
Kristyna Falatkova ◽  
Bohumir Jansky ◽  
Miroslav Sobr ◽  
Sergey Erokhin

Debris flows caused by glacial lake outburst floods (GLOFs) are common hazards in mountain environments. The risk posed by glacial lake outburst hazards is particularly evaluated where the lower reaches of catchments are populated. A potentially dangerous lake has been identified adjacent to the Uchitel Glacier in Northern Tien Shan. This lake formed between 1988 and 1994 on the site of a retreated glacier in the upper part of the Aksay Valley. In this study we consider the possibility of an outburst of this pro-glacial lake in the future. The study involved bathymetry mapping of the lake, detailed profile sections of the valley, flow rate measurements on the Aksay river, and monitoring of the lake development using satellite images. Modelling of secondary debris flow inundation heights and hazard footprints has been undertaken. The outburst of this lake could cause powerful debris flows posing a threat to permanent residents living downstream, in the Ala-Archa Valley. Monitoring of the lake over the past ten years suggests certain changes in the runoff to the subsurface, and an increase in lake depth is observed. Glacial lakes with subsurface drainage are considered to be the most hazardous type as the knowledge of drainage channels functioning is still very limited and, thus, the timing of an outburst is hard to predict. Development of monitoring approaches to support forecasting of these hazards is of paramount importance to safety in mountain territories globally.


2019 ◽  
Vol 11 (9) ◽  
pp. 1082 ◽  
Author(s):  
Xiankun Yang ◽  
Xixi Lu ◽  
Edward Park ◽  
Paolo Tarolli

Lakes in the Hindu Kush-Himalaya-Tibetan (HKHT) regions are crucial indicators for the combined impacts of regional climate change and resultant glacier retreat. However, they lack long-term systematic monitoring and thus their responses to recent climatic change still remain only partially understood. This study investigated lake extent fluctuations in the HKHT regions over the past 40 years using Landsat (MSS/TM/ETM+/OLI) images obtained from the 1970s to 2014. Influenced by different regional atmospheric circulation systems, our results show that lake changing patterns are distinct from region to region, with the most intensive lake shrinking observed in northeastern HKHT (HKHT Interior, Tarim, Yellow, Yangtze), while the most extensive expansion was observed in the western and southwestern HKHT (Amu Darya, Ganges Indus and Brahmaputra), largely caused by the proliferation of small lakes in high-altitude regions during 1970s–1995. In the past 20 years, extensive lake expansions (~39.6% in area and ~119.1% in quantity) were observed in all HKHT regions. Climate change, especially precipitation change, is the major driving force to the changing dynamics of the lake fluctuations; however, effects from the glacier melting were also significant, which contributed approximately 31.9–40.5%, 16.5–39.3%, 12.8–29.0%, and 3.3–6.1% of runoff to lakes in the headwaters of the Tarim, Amu Darya, Indus, and Ganges, respectively. We consider that the findings in this paper could have both immediate and long-term implications for dealing with water-related hazards, controlling glacial lake outburst floods, and securing water resources in the HKHT regions, which contain the headwater sources for some of the largest rivers in Asia that sustain 1.3 billion people.


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