Celebrating a Career of Mountain Highs: Professor Mark Carey Receives King Albert Mountain Award

This post was originally published by the Mountain Research Initiative in September 2018.

Mark Carey, professor of history and environmental studies at the University of Oregon, has received the prestigious King Albert Mountain Award for almost two decades of exceptional service to mountain research. We spoke to him about what this award means to him and his ongoing work to protect mountain societies and environments.

Mark Carey, professor of history and environmental studies at the University of Oregon (Source: Marco Volken/King Albert I Memorial Foundation).

The King Albert Mountain Award is granted to people and institutions that have made exceptional and lasting contributions to the preservation of the mountains of the world – whether through research, conservation, development, arts and culture, or mountaineering.

To date, the award has been granted to 57 recipients since its foundation in 1993. At an award ceremony in Pontresina, Switzerland, in September this year, Mark Carey, professor of history and environmental studies at the University of Oregon, joined their number for his contributions to mountain science. The other winners in this round of awards were the rock climber Nasim Eshqi (Iran), filmmakers Mario Casella and Fulvio Mariani (Switzerland), and the Val Grande National Park (Italy).

Spotlight on an Overlooked Field

“I am incredibly honored and humbled that they selected my research from among all mountain researchers across all disciplines and fields in all the world’s mountains,” says Carey. “And I am particularly thrilled that the King Albert Foundation recognized my work in environmental history, which offers social science and human-focused contexts for understanding the world’s mountains, glaciers, and changing climates – areas that are usually dominated by natural scientists, not social sciences and humanities, and which can often be overlooked by policymakers.”

Professor Mark Carey receives the prestigious King Albert Mountain Award (Source: Marco Volken/King Albert I Memorial Foundation).

So what exactly is Professor Carey’s research focus? “My work looks at how people are affected by changing glaciers, and how people adapt to long-term climate change in mountain regions where they live, and sometimes die, with the ice,” says Carey.

His award-winning book, “In the Shadow of Melting Glaciers: Climate Change and Andean Society,” analyzes 75 years of climate change adaptation in the Peruvian Andes, with a particular focus on how people struggle to understand and respond to glacial lake outburst floods, avalanches, and hydrologic changes. Other topics he has written about include national parks under climate change, the history of mountaineering, and alpine health resorts and climate therapy.

A More Complete Picture

As an interdisciplinary scholar, Carey can sometimes feel like his work straddles too many research areas. “I often feel without a disciplinary home,” he explains. “I have tried hard to practice cross-disciplinary research – but that often leaves one feeling like a fish out of water! A dabbler instead of a master of a single topic.”

“Truly interdisciplinary and integrative research can be difficult and time-consuming. And even though there is a lot of lip service in favor of it, interdisciplinary research is usually harder to publish, takes much more time, requires challenging conversations and collaborations with people who see the world differently, and is often under-appreciated by scholars trained in single disciplines.”

But it was this broader, interdisciplinary approach – and the way in which it helps us to build a more complete picture of mountains as complex social-ecological systems – that was viewed as a strength by the award committee. And that, says Carey, is hugely encouraging. “This international support and inspiration to continue my work on ice and human societies around the world is thrilling.”

Breaking Down Disciplinary Boundaries

However, although this award is evidence of interdisciplinary mountain research gaining increasing global recognition, Carey thinks there is still some way to go. “We desperately need more researchers in the social sciences and humanities in order to better understand mountain peoples and societies – but these researchers must also reach across disciplinary boundaries, do work in the field together, disseminate results together, and try to reach policymakers together,” he says.

Mark Carey (second from left) received his award at ceremony in Pontresina, Switzerland, in September 2018 (Source: Marco Volken/King Albert I Memorial Foundation).

By working with other researchers in this way, Carey feels it may be possible to have a greater impact. “I think my most significant contributions have all come through my collaborative work—with glaciologists, hydrologists, engineers, anthropologists, geographers, and sociologists,” he says. “Through collaborations, my colleagues and I have offered holistic approaches to glacial lake outburst floods, and proposed hydro-social modeling to understand glacier runoff and downstream water use, among other things.”

“This King Albert Mountain Award shows that these diverse and interdisciplinary approaches are on the right track,” concludes Carey. “It inspires me to keep up these efforts and to continue the quest to help sustain mountain peoples and environments.”

More information can be found on the King Albert Mountain Award website.


