Kiwi Glacier is one of the longest glacier in British Columbia. Located in the Cariboo Mountains, this glacier is 9 kilometers long and drains into a growing lack near the headwaters of the Fraser River, the longest river in British Columbia.
According to an article on AGU100 Blogosphere, this glacier has retreated about 700 meters from 1985-2015. Scientists have found that the proglacial lake has grown significantly during that period, from 700-800 meters long to 1400-1500 meters long today. Author Mauri Pelto wrote that since the lower 300 meters of the glacier is flat, the lake will at least extend that far with increased melting.
Check out this video below by Ben Pelto, PhD student at the University of Northern British Columbia. Hundreds of icebergs of all shapes and sizes can be seen drifting on Kiwi’s lake.
Here we examine three Ausangate Glaciers in Peru, which descend south from the Nevado Ausangate group of peaks in the Cordillera Vilcanota. A circumnavigation trek around Nevado Ausangate is a favorite for visitors to the Machu Picchu area.
The glaciers are just west of Laguna Sibinacocha, and drain into the Rio Vilcanota. Retreat of glaciers in the Cordillera Vilcanota has been rapid since 1975, Veettil et al (2017) noted that ~80 percent of glaciated area below 5,000 meters was lost from 1975-2015, and glacier area overall area had declined 48 percent. Henshaw and Bookhagen (2014) observed that from 1988-2010, glacial areas in the Cordillera Vilcanota declined annually by ~ 1 percent per year.
In 1995 the three glaciers all terminate in incipient proglacial lakes. The terminus of #3 is debris covered. By 2000 each of the glaciers is still terminating in an expanding proglacial lake. Glacier #1 and #2 have developed to a size of ~0.1 square kilometers. Glacier #3 still shows limited lake development.
By 2018 Glacier #1 has retreated 450 m and is now separated from the lake. Glacier #2 has retreated 400 m and no longer reaches the lake. Glacier #3 is still in contact with the lake which still has debris covered stagnant ice covering a portion of the basin. This lake has an area of 0.13 square kilometers, and could reach an area of ~0.2 square kilometers depending on debris cover thickness.
The terminus of each glacier has retreated above 5,000 m since 1995. The glaciers each have extensive crevassing and maintains a snow covered accumulation zone, indicating they can survive current climate. Veettil et al (2017) noted that glacier area above 5,300 m was relative stable, for Ausangate Glaciers the area above 5,200 m is in the accumulation zone and has been relatively stable.
The formation of new lakes and the retreat from proglacial lakes has been a common occurrence in recent decades for Andean glaciers in Peru such as Manon Glacier and Soranano Glacier. The key role of glaciers to runoff is illustrated by the fact that 77 percent of lakes connected to a glacier watershed have maintained the same area or expanded, while 42 percent of lakes not connected to a glacier watershed have declined in area, according to Henshaw and Bookhagen (2014). The Ausangate Glaciers supply runoff to the Machupicchu Hydroelectric Power Plant managed by EGEMSA, which has an operating capacity of 90 megawatts. The Vilcanota River becomes the Urubamba River further downstream.
This article was originally published on the American Geophysical Union blog From a Glacier’s Perspective.
In the northwest reaches of the Himalayas, most glaciers, with a few exceptions in the Karakorum, are showing signs of rapid retreat due to climate change. With long-term climate projections indicating the rise of local minimum temperatures by over 4 degrees Celsius above pre-industrial levels by 2100, the formation of glacial lakes is predicted as the glaciers melt, which could, in turn, have serious socio-environmental impacts.
One glacier already under threat, the Drang Drung, located in the Zanskar region of Jammu and Kashmir, is the focus of a recent study published by Irfan Rashid and Ulfat Majeed in Environmental Earth Sciences. It has shrunk over a seventh of its size in the last 46 years from 1971 to 2017. Using the latest earth observation data, Rashid and Majeed discovered the formation of a potential proglacial lake that began in 2008 and has been growing exponentially since 2014. In fact, within the last four years, the rate of retreat at the snout of the glacier appears to have “radically accelerated,” the authors note.
Tucked in a high-altitude, cold, and arid region, the Drang Drung glacier is a massive ice glacier at a whopping length of 23.3 kilometers, almost 15 miles long. Its runoff contributes as a major source of the Zanskar River, a tributary of the mighty Indus River. Additionally, the glaciers of the region play a crucial role in sustaining the area’s economy and energy supply.
But, to date, analysis on the evolution of glacial lakes and their hazardous potential in the northwest Himalayan region is limited. “Formation and behavior of proglacial lakes over the Jammu and Kashmir region have not been studied in much detail, and hence this region remains a data void,” Rashid explained to GlacierHub.
