New Study Offers Window into Glacial Lake Outburst Floods

A recent geological study has shed some light on the cause of a major, yet elusive destructive natural hazard triggered by failed natural dams holding back glacial lakes. The findings show how previously unrecognized factors like thinning glacier ice and moisture levels in the ground surrounding a lake can determine the size and frequency of Glacier Lake Outburst Floods, or GLOFs.

Palcacocha Lake in 2008, showing its enclosing moraine; the 1941 breach is visible in the lower right (Source: Colette Simonds/The Glacial Lake Handbook).

The risks of these glacial floods are generally considered increasingly acute across the world, as warming atmospheric temperatures prompt ice and snow on mountain ranges to retreat and to swell glacial lakes.

Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru), published in  Landslides in July 2016, centers its study on Lake Palcacocha in the Cordillera Blanca mountain region of central Peru.  Since Palcacocha is one of almost 600 lakes in the Cordillera Blanca mountain range dammed by glacial moraines, the population of the region lives under serious threat of GLOFs.

The Landslides article is a step in understanding a previously understudied geological phenomenon.  As little as five years ago scientists acknowledged the lack of research on the subject.

“We don’t really have the scientific evidence of these slopes breaking off and moraine stability… but personal observations are suggesting there are a lot of those…” said Ph.D. environmental historian Mark Carey in a 2011 video where he describes GOLFs.

 

Glacial Lake Outburst Flood risks do not always emanate from mountain glacier meltwater that flows downstream. As this study shows,  in some instances, trillions of gallons of water can be trapped by a moraine, a formation of mixed rock, which forms a natural dam.  A weakening over time, or a sudden event, such as a landslide, could then result in the moraine dam’s collapse.

The massive amount of water is suddenly then released, and a wall of debris-filled liquid speeds down the mountainside with a destructive force capable of leveling entire city blocks.

GLOFs have presented an ongoing risk to people and their homes dating back to 1703, especially in the Cordillera Blanca region, according to United States Geological Survey records.  In December of 1941, a breach in the glacial moraine restraining Palcacocha Lake led to the destruction of a significant portion of the city of Huaraz and killed approximately 5,000 people.

Looking north over Huaraz towards the highest region of the Cordillera Blanca (Source: Uwebart/CC).

Scientists and government agencies, like the Control Commission of Cordillera Blanca Lakes created by the Peruvian government following the 1941 GLOF, have recognized the need to better understand and control GLOFs.  The study found that as global temperatures rise and glaciers retreat, greater amounts of glacier melt water will continue to fill up mountain lakes, chucks of ice will fall off glaciers, and  wetter moraines will become  more prone to landslides.

The team of mostly Czech geologists and hydrologists (J. Klimeš; J. Novotný; I. Novotná; V. Vilímek; A. Emmer; M. Kusák; F. Hartvich) along with Spanish, Peruvian and Swiss scientists (B. Jordán de Urries; A. Cochachin Rapre; H. Frey and T. Strozzi) investigated the ability of a glacial moraine’s slope to stay intact, called shear strength, and modeled the potential of landslides and falling ice to cause GLOFs.

After extensive field investigations, calculations and research into historical events, the study found several causal factors that can determine the severity of a GLOF.  These include size and angle of entry of a landslide,  shape and depth of the glacial lake, glacier thickness and human preventative engineering such as canals and supporting dams.  Frequency and size of a landslide is determined by the stability of surface material, a characteristic called shear strength, which can be influenced by something as subtle as the crystalline shape of the predominant mineral in the rock.

The terminal and lateral moraines that contain Palcacocha Lake, showing the 1941 breach that released a GLOF that devastated the city of Huaraz (Source: John Harlin/The Glacial Lake Handbook).

The scientists determined that waves caused by moraine landslides and falling ice would most likely lead to over-toppings of the natural dam.  An example would be the 2003 Palcacocha Lake GLOF, which was caused by falling ice.  No one died in this flood, but sediment from the floodwaters blocked the Huaraz’s main water treatment facility, leaving 60 percent of the population without drinking water for six days.  Additionally, small events like the one in 2003 weaken the natural and manmade dams, which without monitoring could eventually give out and result in a more catastrophic occurrence.

Most recent measurements estimate Palcacocha Lake holds 4.5 trillion gallons of glacier meltwater, which is enough to fill approximately 6,800 olympic size pools.  The potential of a catastrophic flood following the collapse of the moraine dam is a serious threat to the growing city that lies beneath it.
“Climate-driven environmental changes may critically affect stabilities of slopes above glacial lakes, possibly triggering large moraine landslides,” write the authors in the article.  They call for continued monitoring of glacial lakes.

First global analysis of the societal impacts of glacier floods

Two British researchers recently published the first global inventory and damage assessment of the societal consequences incurred by glacial lake outburst floods (GLOFs). They revealed that glacial lake outburst floods (GLOFs) have been declining in frequency since the mid-1990s, with the majority released by ice dam failures.

Glacial hazard specialists Jonathan Carrivick and Fiona Tweed spent 18 months scouring the records of over 1,348 GLOFs, determining that such floods have definitely claimed over 12,400 lives since the medieval period. Their work stems from a need to strengthen data on glacier lakes.

Glacier lake outburst at AP-Olsen Ice Cap, Greenland (Source: Gernot Weyss)
Glacier lake outburst at AP-Olsen Ice Cap, Greenland (Source: Gernot Weyss)

“There was very very little quantitative data out there on the importance of glacier lakes, from a societal point of view,” Carrivick said in an interview with GlacierHub. He explained that this recent paper was a natural progression from his earlier research, which focused on modelling hydrological, geological and geomorphological processes.

Based purely on frequency, Carrivick and Tweed found that north-west North America (mainly Alaska), the European Alps (mainly Switzerland), and Iceland are the “most susceptible regions” to GLOFs. However, the impacts of these events have have often been minimal, as they occur in sparsely populated, remote regions, and in places where resilience is high.

The greatest damage has been inflicted upon Nepal and Switzerland — respectively accounting for 22 percent and 17 percent of the global total damage reported. When Carrivick applied the normalized ‘Damage Index,’ which considered GDPs of the affected country (used as a crude proxy for ability to mitigate, manage and recover), he found that Iceland, Bhutan and Nepal have suffered the “greatest national-level economic consequences of glacier flood impacts.”