Mark Carey is a professor of history and environmental studies at the University of Oregon, where he researches the societal aspects of glaciers and climate change and runs the Glacier Lab for the Study of Ice and Society. He has published the award-winning book, “In the Shadow of Melting Glaciers: Climate Change and Andean Society” (Oxford, 2010), as well as a co-edited volume on “The High-Mountain Cryosphere: Environmental Changes and Human Risks” (Cambridge, 2015). He has held several National Science Foundation grants, been a contributing author for the Intergovernmental Panel on Climate Change (IPCC), and is a co-founder and co-director of the Transdisciplinary Andean Research Network (TARN). He is currently completing a book about the human dimensions of icebergs in the North Atlantic Ocean.

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Adapting to Glacier Retreat in Peru’s Huascarán National Park

The quickly receding Pastoruri glacier may not have too many years left at the rate it’s melting (Source: Joao Diniz/Flickr).

Environmental anthropologist Jessica O’Reilly stated in her 2017 book on science and policy, “While scientists usually act as spokespeople for ‘data,’ some materials may speak for themselves.” Melting glaciers, including the ones in the high Andes, are examples of materials that speak for themselves, acting as compelling visualizations of the concept of climate change.

A recent article in Regional Environmental Change by Mattias Borg Rasmussen explores the nexus of climate change, retreating glaciers, and conservation landscapes in the context of Pastoruri Glacier in Peru’s Huascarán National Park. As one of the most threatened tropical glaciers in the high Andes, Pastoruri has generated significant media coverage for its rapid retreat, which has involved the glacier losing over half of its size over a period of twenty years, according to reports from The Guardian and Reuters. As Pastoruri Glacier has been reduced to two quickly vanishing patches of ice, tourism in Huascarán National Park has also dwindled from over 100,000 visitors a year in its heyday of the 1990s to only 34,000 reported in 2012.

In response to both the deterioration of the physical landscape and paying visitors, park administrators developed a tourist and educational facility in 2013 known as the Route of Climate Change. The initiative, which includes a “Climate Change Trail,” highlights the dangers of climate change in an effort to boost declining tourist numbers. By presenting the glacier as an endangered species of the growing market of last-chance tourism, the park showcases Pastoruri’s decline as a public spectacle to generate conservation outcomes in other parts of the park. However, like similar conservation initiatives, the project in Huascarán National Park was launched without intensive community engagement.

To explore this issue, Rasmussen collected 48 interviews in Peru during ethnographic fieldwork that began in 2014. These interviews add an anthropological framework to his research in order to understand the unique, often tense relationship between the local communities and protected areas. One community Rasmussen visited extensively during his fieldwork was Catac, located just inside the park boundaries. Rasmussen shared with GlacierHub how his article “contributes to enhancing our understanding of these rather unstable arrangements of consent and contestation in conservation encounters.” In the article, he highlights three issues as complicating conservation efforts in the national park: livestock, infrastructure, and tourism revenues. Because park officials considered the refurbishing project to be purely infrastructural, it did not require community engagement.

Environmental historian Mark Carey told GlacierHub that Rasmussen’s article shows “the economic aspects of glacier loss, when tourists stop visiting a place once the ice is gone or where locals and park administrators subsequently develop incentives for tourists to come back and see the marked impacts of glacier retreat.” He added that “glacier retreat generates challenging policy problems that confound conservation objectives and force changes in tourist experiences and local livelihoods that depend on that tourism.”

Regarding the role of conservation in the Anthropocene, Rasmussen said, “I think conservation is good to think about when we want to try to understand the ways in which climate change acts both as a force which changes the physical appearance of landscapes and as an idea which challenges our understanding of the future.”

Image of Pastoruri Glacier with tourists (Source: Guillaume Weill/Flickr).

The concept of protected area management, and conservation initiatives in general, is heavily imbued with power dynamics and colonialism. Rasmussen states in the article, “Because they are the outcomes of Westernized visions of the relationship between nature and culture, protected areas are important sites for understanding how notions of the Anthropocene come to reshape ideas about the future of glaciated landscapes.”

The historical production of protected areas came from the constructed sharp distinction between human and nature as well as civilization and wilderness, also a product of Western conception that often forgets or ignores voices of the local.

In the Anthropocene, protected areas, particularly those with glaciers, can no longer represent a fixed time and space created by scientists for conservation purposes. Glaciers, like Pastoruri, disrupt the social imagination of an unchanging locale untainted by human intervention. In this modern era signaling progression, climate change presents a destructive alternative, filled with irreversible changes and a future of uncertainty.