Despite studies in recent years to account for glacial recession and catalog the formation of glacial lakes in the Himalayas as a whole, data on glacial lake evolution, mass balance, snow cover dynamics, and other factors remain scanty. The study sought to provide a more comprehensive assessment of changes in the Drang Drung area. The dangerously high retreat rate in India’s Kashmir compared to other high-altitude glacierized regions in Asia indicates with high probability that this substantial home to glaciers could be lost before the end of the century, according to the article.
With other related implications in mind like streamflows, hydropower capabilities, and tourism, the study highlighted the importance of evaluating the regional changes to the water resources so that “policymakers are equipped with scientifically robust knowledge that will help in framing policies aimed to sustain the ever depleting water resources in the region.”
Toward this aim, Rashid and Majeed used a Glacier Bed Topography (GlabTop) model to estimate Drang Drung’s glacial thickness and glacier bed overdeepenings (characteristics of valleys and basins eroded by glaciers).
“These overdeepenings in the glacier bed provide an idea about the likelihood of formation of proglacial lakes in the future given the retreating behavior of glaciers,” said Rashid. Being able to input meteorological and climate projections, the researchers were able to simulate what portions of the glacier have the potential to hold water and form lakes as the glacier retreats in upcoming years.
Their conclusions were alarming. Since 1971, the glacier has receded a total of over 925 meters, the length of eight Olympic-sized soccer fields stretched out together. Over the past 46 years, the team distinguished three retreat rates: from 1971 to 2000, the glacier retreated at 22.76 meters a year; between 2000 and 2014, the rate slowed to 6.07 meters a year; and since 2014, the pace accelerated rapidly to 60 meters a year, a length just short of two NBA-size basketball courts.
In terms of the new lake, the team’s assessment revealed that the lake’s rapid growth has a potential peak discharge capacity between 2,343 and 2,667 cubic meters of water per second. For a bit of context on this capacity, in 2013, the outburst of the Chorabari lake in Kedarnath (a devastating flood that killed more than 6,000 people and destroyed critical infrastructure including 30 hydropower plants) released a peak discharge of only 783 cubic meters a second. This could mean that the burst of this new moraine-dammed proglacial lake at Drang Drung has the potential to release 3.5 times more discharge than the fatal 2013 outburst, increasing the vulnerability of communities living downstream.
On top of this finding, another portion of the team’s analysis indicated that temperature warming under current projections could lead to the formation of up to 76 new lakes in the region, although this remains entirely dependent of the future retreating behavior of Drang Drung. In addition, with a massive storage capacity following melting, the potential peak discharge rates were estimated to be at a whopping 35,000 to 48,000 cubic meters of water per second.
Despite the increased vulnerability discovered by the researchers, Rashid is unaware of any disaster risk preparedness initiatives to support the vulnerable communities.
“I do not think the communities have been sensitized with the implications of proglacial lakes and their vulnerability to GLOFs [glacial lake outburst floods],” Rashid told GlacierHub. “Since no such disaster has been reported in the regions, the policymakers seem to be in deep slumber. There are at least four such lakes that have constantly been growing in size since the past two decades in the Zanskar region only, and nobody seems to bother about it. I think the perception and response could be altogether different in case, and God forbid, a GLOF strikes the region.”
For the sake of the surrounding communities, the authors hope a major disaster isn’t the first motivator to get policymakers to discuss the necessary warning systems and other measures to protect the local people against the rising risks of climate change.
Glaciers around the world are making headlines for their rapid retreat due to warming. Unlike some of these glaciers, however, dry valley glaciers, while accumulating only about 10 cm of snow annually, are neither retreating nor warming. Sarah Fortner, a geochemistry professor at Wittenberg University in Ohio, examined the meltwater of Canada Glacier, a dry valley glacier located in the Taylor Valley of Antarctica, and published a paper focused on two of its proglacial streams, Anderson Creek and Canada Stream.
Melting of glaciers develops an important part of a glacier’s anatomy known as “supraglacial streams,” which are conduits of water on top of glaciers. These supraglacial streams often become a source of water for “proglacial streams,” like the Anderson Creek and Canada Stream, narrow channels of rivers that issue from glaciers supply water to lakes located below the glaciers.
Fortner studied the meltwater of Canada Glacier during the 2001 to 2002 austral summer in the southern hemisphere (from November to March) and the contribution of the proglacial stream and glacial surface to water in Lake Hoare, which is located in front of Canada Glacier.
In her study, Fortner determines the crucial role of the wind in redistributing the geochemistry of the glacial surface as well as the two proglacial streams. By looking at the geochemistry of the two proglacial streams and the role of the wind in bringing valley sediments to the supraglacial and ultimately proglacial streams, Fortner found that the glaciers that contributed to the proglacial lakes are not dilute like glacier snow.