Historically, Asian and South American GLOFs have been the deadliest, taking the lives of 6,300 and 5,745 individuals since 1560 respectively. However, these figures are dominated by only two catastrophes, which accounted for 88 percent of the 12,445 fatalities confirmed by Carrivick and Tweed. The first, in December 1941, saw over 5,000 Peruvians perish in Huaraz, when a landslide cascaded into the glacial Lake Palcacocha. The second event, swept away more than 6,000 Indians from across Uttarakhand in June 2013, as torrential rains triggered outburst floods and landslides.

The city of Huaraz, devastated by the 1941 GLOF (Source: The Mountain Institute)
The city of Huaraz, devastated by the 1941 GLOF (Source: The Mountain Institute)

The study’s authors adopted a method for normalizing damage assessments new to GLOF hazard analysis, striving to fairly compare the cataclysmic impacts of outburst flooding on communities around the world.

They found that there has actually been a decline in number of floods since the 1990s, which was surprising to the researchers, given that a 2013 study which they had conducted found that the number and size of glacial lakes has increased, as the world’s ice masses have wasted. Carrivick stated that he was “very interested in the fact that, apparently, so few glaciers have lakes that have burst [0.7% of the total], on a global scale.” He added, “it beggars belief that there isn’t a higher percentage of those lakes that have burst at some point.”

In their paper, the pair suggest that the “apparent decline” could be attributed to improved successful stabilisation efforts, natural resilience, greater awareness and preparedness in threatened communities, or declined number of GLOFs from ice-dammed lakes.

An additional factor may be that some glacial floods are missing from the English-language record. Carrivick revealed, “We have a contact in China who says that there’s a lot of unpublished floods…that individual has not been able to send us the data yet.” Government restrictions on the flow of potentially sensitive information has contributed to this partial release of data.

Carrivick also noted that new data is continually being published, in many cases in foreign languages. He referenced a recent issue of the Geological Journal, which released “a whole heap of extra data,” translated from Russian.

Academics have been actively studying GLOFs since at least 1939. But it was not until 1996 that the first relatively comprehensive, global-scale inventory was compiled and published by Joseph Walder and John Costa, who recognized the “flood hazards posed by glacier-dammed lakes.” Carrivick and Tweed found the failure of this type of dam was the leading cause of GLOFs, accounting for 70 percent of events around the world.

Mark Carey studies Palcacocha Lake, Peru (Source: SSRC)
Mark Carey studying Palcacocha Lake, Peru, site of a major GLOF event (Source: SSRC)

Earlier this year, GlacierHub wrote about an alternate database, which has been compiled under the oversight of the International Programme on Landslides glofs-database.org. The project has been led by Adam Emmer, a PhD working with Vít Vilímek at Charles University in Prague. Three years ago, Emmer, Vilímek, and their team sought to compile a comprehensive global database, identifying over 500 events since the mid-1800s.

The work of Emmer and Vilímek’s team, like Walder, Costa and many others, predominantly focused on physical processes, such as the mechanisms which set off GLOFs, flood routes and distance, volume, as well as the quantity of debris carried by the floodwaters. Documentation of the socioeconomic impacts has remained been relatively less developed in glacial hazards research.

Noting this shortcoming, Carrivick and Tweed decided their study should focus specifically on the societal consequences of GLOFs. They included the number of deaths, injuries, evacuees, displaced, structural damage, financial loss, and called for the inclusion of less tangible social impacts in future studies, including Post-Traumatic Stress Disorder (PTSD). They also acknowledged potentially positive effects of floods, such as increased power generation at hydropower facilities.

They developed a ‘Damage Index,’ which allowed them to conduct standardised assessments of the impacts each GLOF had on downstream communities. This was by no means easy or straightforward. As Carrivick noted, “A footbridge going down in Bhutan has a very different impact to a footbridge going down in Alaska. One is absolutely vital to the functioning of society, and the other one probably receives ten tourists in a year.” They sought a methodology for normalising the heterogeneous impacts of GLOFs around the world, ultimately choosing the ‘Natural Disaster Impact Assessment’ (NDIA), developed by Olga Petrucci of the Italian National Research Council.

Regional and global GLOF figures, according to Carrivick & Tweed, 2016)
Regional and global GLOF figures, according to Carrivick & Tweed, 2016

The authors decided that the damage investigation should be conducted by Carrivick alone, who assigned a “relative score” to each event, as they sought to “provide a quantitative comparison.” Carrivick spent six months trawling through the records of 332 GLOFs (24 percent of the total) for which the societal impacts were known.

Carrivick emphasised that he and Tweed were “indebted” to the teams that have established the various comparable databases, which provided them with a “running start.” However, in reviewing their data they found that “whilst several natural hazards databases purport long-term records, they are in reality biased towards more recent events.” 

The researchers note the reality that GLOF-related research and mitigation activity at potentially hazardous sites is costly. Lack of funds has plagued efforts around the world. Both proactive (i.e. glacial lake research, continuous monitoring, mitigation works), and retroactive (i.e. repairs, reparations) initiatives are often low on national to-do lists, especially where resources are limited.

Stranded pilgrims cross a river swollen by GLOF waters in Uttarakhand, India (Source: AP)
Stranded pilgrims cross a river swollen by GLOF waters in Uttarakhand, India (Source: AP)

Carrivick and Tweed are hoping that their latest paper will establish an important foundation, upon which affected nations and colleagues can build. “It’s not wagging the finger at all, and saying ‘You can’t cope’ or ‘You can’t manage,’ but it’s identifying where we might strategically invest scientific work, and invest international collaborative efforts,” said Carrivick.

Education Fuels Disaster Resiliency in Northern India

In the Northern Indian states of Jammu and Kashmir, accelerated glacier melting in the Ladakh region has made communities increasingly vulnerable to glacier lake outburst floods, or GLOFs. These unpredictable natural disasters occur when glacier meltwater creates lakes at high elevations, which have the potential to overflow and cascade down the steep slopes of mountains.