The initiative in Huascarán National Park represents a new global consciousness that is forming around the role that humans will play in shaping the future of the planet and around the importance that protected areas will take on in new arrangements in a new era. “Rasmussen demonstrates how glacier loss is more than just about ice, or even water.  Managing a dynamic glacierized landscape rapidly changing under climate change — and ensuring water supplies for irrigation and livestock pastures in downstream communities — all involve politics, social relations, economics and livelihoods, and cultural values,” Carey told GlacierHub. “We must turn our attention beyond the ice, in other words, to study and understand the challenges that communities, conservationists, policy makers, and tourists all face.”

Conservation is still linked to modern social imaginations, but the creation of the Climate Change Route on the Pastoruri Glacier in Peru’s Huascarán National Park implies a shift in the social imagination that reconsiders the presentation and construction of protected areas. With glaciers visually symbolizing the interconnectedness of humans and the rest of the environment, this step forward may better include the often neglected voices of the local communities in shaping their lives.

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Disappearing Ice and Invisible People

Repeat photography of Taboche, Khumbu, Nepal. Top image, 1950s (Source: E. Schneider, courtesy of A. Byers). Bottom image, 2012 (Source: R. Garrard).

People and communities in mountain regions that depend upon glacier resources are directly affected by climate change, suffering the most from impacts of limited water resources, outburst flooding, and changes to agriculture and the economy. Repeat photography showing before and after pictures of specific glaciers as they retreat has been a useful tool to document climate change, from illustrating how glaciers move and melt to how parts of the ice break off. It has enabled humans to gain a better understanding of these important glacial changes and the human impact on the environment. However, repeat photography does not capture local societal impacts well, according to research published in “Beyond Images of Melting Ice: Hidden Histories of People, Place, and Time in Repeat Photography of Glaciers,’’ a recent book chapter by Rodney Garrard and Mark Carey.

The authors discuss the limitations of repeat photography, a form of photography that compares historical and recent photographs to find changes within a landscape, and how it fails to provide a complete perspective of glacier retreat. The photographs do not typically incorporate the people and culture connected to the glaciers, for example, and depict climate change rather uniformly across the world, lacking the ability to show the variety of glacier change issues. While repeat photography can be useful in several ways, it is important to note what it is not capable of capturing: the greater perspective that is often quite more complex. 

Why do we need to capture the societal context, the culture and the stories of the people? And why is it important to point out what repeat photography doesn’t capture today? To date, the common tendency of most repeat photography of glaciers has been to vividly present glacier melt and over simplify downstream impacts, which is actually a form of environmental determinism, Garrard explained to GlacierHub. “Generally, there is no portrayal or even recognition of local people and factors that create differential vulnerability to glacier hazards or climate change,” he said. “While repeat photography can be a useful method to chronicle glacier recession by providing insight into key aspects of glacier dynamics, corroborate results from other glacier studies, and provide a greater historical reach and vividly display these changes for diverse audiences, it can simultaneously yield misinformation by generalizing glacier retreat and providing simplistic deterministic causalities, thereby creating its own narratives about glaciers (i.e., loss), which in turn influence scientific assessments, public perceptions, and government policies.’’

Sagarmatha National Park, 2013 (Source: Thomas Fuhrmann).

The chapter focuses on four case studies to illustrate the limitations of repeat photography as a lens to examine climate impacts: Aletsch Glacier in Switzerland, Grinnell Glacier in the United States, Glacial Lake Palcacocha in Peru, and Khumbu (Mt. Everest region) in Nepal. Garrard and Carey examine how repeat photographs fail to include “hidden histories of people, places, knowledge, vulnerability, and the ever-evolving politics of glacier representation.” The four case studies provide evidence about how certain areas can be more complex than repeat photography can capture.

The first case study of Swiss Alps Jungfrau-Aletsch, for example, is one region where repeat photography has provided knowledge about glaciers and their dramatic retreat since the end of the Little Ice Age. However, the repeat images do not include the societal context and economic impact of this glacier retreat. Likewise, repeat photography at Grinnell Glacier in Glacier National Park in the United States has provided information and understanding of glacier loss in the park but has failed to capture the impacts on local livelihoods.

Peru’s Lake Palcacocha, located in the Cordillera Blanca mountain range, is an important resource to a quarter million people who rely on glacier runoff for irrigation and domestic water use. Changes in accessibility to glacier runoff leads to challenges in water supply, irrigated agriculture, and hydroelectricity generation. Other negative impacts include the dangers associated with glacial lake outburst floods. Since 1941, for example, about 15,000 people have lost their lives in the Cordillera Blanca mountain range due to these floods. Yet, there is no way to translate these impacts through repeat photography.