Contrary to expectations, the chemistry between the two streams was quite different. “While they are roughly five miles apart, they were very different,” she told GlacierHub. “Located on the east side of the glacier, Canada Stream was teaming with life, with multiple mosses, lichen, algae, and invertebrates. If you were to press your hand into these, it would feel like a sponge. On the west side of the glacier, Anderson Creek looks barren in comparison. There is life in the stream, but not as abundant or diverse as the Canada Stream.”
In an attempt to find the source of the difference, Fortner and a team of scientists sampled water from supraglacial channels with high discharge for chemical analysis. Through this analysis, Fortner aimed to map the evolution of the chemicals in the meltwater at Canada Glacier from unmelted glacier snow to supraglacial streams to proglacial streams and finally to Lake Hoare located in front of the glacier.
With the chemical mass balance analysis of the samples from the glacier, Fortner first wanted to see whether the chemical composition of the supraglacial stream would be diluted like the unmelted glacier snow, their primary precipitation. According to Fortner, unmelted glacier snow would naturally be very dilute, with a low concentration of any chemical solute, and we would expect the same level of chemical concentration from the supraglacial streams, located on top of the glacier body itself and created as a result of glacier snow melting. However, she found that supraglacial streams were rich in major ions like calcium, sodium, and sulfate.
“This begins to highlight the importance of wind-blown sediment as control of water chemistry in these Antarctic ecosystems,” Fortner said.
In her paper, she explains that the strong west to east Föhn wind (Foehn wind), a parcel of dry and warm air moving down the lee (downwind side) of the mountain, brought sediments from the floor of Taylor Valley, abundant with carbonate ( CO3(2-)) and gypsum (CaH4O6S) minerals, which are the sources of the high calcium (Ca2+) and sulfate ion (SO2-4) found in the supraglacial streams. In short, the wind delivered sediment that influenced the chemistry of the streams on the surface of the glacier.
“Both sides of the valley floor contributed to the sediment received on the glacier surface which explained major chemical differences found in supraglacial and proglacial streams versus the original unmelted snow. It is also clear that the Föhn wind coming off of the ice sheet had the greatest influence on depositing chemistry,” Fortner explained.
Furthermore, the west to the east direction of the wind causes a difference in chemical composition between the proglacial streams in the western and eastern sides of Canada Glacier, preferentially depositing more sulfate in the western proglacial streams (Anderson Creek) than in the eastern proglacial streams (Canada Stream).
“As a result of the west to east wind, supraglacial streams flowing into Anderson Creek have much higher concentrations of both calcium and sulfate than supraglacial streams flowing into Canada Stream,” Fortner explained.
The chemical deliveries from the stream channel to the proglacial lake is crucial to examine, as Anderson Creek contributes over 40 percent of the water to Lake Hoare, the final recipient of the meltwater from Canada Glacier, during the low-melt season. However, Fortner said it is just as important to examine the chemical deliveries from the glacial surface (direct runoff).
“While one would think streams would deliver far more chemistry, as glaciers and their direct runoff are typically dilute, glacier surface can be just as important source of chemistry because of the low accumulation and wind delivered sediment,” she added.
Dry valley glaciers are unique in that the glacier surface is an important contributor of chemistry to downstream ecosystems. Unlike many other glaciers, it isn’t just about chemistry from stream channels, but also about glacier surfaces. If more melt continues in response to the wind, this could result in potential changes in the chemical delivery into Lake Hoare. Furthermore, such changes can extend to the continental outline of Antarctica into Ross Sea, the southern extension of the Pacific Ocean.
From Earth Systems Dynamics: “Largely depending on the meltwater from the Hindukush–Karakoram–Himalaya, withdrawals from the upper Indus Basin (UIB) contribute half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and domestic use, and hydropower generation. Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing. Against this background, this study assesses the trends in maximum, minimum and mean temperatures, diurnal temperature range and precipitation from 18 stations (1250–4500 m a.s.l.) for their overlapping period of record (1995–2012) and, separately, from six stations of their long-term record (1961–2012).”
Learn more about climate trends and runoff of the upper Indus Basin here.
Proglacial Lake Cores from Southeast Greenland
From Quaternary Science Reviews: “Accelerating ice loss during recent years has made the Greenland Ice Sheet one of the largest single contributors to global sea level rise, accounting for 0.5 of the total 3.2 mm yr−1. This loss is predicted to continue and will most likely increase in the future as a consequence of global warming. However, the sensitivity of glaciers and ice caps (GICs) in Greenland to prolonged warm periods is less well constrained and geological records documenting the long-term glacial history are needed to put recent observations into a broader perspective. Here we report the results from three proglacial lakes where fluctuations in local glaciers located at different altitudes in Kobbefjord, southwest Greenland have been recorded.”
Read more about three proglacial lake records from Kobbefjord, southeast Greenland here.