As temperatures in the Himalayan region continue to climb due to climate change, the number of glacier lakes in Ladakh has surged to over 266 as of 2014, making outburst floods an acute risk in the region.

glacier lakes form from retreating glaciers in the Himalayas. Image provided by Jeffrey Kargel, USGS/NASA JPL/AGU
glacier lakes form from retreating glaciers in the Himalayas. Image provided by Jeffrey Kargel (USGS/NASA JPL/AGU)

While engineering and infrastructure projects can decrease the chances of an outburst flood, many remote, high altitude communities in India do not have the economic means or technology to build expensive mitigation structures that could halt the effects of GLOFs. However, a recent study conducted by Naho Ikeda, Chiyuki Narama, and Sonam Gyalson found that community-based measures like engagement and education may provide an alternative path to increased GLOF resiliency in Ladakh.

The Switzerland-based International Mountain Society (IMS) conducted the study in India, published earlier this year in the journal Mountain Research and Development. The research team developed a series of community workshops in Domkhar, a village in Ladakh that is a high risk community with at least 13 glacier lakes located in the watershed. The idea was to determine whether education and outreach were viable tools for protecting the villagers from glacier lake outburst floods.

Domkhar-Gongma village. Houses and agricultural fields are situated close to the stream on the slopes of old alluvial cones and colluvial footslopes. (Photo by Chiyuki Narama, 7 September 2012)
Domkhar-Gongma village. Houses and agricultural fields are situated close to the stream on the slopes of old alluvial cones and colluvial footslopes. (Photo by Chiyuki Narama, 7 September 2012)

The workshop, held in May of 2012, brought together 120 community members, scientists, and translators to discuss a wide range of topics on glacier lake outburst floods. Over the course of four sessions, Ikeda and her colleagues discussed their findings from a 2010 field survey of local glacier lakes and distributed an informational booklet written in Ladakhi, the predominant local language. The workshop also gave researchers insight into the community members’ cultural practices, religious beliefs, and current understanding of the impacts of climate change on their local environment.

The researchers’ concluded from their time in Domkhar that community members had a mixed level of knowledge of GLOFs and their associated risks. According to the report, community members expressed an understanding of glacier lakes and GLOFs that relied on a combination of their personal experiences with nature and their religious beliefs.

One group of villagers explained that sacred animals, including horses and sheep, cause outburst floods when the community angers them. Others mentioned that the lakes are sacred because the Tibetan Buddhist temples throughout the region are reflected on the surface of the water. Religion was predominantly mentioned by older members of the community rather than younger villagers, reflecting the fact that cultural identity has played a large role in the Ladakhi community’s understanding of the natural world, although that notion may be shifting with younger generations.

Photograph of the 9 stupas at Thiksey Gonpa (wiki)
Photograph of the 9 stupas at Thiksey Gonpa, a Tibetan Buddhist monastery in Ladakh (wiki)

A larger number of workshop participants also discussed their observations of nature, including the animal species and local geography surrounding the glacier lakes. However, individual observations were not always accurate, as participants did not know how many glacier lakes were within the watershed or of the emergence of a new glacier lake in the area formed in 2011.

Over the course of the day, community members displayed a curiosity and increasing knowledge of GLOFs that led to the adoption of a 7-point resolution to respond to a glacier lake outburst flood. The resolution included the development of a community-based GLOF monitoring committee, establishment of an evacuation plan, and discouraging construction near stream banks. While these measures require time and effort on the part of Domkhar residents, new technology and financial support are not necessary for implementation.

Three months later, researchers returned to the village with hopes that their workshop had increased local understanding of the dangers of GLOF and made a lasting impact on the community. Results were predominantly positive, according to a follow-up survey—over half of the interviewees reported a greater understanding of glacier lake outburst floods and countermeasures to respond to a natural disaster. Even members who had not attended the workshop showed improved understanding, indicating that the information had spread throughout the community.

Mountains lining the western shore of glacial lake Tso Morari, Ladakh (Sam Inglis)
Mountains lining the western shore of glacial lake Tso Morari, Ladakh (Sam Inglis)

However, the rise in awareness within Domkhar did not necessarily translate into action. Only half of the villagers interviewed said they made preparations for flooding since the workshop. These findings indicate that awareness and education can reduce a community’s social vulnerability to natural disasters by making resiliency a community-backed effort, but cannot stand alone as the only resiliency measure. Economic and geographic barriers in the remote villages of Ladakh make implementation of GLOF countermeasures a challenge, even for the most committed communities.

 

Preparing Peruvian Communities for Glacier-based Adaptation

Projects Fair, Santa Teresa
Projects Fair in Santa Teresa (Photo: CARE Peru)

As climate change quickens the pace at which Andean glaciers are melting, Peruvian communities located downstream from glaciers are becoming increasingly vulnerable to natural disasters.

The Peruvian national and subnational governments, the Swiss Development Cooperation, the University of Zurich, and the international humanitarian group CARE Peru have executed a collaborative multidisciplinary project to help two affected communities respond to glacier retreat and the increased risk of disaster. The first phase of the project ran from November 2011 through 2015. The project’s second phase, which is expected to run from 2015 to 2018, continues its work of risk reduction and climate change adaptation, while expanding its scope to hydropower production research.

Peru is home to one of world’s largest concentrations of tropical glaciers, most of which are located in the Cordillera Blanca in the Ancash region, along a section of the Andes in north central Peru. The Cordillera Blanca contains more than 500 square kilometers of glacier cover, accounting for roughly 25 percent of the world’s tropical glaciers.

High mountain ecosystems such as the Cordillera Blanca are no stranger to major geophysical events, such as ice and rock avalanches, debris flows, and glacial lake outburst floods (GLOFs). Glacier lake outburst floods are considered to have the most far-reaching impacts of any other glacial hazard.

Laguna 513
Laguna 513, a glacial lake in Ancash. (Photo: CARE Peru)

In the last few decades, Peru has already experienced several major natural disasters due to glacier melt and subsequent flooding. In 1970, a major earthquake in Ancash activated a glacial lake outburst flood and subsequent debris flow that destroyed the town of Yungay, killing around 20,000 people. More recently, in April of 2010, glacial lake Laguna 513 in the Ancash region triggered a flood outburst that created significant property damage in the downstream town of Carhuaz, which is home to roughly five thousand people.