Similarly, while repeat photography has been helpful in revealing the increase in glacial lakes at Sagarmatha (Mt. Everest) National Park in Nepal, this region is also threatened by glacial lake outburst floods that can cause damage to the nearby communities. There are over 4,000 residents located in the Sagarmatha National Park area, and their vulnerability cannot be fully expressed through repeat photography.

USGS Repeat Photography Project: Grinnell Glacier at Glacier National Park, MT. From the left: Image one, 1981 (Source: Carl Key); Image two, 1998 (Source: Dan Fagre); Image three, 2009 (Source: Lindsey Bengtson).

Carey told GlacierHub, “When we see these repeated photographs, we lament the lost ice, but mainly through a tourism, alpine recreation, cruise ship lens. The photographs appeal to the urban, middle-class, environmentalist sensibility of lost landscape in a national park or a distant peak. But there are no local people, no residents dying in glacial lake outburst floods or living with anxiety about avalanches or worrying about dwindling water supplies or struggling to find jobs, access health care, or send their children to school.’’ 

In other words, repeat photography obscures social and environmental justice. It leaves out key issues playing out below most of the world’s mountain glaciers, such as inequality and injustice, uneven vulnerability to hydrologic change and glacier hazards, the politics of water allocation, the cultural significance of ice, and the political economy of energy regimes and industrial irrigation dependent on glacier runoff, Carey added.

Thus, it is important to understand the limitations of repeat photography and capture the societal context, culture, and stories of the local people. To do this, Garrard offers three tenants of a good repeat photography study: that the method is contextualized, systematic and combined with GIS/RS [Geographical Information System/Remote Sensing] methods as a form of triangulation. The authors conclude, “In terms of the larger picture, this chapter aspires to be an initial step in influencing current repeat photography practices toward broader participation from communities affected.”  

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Palcacocha Icefalls Demonstrate Hazard Vulnerabilities in Peru

Recent Calving Events at Lake Palcacocha

Glacier front subject to calving, Lake Palcacocha (source: Jeff Kargel).

In the last week, calving events at Lake Palcacocha in the Peruvian Andes released masses of ice from a glacier on Mount Pucaranra. The ice fell into the lake, sending waves across the lake that destroyed infrastructure designed to prevent dangerous outburst floods. Fortunately, the waves were not high enough to overtop the moraine dam and send floodwaters downstream, where they could have taken many lives and damaged urban infrastructure. A glacial lake outburst flood from Palcacocha devastated Huaraz, the largest city in the region, in 1941, killing about 5,000 people. Other, more recent, glacier floods in the region have also been very destructive.

Marco Zapata, the director of glacier research at INAIGEM, the Peruvian National Institute of Research on Glaciers and Mountain Ecosystems, spoke about the events recently in a press conference reported in the Peruvian daily El Comercio. A Spanish-language video of the full press conference is available online.

Pucaranra Glacier, Lake Palcacocha, and syphons at the moraine (source: INDECI).

Zapata indicated that the calving event occurred around 8 p.m. on May 31. The resulting waves, three meters in height, were strong enough to move and damage ten large pipes, rendering them inoperable. These pipes, known locally as “syphons,” are designed to draw water from the lake at times when its level is high; in this way, they were thought to reduce flood risk significantly. They had been a point of local pride, seen as a successful application of modern technology to protect against the dangers to which the region has long been subject.

Zapata mentioned that the waves also destroyed several gauges and a sensor which measures lake levels. And the event was not an isolated one, at least according to a regional newspaper, which reported a second calving event at 5:40 a.m. on June 2.

Syphons in operation, releasing water, before recent icefalls (source: Facebook/Vision Informativa Huaraz).

Representatives of INAIGEM and two other organizations, the National Water Authority and the local municipality of Independencia, visited the lake a few days later. They found that the workers on Pucarthe site had restored two of the drainage pipes. These officials anticipated that the other eight will soon be functional.  Zapata and the other authorities called for increased investment in infrastructure at the lake to reduce the risks of a flood. They estimated that an expenditure of US $6 million would prevent about $2.5 billion in potential damages, including a hydroelectric plant and irrigation facilities on Peru’s desert coast; it would also protect the lives of the 50,000 people who live in the potential flood zone.

The Causes of the Calving Events

These events were not entirely unexpected. Marcelo Somos Valenzuela, a postdoctoral fellow at the Northeast Climate Science Center at the University of Massachusetts, is the lead author of a study, published last year in the journal Hydrology and Earth System Sciences, which concluded “there is consensus among local authorities, scientists and specialists that Lake Palcacocha represents a glacier lake outburst flood hazard with potentially high destructive impact on Huaraz.” This paper also stated that a “small avalanche” like the ones that recently occurred are “the highest likelihood event” and that they would “produce significantly less inundation.”  Somos Valenzuela wrote to GlacierHub, “There are empirical models and hydrodynamic models which provide estimates of the height of the wave in the lake… In this case, it seems that the ice-fall was small, and 3 meters is a reasonable estimate of the wave height.”