Modeling Stream Habitats and Salmon Genetic Diversity
From Journal of Fish Biology: “Measures of genetic diversity within and among populations and historical geomorphological data on stream landscapes were used in model simulations based on approximate Bayesian computation (ABC) to examine hypotheses of the relative importance of stream features (geomorphology and age) associated with colonization events and gene flow for coho salmon Oncorhynchus kisutch breeding in recently deglaciated streams (50–240 years b.p.) in Glacier Bay National Park (GBNP), Alaska. Population estimates of genetic diversity including heterozygosity and allelic richness declined significantly and monotonically from the oldest and largest to youngest and smallest GBNP streams.”
Discover more about the genetic diversity of coho salmonhere
Understanding the nature of glacial changes has become increasingly important as anthropogenic climate change alters their pace and extent. A new study published in The Cryosphere Discussions journal shows how Unmanned Aerial Vehicles (UAVs), commonly known as drones, can be used to do this in a relatively cheap, safe and accurate way. The study represents the first time a drone has been used to study a high-altitude tropical Andean glacier, offering insight into melt rates and glacial lake outburst flood (GLOF) hazards in Peru.
The study was carried out by Oliver Wigmore and Bryan Mark, from the University of Colorado Boulder and Ohio State University respectively. It is part of a larger project aimed at understanding how climate change is affecting the hydrology of the region and how locals are adapting to these changes.
The researchers used a custom-built hexa-multirotor drone (a drone with propellers on six arms) that weighed about 2kg to study changes in Llaca Glacier in the central Cordillera Blanca of the Peruvian Andes.
Llaca, one of more than 700 glaciers in the Cordillera Blanca, was chosen for both logistical and scientific reasons. It covers an area of about 4.68 square kilometers in Huascaran National Park and spans an altitudinal range of about 6000 to 4500 meters above sea level. Like other glaciers within the Cordillera Blanca, it has been retreating rapidly because of anthropogenic climate change.
To obtain footage, the researchers had to drive three hours on a winding, bumpy road from the nearest town, located about 10km away from the valley. “This was followed by a half–hour hike to the glacier,” Wigmore stated.
To overcome some of the challenges of working in a remote, high-altitude region, the drone was custom-built using parts bought directly from manufacturers. In this case, a base was bought from a manufacturer. “I modified it by making the arms longer, lightening it with carbon fiber parts, and adding features like a GPS, sensor systems, infrared and thermal cameras, and other parts required for mapping,” Wigmore shared.
Building their own drone allowed the researchers to repair it or replace parts when necessary, as sending it off to be repaired while in the field was not possible. It also allowed them to customize the drone to their needs.
“No commercial manufacturers could promise that our equipment would work above an altitude of about 3000m, which is well below the glacier,” Wigmore said.
Using drones to study glaciers has advantages over conventional methods in terms of access to glaciers and spatial and temporal resolutions of data. These advantages have been further enhanced by hardware and software developments, which have made drones a relatively cheap, safe and accurate remote sensing method for studying glaciers at a finer scale. For example, Wigmore can build a UAV for about $4000, compared to the high cost of airplanes and satellites also used in remote sensing.
Wigmore and his team carried out aerial surveys of the glacier tongue (a long, narrow sheet of ice extended out from the end of the glacier) and the proglacial lake system (immediately beyond the margin of the glacier) in July 2014 and 2015. The drone was flown about 100 meters above the ice while hundreds of overlapping pictures were taken to provide 3-D images and depth perception.
High resolution (<5cm) Digital Elevation Models (DEMs) and orthomosaics (mosaics photographs that have been geometrically corrected to obtain a uniform scale) were produced, revealing highly heterogeneous patterns of change across the glacier and the lake. The data also revealed that about 156,000 cubic meters of ice were lost within the study period.
The images revealed, for example, that the location of exposed cliffs and surface melt water ponds serve as primary controls on melt rates in the glacier tongue. Exposed cliffs lack the insulation of thick debris that are common on the glacier tongue, while ponds are less reflective than ice and absorb more solar radiation, causing higher melt rates.
The thickness of debris layers on the glacier constitute a secondary control. Thicker layers (often over 1m deep) provide insulation from solar radiation, while thinner layers increase the absorptivity of the surface to solar radiation.
The study also found that the upper section of the proglacial lake contains sections of glacier ice which are still melting. This suggests that the extent and depth of the lower section of the lake will increase as the ice continues to melt. This could increase the risk of GLOF, as expansion of the lake will bring it closer to the steep headwalls of the valley, which are potential locations for avalanche and rockfall debris.
Wigmore’s research is part of a series of larger projects still under publication that involve using drones to study glaciers, wetlands and proglacial meadows in the region. The results contribute to our understanding of hydro-social changes in the Cordillera Blanca, and how they can be managed.
Find out more about drone research here, or learn about Wigmore’s other research here.