In order to mitigate the risk of future natural disasters, this collaborative project worked from 2011 to 2015 to enhance the adaptation capacities of two communities located downstream of glaciers: Santa Teresa, in Cuzco, and Carhuaz, in Ancash. The project aimed to better prepare and equip these two communities to deal with the threat of glacial lake outburst floods by creating specialized integrated risk reduction strategies.

In Santa Teresa, a micro-watershed area of the Sacsara River, the project installed an comprehensive monitoring system, which provides the town with early flood warnings via radio communication tools, provided localized risk analysis, and supported the creation of community and municipal development plans, as well as the integration of emergency plans into 17 local schools.

The Early Warning System in Carhuaz, Ancash.
The Early Warning System in Carhuaz, Ancash (Photo: CARE Peru).

In Carhuaz, project collaborators helped the municipality establish a water resources management committee in order to increase the capacity of local and interagency decision-makers to collaborate in managing risk. The project also installed an early-warning system for glacier outburst floods, as well as planned evacuation routes and disaster responses. The project implemented curriculum plans containing climate change adaptation and risk management into 30 schools in Ancash. The project’s various scientific and technical experts also conducted flood scenario models, which they shared with local decision-makers to help identify areas of potential risk.

Children in local schools learn about glaciers and climate change
Children in local schools learn about glaciers and climate change in their community (Photo: CARE Peru).

To date, the project has trained more than 90 public officials, agency staff, and university professors on climate change, adaptation, and risk management measures. CARE Peru estimates that the project has directly benefited over six thousand people in these Carhuaz and Santa Teresa, and has indirectly benefited many more.

The project particularly emphasized gender and power dynamics that contribute to vulnerability. The project trained local leaders on gender equality issues and women’s empowerment and encouraged balanced gender participation in the adaptation planning for both communities. 

Integrated Water Resources Management.
Integrated Water Resources Management in practice (Photo: CARE Peru).

University of Zurich glaciologist and project contributor Christian Huggel remarked that the project is “the first of its kind in Latin America, especially in its social aspect of training leaders and strong local inclusion.” He described the project as a “pilot in particularly extreme conditions”: Contributors encountered many technical problems throughout its first phase of implementation, including energy supply access and a lightning strike on technical equipment, he explained, rendering it a “learning process” for all involved.

The project’s second phase expands the project’s scope to the exploration of opportunities for public-private partnerships to create hydropower production in the community.

“This aspect of the project is founded on the belief that the private sector should be more involved in local communities’ climate change adaptation, especially with concerns of funding,” Huggel said. This plan could help these innovative projects become economically sustainable, assisting them in moving beyond their first phase of reliance on international aid— a step that is increasingly attracting attention with groups that work on adaptation issues.

 

Military intervention at Nepal’s fastest growing glacial lake

Ten kilometres south of Mount Everest lies Nepal’s “fastest-growing glacier lake”— Imja Tsho. In March 2016, acting to mitigate potential threats the lake might pose to over 96,000 people downriver, the Nepalese Army began installing syphons to lower the water level by 10 feet (3 m).

The army’s engineering department, commissioned by Nepal’s Department of Hydrology and Meteorology (DHM), is now conducting “the highest altitude disaster risk mitigation work ever performed by any army in the world,” according Lt Col Bharat Lal ShresthaLocally, the remediation will bolster the confidence of flood-prone communities, and is likely to assuage fears of downstream developers, which have been concerns elsewhere in the region.

The soldiers can only work two to three hours a day, due to the thin air, and strain of working at 16,400 feet (5,000 m). The project aims to safeguard lives, livelihoods, and infrastructure throughout Solukhumbu District — home to Mount Everest and the major religious site of Tengboche Monastery — as well as further downstream.

The United Nations Development Programme (UNDP) and Global Environment Facility (GEF) — the world’s largest fund addressing environmental issues — are financing the US$7.2 million remedial works at Imja Tsho,  often cited as an especially dangerous lake. This has been reinforced by local perceptions and its proximity to Everest’s trekking routes.

Imja Tsho and the surrounding Everest region (Source: NASA Earth Observatory, annotated)
Imja Tsho and the surrounding Everest region (Source: NASA Earth Observatory, annotated by Sam Inglis, GlacierHub)

A report by the  BBC in June 2016 claimed that the 2015 Gorkha earthquakes “may further have destabilised” the lake. However, the results of ’Rapid Reconnaissance Surveys’ made public in December 2015 revealed “[Imja] showed no indication of earthquake damage when viewed either by satellite or by a helicopter.

The UNDP and GEF’s selection of Imja pivots on a single study by International Centre for Integrated Mountain Development (ICIMOD) from 2011, which defies much of the preceding and independent research on the lake. ICIMOD is an intergovernmental agency headquartered in Kathmandu, researching Nepal’s glaciers and mountains hazards and also involved  in the current engineering works.

Studies by Japanese, British and American teams concluded that the surrounding topography shelters Imja from mass movements. ICIMOD deprioritized Imja’s status. Their 2011 national report stated, “[despite] the apparently alarming rate of [Imja Tsho’s] expansion…the danger of outburst came to be regarded as far less than originally expected.” Concurring with the international researchers, they also ruled out the possibility of a GLOF-triggering ice avalanche as ”[not] very likely.”

The lead authors of the 2011 study subsequently gave compelling evidence in 2015 for remediation at another glacial lake — Thulagi Tsho. Narendra Raj Khanal and six colleagues from ICIMOD revealed Thulagi posed a “high risk.” Over 164,000 people would be directly impacted by a Glacial Lake Outburst Flood (GLOF), with a further 2 million indirectly exposed — four times the number at Imja. Threats to hydropower facilities were a key concern highlighted by UNDP and GEF. However, there are six hydropower projects below Thulagi, and one below Imja.

Imja is being drained 10 feet (3 m) over 4 years — costing nearly US$7 per gallon. However, research led by the University of Texas has shown that this minor reduction would have a negligible impact on a GLOF. Daene McKinney and Alton Byers also stated that it offered an insignificant “3 percent risk reduction.”

Imja Tsho presently covers 135 ha (1.35 km2), holding nearly 20 billion gallons (75.2 million m3) of meltwater — enough water to meet all New York State’s water needs for nearly two and a half days. It is fed by Imja Glacier, which has wasted 1.4 miles (2.2 km) over less than 40 years. Imja Glacier has “exhibited the largest loss rate in the Khumbu region,” according to research by the University of Texas and The Mountain Institute.