Workers inspecting syphons at Palcacocha (source: INDECI).

Moreover, several sources indicated high risks at this time of year. Noah Walker-Crawford, an anthropologist at the University of Manchester, spoke recently with the workers at the drainage site at the lake. He wrote to GlacierHub, “According to the people who work at the lake, the icefalls were likely due to unusually strong fluctuations between cold nights and warm days.” He mentioned that they said “there is a block of ice that is ready to fall, but we hope that that won’t happen.”

Jeff Kargel, a planetary scientist at the University of Arizona, told GlacierHub that both calving events and avalanches at Palcacocha “dump energy into the lake, and if they are large and sudden enough, a big wave can form. As with other more classical tsunamis, the shoaling in Palcacocha toward the south end of the lake— where the syphons are— can cause a relatively small displacement wave to build up to a much larger size when it nears the shore. Avalanches and calving events are frequent occurrences at this lake, and both should be especially active in the late May-July period, which tends to be the dry season, hence mainly sunny, thus allowing high solar radiation. The air temperature doesn’t vary much throughout the year, this being deep into the tropics, so variations in sunny versus cloudy days are the main seasons.”

Weather data at Palcacocha, May 2017 (source: INAIGEM).

The weather data indicate some warm days in May at Palcacocha. The data also demonstrate that May had less rain than usual, particularly toward the end of the month. Such dry weather is typically associated with less cloud cover, supporting Kargel’s suggestion and a report in a regional newspaper, Ancash Noticias, which stated that “intense solar radiation” in recent weeks had been the cause of the calving events. The data also support the observations of the local residents about the temperature fluctuations between day and night, since cloudless nights in this region are colder than ones with overcast skies.

Responses to the Calving Events

What can be done to protect Huaraz and neighboring communities from floods, now that the syphons are damaged? Mark Carey gave a long-term view to this question. “Palcacocha has its history of death, destruction, and near misses,” he wrote to GlacierHub. “The issue is partially one of climate change and ever-shrinking glaciers that have caused the lake to expand and fill with more water, creating a hazard waiting to morph into a disaster if Palcacocha’s dam ruptures. Avalanches provide the trigger to help destroy dams.” Referring to Peruvian activities, starting in the 1940s, to lower the lake level and to reinforce the moraine, he added, “The story is also one of engineering and technology. Since the 1990s, funds and political support for actual glacial lake engineering projects have been extremely limited. Now we have regular declarations of states of emergency at Palcacocha, but no engineering projects to provide a more long-term solution.” He also pointed to the need for “an early warning system, and… educational programs to train the population how to respond in the event of an outburst flood or alarm system.”

Workers repairing damaged syphons, Lake Palcacocha (source: Facebook/Municipalidad Distrital de Independencia).

It might be thought that the damage to the syphons would generate support for such solutions. However, obstacles still limit effective responses. Barbara Frazer, a journalist based in Peru for many years, offered a note of concern, linking these events with other disasters in Peru. She told GlacierHub, “Peru’s response to natural disasters is improving, but the country still clearly lags in prevention. The most recent flooding on the coast was an extreme reminder, but every year, there are also landslides on the Central Highway, and children die of pneumonia during the cold snaps high in the Andes. And every year, there’s an emergency response, but little or no long-range planning. Part of that is due to the way responsibilities and budgets are divided among the various levels of government, part to turnover of government staff, and part simply to a lack of a culture of prevention and planning.”

A recent online exchange in Huaraz shows awareness in the region of these issues raised by Carey and Frazer. Most discussants call for greater investment in infrastructure to protect the areas below Palcacocha. However, others suggest that self-interested government agencies play up the risk in order to increase their budgets, which they will divert to personal ends. A scientist, Sonfia González, commented that the regional government lacks the skills needed to manage risks. Others expressed a concern that publicizing the risks would harm the region by reducing tourism. These disagreements point to a lack of confidence, at least on the part of some local residents, in the agencies whose task it is to protect them from natural hazards.

The calving events confirmed scientific research in the area. They also showed the weakness of the existing infrastructure, designed to protect the region from floods. And the discussions in Huaraz show a second, equally serious deficit: the limits of the trust between society, experts, and public agencies, even in ones of the areas of the world most familiar with glacier risks.

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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.

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