The evolution of Imja Tsho from 1976-2016 (Source: USGS Landsat Archive)
The evolution of Imja Tsho from 1976-2016 (Source: USGS Landsat Archive)

Nepal began inventorying its glaciers and glacial lakes in earnest in 1999 — “after global warming had become a sexy topic,” claimed independent observer Seth Sicroff. ICIMOD publishing the findings in 2001. They detected 2,323 glacial lakes, classifying twenty — less than one percent —as “potentially dangerous.”

GLOFs, which typically occur when a dam barring a glacial lake fails, gained greater attention as a point of investigations in the 1980s, following a catastrophic outburst at Dig Tsho. At the “request” of Khumbu residents, German geoscientists Wolfgang Grabs and Joerg Hanisch travelled to the Everest region in 1993 to study local glacial hazards, and establish an hazard assessment criteria. They speculated that syphoning water, and lowering the level by 16.4 feet (5 m) could “stabilize” lake against overtopping surge waves pouring over the dam.

The syphon was first adopted at Tsho Rolpa — Nepal’s largest glacial lake — in May 1995. By 1998, following 4 years of investigations, Professor John Reynolds — then-chief technical adviser on glacial lakes to the Nepalese government — designated it the “most dangerous glacial lake in Nepal.”

A repeat of the 1985 GLOF has long been feared in Rolwaling Valley — a mere 6 miles (10 km) east of Dig Tsho. The DHM projected Tsho Rolpa could release of over 8 billion gallons (30 million m3) of meltwater — threefold the volume of 1985 GLOF, and equivalent to the volumes of 12,000 olympic swimming pools. Over 10,000 local inhabitants, and US$22 million-worth of infrastructure and property as far as 62 miles (100 km) down-valley, were thought to be threatened.

In 2013, a Japanese research team revealed that the “potential flood volume” at Tsho Rolpa has tripled, and is now closer to 23.6 billion gallons (89.6 million m3).

By July 2000, a 13 foot (4 m) US$3.1 million spillway had been constructed, reducing the water level by 9-13 feet (3-4 m). Reynolds recommended that engineering works be continued until the lake level was 49-65 feet (15-20 m) below its 1998 level. Five DHM experts and Reynolds co-authored a paper emphasising, “While the lowering of the lake level by [9.8 feet] 3 m [was] expected to reduce the risk of GLOF, it is not a permanent solution.” Their explicit intention was to continue lowering in the “near future,” as soon as funds were allocated for disaster mitigation in Nepal.

Sluice gate at Tsho Rolpa (Source: Brian Collins/USGS)
Sluice gate at Tsho Rolpa (Source: Brian Collins/USGS)

Funds were never found and, in the early 2000s, Maoist insurgents infiltrated the area. They dismantled Tsho Rolpa’s ‘Community-Based Early Warning System’ (CBEWS) in 2002. It was not until 2012 — a decade after the insurgence had been quelled — that replacements were pledged. The CBEWS was expected to be back online in early 2016.

A misplaced “trust in western technology” resulted in locals complacently believing there was “no further danger,” according to anthropologist Dr Janice Sacherer of the University of Maryland. This sentiment persists, and no further work has been budgeted for Tsho Rolpa in the near future. This is largely attributable to the limited funds available to the DHM, who receive a bulk of their funding from international NGOs, aid agencies and foreign governments.

It has been long been hoped that funds would be diverted to counter the immediate threat posed by Tsho Rolpa. The UNDP’s 2013 technical report stated 141,911 people within 62 miles (100 km) of Tsho Rolpa are exposed to the direct impacts of a GLOF, compared to the 96,767 living 75 miles (120 km) below Imja Tsho. However, the UNDP report justifies its decision to focus on Imja by revealing that the economic toll through lost revenue at Imja would be US$8.98 billion — nearly four times that downstream of Tsho Rolpa.

In 2007, under-development of the Rolwaling Valley was attributed, at least in part, to the omnipresent threat of a massive GLOF.

With a US$7.2 million price-tag, a military cohort that can only work a few hours a day, other sites requiring more immediate attention, and the syphoning method being deemed a “Band-Aid solution,” only time will tell if the money and effort expended on Imja Tsho were warranted.

Massive 1929 Himalayan Flood is a Cautionary Tale

Glacial lake outburst floods, known as GLOFs, have been a core focus of mountain research in recent years. Interest has grown as glacial lakes have developed and started to threaten communities and infrastructure. In March, GlacierHub covered the growing GLOF database, overseen by the International Consortium on Landslides. Since the beginning of 2016, 32 peer-reviewed, English-language papers examining GLOFs and their impacts have been published online. Half explicitly focused on changes across the Hindu Kush Himalayan (HKH) region.

Glaciers in the HKH region have lost up to 55 percent of their mass since the 1980s, according to a study by the International Centre for Integrated Mountain Development. And glacier-fed lakes in the Central Himalayas grew in surface area by 122 percent between 1976 to 2010, research led by Weicai Wang of the Chinese Academy of Sciences found.

One area in the HKH is of particular interest: the Shyok system. The Shyok River catchment, a tributary of the Indus, has been unleashing powerful GLOFs on the Indus since 1533. In 2013, Kenneth Hewitt and Jinshi Liu examined the catchment via satellite data, providing the most recent analysis to date. Located in northern Pakistan’s Karakoram Range, 25 miles (40 km) east of Siachen Glacier, the valley has been “inaccessible because of security issues” according to Hewitt and Liu

Satellite image of Shyok Valley, with key features annotated (source: LANDSAT)
Satellite image of Shyok Valley, with key features annotated (source: LANDSAT)

Shyok’s reputation is a result of the characteristic behaviors of its glaciers, which have a tendency to surge. This means they unpredictably slide down the tributary Chong Khumdan, Sultan Chussku, and Kichik Khumdan valleys and block the flow of the Shyok River. The three glaciers of Chong Khumdan valley— North, Central and South— are the most active, and are thought to have dammed the river 13 times between 1826-1933.

However, since the last GLOF of 1933, the Shyok system has gone quiet.

Hewitt, who has studied the catchment for over 30 years, in 2013 designated the Chong Khumdan Glaciers as posing an “immediate, high risk” of blocking the Shyok River and unleashing a GLOF, based on satellite imagery from 2009. Despite the lateral thinning of each glacier’s trunk, the terminus of the combined North and Central Chong Khumdan Glaciers advanced 1.4 miles (2.2 km) between 1991-2013. The South Chong Khumdan Glacier moved more slowly, nudging forwards 0.16 miles (250 m) over the same period. However, the system has surged to the extent that the Shyok River presently flows through a gap of only 200 feet (60 m).

In a 2007 paper, Hewitt determined that glaciers in the Karakoram can surge up to 4.3 miles (7 km) within a matter of months. He also found that regional surging glaciers have been especially susceptible to recent changes in regional climatic conditions.

The experiences in 1928 and 1929 of a little acknowledged biologist, Frank Ludlow, tell a powerful story about the impacts of the last major GLOF released by the Shyok system.

A photograph of the Chong Khumdan Glacier dam and lake, captured by Frank Ludlow three days before the 1929 GLOF. (source: The Himalayan Journal)
A photograph of the Chong Khumdan Glacier dam and lake, captured by Frank Ludlow three days before the 1929 GLOF. (source: The Himalayan Journal)

In 1929, The Himalayan Journal published his findings. A lake had formed as a result of the eastward migration of the Chong Khumdan Glaciers. The glacier had connected with the valley side, and was blocking the meltwaters from a large Rimo Glacier system upriver. Extending 10 miles (16 km) from tip to tip, the lake was shaped like “an irregular crescent with its two horns pointing north-west and south.”

He had judged that it averaged 150 feet (45 m) in depth, and within a 24-hour period, as he camped along the eastern shoreline, the water-level had risen 1.5 feet (45 cm). He estimated that the water was likely rising by 4.5-9 inches (11-22 cm) daily. Ill-equipped to study the lake in any greater detail, Ludlow departed from Shyok within a week.

The next year, he returned, accompanied by J.P. Gunn, an officer of the Punjab Irrigation Department. The lake had grown to 11 miles (18km) in length. The ice dam was beginning to feel the strain. In 1930, Gunn wrote in The Himalayan Journal:  “All the time we were down at the dam on 12th August loud creaks and ‘groans’ were heard, lasting some time, as ice‐floes broke off the main body.”

Three days later, the Chong Khumdan Glacier dam broke.

Satellite imagery of the flood path, with key variables from 1929 GLOF displayed in the table. (source: NASA)
Satellite imagery of the flood path, with key variables from 1929 GLOF displayed in the table. (source: NASA)

An estimated 356 billion gallons (1.35 billion cubic meters) of water was released on August 15, 1929— enough to fill 540,000 Olympic swimming pools. Gunn observed a “dark chocolate‐coloured flood,” and judged that 10.5 million cubic feet (300,000 cubic meters) of ice were borne off by the floodwaters. The wall of water, mud, and debris stood 85 feet (26 m) high, and travelled a staggering 930 miles (1500 km) down the Indus. Even 740 miles (1194 km) downriver, the flood waters swelled the river up to 26 feet (8 m).

Were a glacial lake in Shyok to form now, it would pose a dire and immediate threat to more than two million people who inhabit downriver. Hundreds of villages, cultivated lands, and infrastructure, including the Karakoram Highway and Tarbela Dam, are at risk. What’s more, glacial lakes in this catchment are known to form and collapse within less than two years.

Building a Database of Dramatic Glacial Floods

Glacial lake outburst floods are a type of deluge that occurs when a moraine–a natural dam, made of rock, sediment and ice–breaks, releasing the glacier-fed lake behind it. As a consequence, some scientists have said that it is necessary to build a database of past glacial lake outburst floods to manage and monitor the threat of future ones.

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Rockslide flood on the Hunza River in Pakistan (source: NASA)

A recent paper by Adam EmmerVít Vilímek, Christian Huggel, Jan Klimes and Yvonne Schaub in the journal Landslides, “Limits and challenges to compiling and developing a database of glacial lake outburst floods,” reports the challenges that scientists faced when compiling and developing such a database.

The database, with its list of glacial lake outburst floods (GLOFs), can be found here. The earliest flood listed in the database occurred in 1790 in the Patagonian Andes and one of the most recent happened in 2012 in the Peruvian Andes. The database also includes what triggered the flood, with evocative descriptors like “rockfall / landslide into lake,” “earthquake,” and “icefall / snow avalanche into the lake.”

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Sabai Tsho Lake before the moraine dam breach. (Source: treks.org)

The International Programme on Landslides started the database project in 2013. The specific goal was to collect data and create an accessible database of glacial lake outburst floods that have occurred across the globe. Many sources were used for the database construction: the worldwide real-time database of earthquakes provided by USGS, the NatCatSERVICE database of major disasters managed by Munich Reinsurance (Munich RE 2003), and other global databases. To be specific, a GLOFs-inventory compiled for Europe in support for the Glaciorisk project, contains 333 GLOFs in the Alps and 85 in Iceland as well as ice avalanches caused by ice-dammed lakes.

By the end of October 2015, around one hundred GLOFs, only one fifth of the total number, were chronicled on the website. But more GLOFs are being gradually added from region to region.  

There is increasing demand for a natural disaster database construction considering that the frequency of extreme events is on the rise. Scientists who did researches in this field gradually find the necessity of building such a database. Glacial lake outburst floods have become one of the most studied issues and thus the database construction has drawn great attention. The database can be roughly divided into the global and regional databases and case studies. The database of glacial lake outburst floods is on a global scale, trying to include glacial floods worldwide for easier access as well as more convenient scientific analysis. In order to construct the global database, the separate and detailed regional record should be unified and also updated with most recent outburst flood events, the case studies. Now the global glacial databases have 450 glacial lake data source.

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Glacier Lake Outburst Flood in northern Pakista (Source: weadapt.org)

There are some challenges in the process of database construction. With various types of data sources, the precision of the information about particular lake outburst floods is slightly doubtful.  It is generally agreed that the source of scientific papers is the most reliable. As for improving the data validation, scientists believe that the involvement of local experts who master the regional knowledge related to glaciers to verify the data source should be added into the procedure.

The database construction has received broadly positive feedback especially from the scientific community according to the data requests and availability and has begun to serve as a collaboration platform for different scientific institutions worldwide, although setbacks and limitations still exists. With precise data of glacier such as its movement over the slope below, it is a convenient way for scientists to conduct research, hazard analysis. The analysis result can even be used for insurance companies with the assessment of disaster levels, the paper argues. Considering its great importance in risk assessment and disaster analysis, progress including the involvement of local experts should continued to be made for the development of the glacial lake outburst floods database in the future.

 

Roundup: Modeling Floods, Water Security, and Farmland

Each week, we highlight three stories from the forefront of glacier news. 

Modeling glacial lake outburst flood process chain: the case of Lake Palcacocha and Huaraz, Peru

From Hydrology and Earth System Sciences:

“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 5 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 1800 people in the city of Huaraz, Peru.”1

To learn more about the research, click here.

Forum reveals new possibilities for water-induced disaster management in the Koshi basin

From ICIMOD:

“Top officials and experts from the Koshi region gathered in Patna, Bihar on Thursday for a two-day forum to discuss solutions around water security and water-induced disasters in the Koshi basin. Coming after years of devastating floods in southern Nepal and Bihar, the forum emphasised regional cooperation and collecting evidence-based data that can be translated into policy.”2

To learn more about the research, click here.

The Changes in Regional Structure and Land Use Related to External Factors in Hussaini Village, Northern Pakistan

From Mapping Transition in the Pamirs:

“This study describes changes to regional structure and the use of farmlands in Hussaini village, Pakistan, caused by two events. The first event was the opening of the Karakoram Highway in 1978 that introduced commodities and a money market economy. The enhanced transportation increased access to markets, which spurred a transition from subsistence wheat cultivation and vegetable crops to potato cash crops. The second event was the catastrophic landslide in Atabad which occurred on 4 January 2010 that submerged part of the Karakoram Highway and created a dammed lake. The loss of the highway halted the village’s engagement in the wider agricultural market, and farmlands in the village reverted to traditional agriculture. The changes caused by these outside factors created confusion and disturbance and challenged the villagers to quickly adapt for survival.”3

To learn more about the research, click here.

Roundup: Droughts and Floods in the Future

15% Shrinkage for Tibet Glaciers

“Glaciers on the Tibetan Plateau – the source of rivers such as the Brahmaputra – have shrunk by as much as 15 per cent, retreating by 8,000 square kilometres since 1980, according to a new Chinese government-backed study.

The decades-long study conducted by the official Chinese Academy of Sciences (CAS) discovered that the perennial frozen earth on the Tibetan plateau had also shrunk by 16 per cent over the past 30 years.”

Upstream photo of glacier-fed Brahmaputra River, Courtesy of Boquiang Liao, Flickr
Upstream photo of glacier-fed Brahmaputra River, Courtesy of Boquiang Liao , Flickr.

Read more of the story here.

 

Nepali Communities in Fear of Glacial Melt Floods

“Pemba Sherpa looks fearfully at the huge Imjha glacier lake which lies at an altitude of nearly 6,000 metres above sea level in the Everest region of eastern Nepal…His house in Chukung village is only a few kilometres from the rapidly growing lake.”

"Flooded
Courtesy of Flickr User Suzanne Hitchen.

 

Read more of the story here.

 

Climate change: Melting glaciers bring energy uncertainty

“Running 2,000 kilometres from east to west and comprising more than 60,000 square kilometres of ice, the Hindu Kush–Karakoram–Himalayan glaciers are a source of water for the quarter of the global population that lives in south Asia. Glaciers are natural stores and regulators of water supply to rivers, which, in turn, provide water for domestic and industrial consumption, energy generation and irrigation.”

Pakistan's Tarbela Dam, along the Indus River, is fed by glacial water from the Himalayas. Image by © Christine Osborne/CORBIS
Pakistan’s Tarbela Dam, along the Indus River, is fed by glacial water from the Himalayas. Image by © Christine Osborne/CORBIS, USAID

Read more of the story here.

Roundup: French Presidential Visit, Trek Itinerary, and Dangerous Glacial Lakes

French president visits glacier to witness climate change

Francois Hollande
Iceland’s President Olafur Ragnar Grimsson, right, and France’s President Francois Hollande, left, talk on the Solheimajokull glacier, in Iceland on Oct. 16 (AP Photo/Thibault Camus, Pool).

“PARIS — The French president took a few steps on an Icelandic glacier Friday to experience firsthand the damage caused by global warming, ahead of major U.N. talks on climate change in Paris this year. Francois Hollande went to the shrinking Solheimajokull glacier, where the ice has retreated by more than 1 kilometer (0.6 miles) since annual measurements began in 1931.”

To read more about the President’s visit, click here.

 

How to find Yosemite’s disappearing glacier

Lyell Glacier
Photo of Lyell Glacier from 1903 on site at Lyell Glacier last week in high country of Yosemite National Park (Courtesy of Josh Helling, The Chronicle)

“The Lyell Glacier, once a mile wide and Yosemite’s largest glacier when measured by John Muir in 1872, could melt off and disappear in as soon as five years, according to park geologist Greg Stock, if warm temperatures at high elevations continue. Chronicle outdoors writer Tom Stienstra visited the park to report on the glacier’s vanishing. This is the trek itinerary.”

Click here to read more.

 

Global warming creating dangerous glacier lakes in Himalayas, finds study

Life-threatening flood from Chorabari lake in 2013 (Courtesy of the Hindustan Times)
Life-threatening flood from Chorabari lake in 2013 (Courtesy of the Hindustan Times)

“As the black clouds heavily pregnant with water vapour hovered over Dehradun on June 15, 2013, it looked ominous. Around 13,000 feet above the sea level, rain was already tanking up Chorabari Lake, a water body created by melting glaciers. On June 16 midnight, the heavy rain caused the lake’s rock bank to collapse, sending down a flash flood that swept through the holy Himalayan pilgrimage site Kedarnath, killing 5,000 people.

There are 1,266 such Chorabari lakes in Uttarakhand’s Himalayan regions, some of which have been created fresh by the rapid retreat of glaciers due to global warming, found a study by Wadia Institute of Himalayan Geology, an autonomous body of the central government.”

To read more about the study’s findings, click here.

 

Glacier Lake Bursts in Alaska

When Paul Gowen, 83, saw turquoise-green water spilling into the Frederick Sound and Wrangell Narrows in Alaska at the end of last month, he knew a glacier lake on the Baird Glacier had burst. Further up the Frederick Sound, residents noticed a larger quantity of icebergs and stronger currents.

“This is amazing, this turquoise color as far as we can see on Frederick Sound,” he told the local radio station, K-FSK, at the time. “It’s very unusual to have this much outwash of color.”

Outburst floods on glaciers are not uncommon — water accumulates within the ice or in dips, but eventually breaks through the ice barrier holding it in. The turquoise-green colour of the water comes from sediments that tend to accumulate in glacier lakes, often called glacial flour or milk. Climate change is expected to increase the risk of Glacial Lake Outburst Flooding as glacier melt accelerates, according to the World Wildlife Fund.

The last time a lake burst on the Baird Glacier was 1991, though the event was much smaller. Between 2000 and 2009, the glacier had lost 10 to 20 metres of thickness.  Later, glaciologist Mauri Pelto reported in 2013 that two large lakes 400-600 metres were expanding.

Closer investigation from the U.S. Forest Service in the area found that the most recent September flood likely originated in the Witches Cauldron branch of the glacier.

“There’s no water,” Jim Baichtal, Geologist for the U.S. Forest Service said. “It’s all gone and it looks like there’s been a tremendous amount of collapse of the surface of the ice.”

The glacier’s surface has new crevasses, sinkholes, and fractures. According to Baichtal, the surface may have sunk 50 or 60 feet after the flood.

Government officials will have to keep an eye on the glacier, as it will be hard to predict whether another flood is likely.

“You can really have a situation where a place essentially gets safer in terms of natural hazards or you can have the opposite,” said Martin Truffer, a glaciologist at the University of Alaska.

 

 

India’s Hydroelectric Plans Threaten Local Comunities

 

Indigenous Buddhist tribes in northeast India are protesting government plans to build fifteen new hydroelectric sites along their settlement region. The Monpa tribe, which lives along the Tawang river basin in over 234 scattered settlements in Arunachal Pradesh, fears that the hydroelectric projects will affect their religious sites and monasteries, as well as the region’s springs, and biological diversity, which carry large cultural significance for the tribe. The region is also at risk of Glacial Lake Outburst Floods (GLOFs), which could have hazardous impacts on hydroelectric projects.

Black Cranes
Black-necked cranes by a lake in Tibet. Courtesy of Purbu Zhaxi/Xinhua Press/Corbis

The government is proceeding with the construction of one particularly contentious hydroelectric site: a 780MW station along the Nyamjang Chhu river that threatens a cultural and religiously significant migration site of endangered black-necked cranes. This site will occupy the middle of a 3-km stretch of the Nyamjang Chhu river, which is partially fed by the region’s glaciers and along which eight black-necked cranes reside during their winter migration.  The Monpa eagerly await the birds’ arrival, and revere their species as the reincarnation of the sixth Dalai Lama.

In late July of 2015, the Save Mon Region Federation sent a letter to the Expert Appraisal Committee of the ministry, accusing NJC Hydropower, the independent company building the Nyanjan Chhu hydroelectric site, of purposely concealing information about the black-necked cranes’ wintering site. Allegedly, the company didn’t cooperate with the study’s researchers until the end of winter, when the black-necked cranes had left their wintering site.

A Monpa monk spins prayer wheels at Tawang monastery
A Monpa monk spins prayer wheels at Tawang monastery. Photo courtesy of Anupam Nath/AP

“The hydroelectric projects will totally destroy natural habitats in the region,” Asad Rahmani, scientific adviser of the Bombay Natural History Society, told the Guardian. “When planning such projects, we’re not paying attention to their impact on local culture. The electricity is for people like us in the cities, but all the damage is suffered by the local people.”

In addition to going ahead with the highly disputed site placement, the Dehli government has plans for another fourteen proposed hydroelectric projects in the Tawang region. These projects are part of major government efforts to bring power to the 300 million people living without electricity by 2022. The government will also increase solar, wind and coal generation in the next seven years.

“We don’t need so many hydel projects to meet the electricity demand of our people,” Save Mon Region Federation’s general secretary, Lobsang Gyatso, told the Times of India. “Small hydro-projects would suffice. All these large dams are meant to generate electricity to be sold outside, at the cost of our livelihoods and ecology.”

To express concerns about the new hydroelectric plans, villagers in the Tawang region organized a large rally in December of 2012. The protesters alleged that the government had developed hydroelectric projects with private utility developers without proper consent from the residents in the region. The region currently maintains a ban against public gathering.

In addition, the relatively unexplored, mountainous region in the Eastern Himalayas is especially prone to the risk of Glacial Lake Outburst Floods (GLOFs), as are most regions of this type, which poses risky problems to hydroelectric development.

GLOFs are one of the major hazards of mountainous, glacial regions, especially those susceptible to climate change. Tawang’s lakes and rivers are mainly supplied by snowmelt and the melting glaciers of the Himalayas. The lakes, while usually dammed by end-moraines, have a tendency to flash flood, which induces large volumes of flowing water, large quantities of sediment runoff, as well as potential flowing boulders and the risk of washing away mountain valleys. GLOFs are often responsible for catastrophic flooding, large losses of property, and human life.

While the region’s dams have a combined capacity of about 2800 MW of power, a recent study stated that GLOFs and their associated risk are likely to have a “direct impact” on the commissioned hydropower projects in the region, as well as on the Monpa population living downstream of the glacial lakes and hydroelectric projects.

The study aimed to detect potential dangerous lakes to proposed hydroelectric sites, as well as to quantify the volume of water discharge and to predict the hydrograph, or rate of flow versus time, at the lake sites at risk of GLOFs.  The researchers estimated that at peak flow, flooding at one particular dammed lake likely of flooding would take as little as an hour and ten minutes to reach a downstream hydroelectric site, posing great risk to the site. Despite promises from the governmental parliament, no public consultation on the Tawang river basin study report has yet been held.

The Monpa protestors remain focused on the threats the hydroelectric sites pose to their cultural and religious traditions. Each of the 234 Tawang settlements along the river will be affected by at least one hydropower plant, and construction for the sites will demolish roughly 615 acres of forest. Monpa residents also fear the disruption of sacred pilgrimage sites and springs.