Photo Friday: Taku Glacier Is Finally Receding

The Wikipedia page for Taku Glacier needs updating.

Taku Glacier, the deepest and thickest alpine temperate glacier in the world, is no longer the only major glacier advancing in the Juneau Icefield––it is finally receding. Taku, which measures 4,845 feet (1,477 m) and 36 miles (58 km) long, was long heralded as a symbolic holdout to the melt that has most glaciers in retreat.

Taku Glacier on August 20, 2014 (Source: NASA)
Effects of Taku Glacier mass loss is visible at the boundaries between the glacier and river. Image taken on August 9, 2019 (Source: NASA)

Mauri Pelto is a professor of environmental science at Nichols College and director of the North Cascades Glacier Climate Project. “This is a big deal for me because I had this one glacier I could hold on to,” Pelto told NASA. “But not anymore. This makes the score climate change: 250 and alpine glaciers: 0.”

Pelto’s finding was published in the journal Remote Sensing on October 14. The following day GlacierHub published a post by Pelto, “A Two-Century-Long Advance Reversed by Climate Change.”

The determination that Taku has succumbed to the warming climate was made after completing annual end-of-summer snowline measurements. Surface melt is responsible for the glacier’s turnaround, according to Pelto. The Juneau Icefield Research Program has been watching and reporting Taku’s yearly mass balance to the World Glacier Monitoring Service since 1946.

The glacier had been expected to continue advancing through the rest of the century. “To be able to have the transition take place so fast indicates that climate is overriding the natural cycle of advance and retreat that the glacier would normally be going through,” Pelto said.

An entry at the bottom of Taku’s Wikipedia page reads “Taku Glacier was reported to be in retreat as of 2019.” (Source: Wikipedia)

Read More on GlacierHub:

A Two-Century-Long Advance Reversed by Climate Change

What the 2018 State of the Climate Report Says About Alpine Glaciers

Glaciers Account for More Sea Level Rise Than Previously Thought

A Two-Century-Long Advance Reversed by Climate Change

Taku Glacier in 2016 and 2019 Sentinel 2 images. The Hole in the Wall Tributary (HW) is upper right, Taku Glacier main terminus (MT). Yellow line is the 2016 terminus location. The arrows denote locations where thinning is apparent as the area of bare recently exposed bedrock has expanded. A closeup is below. Pink and brown areas between blue ice and yellow line in 2019 indicates retreat.

The Taku Glacier is the largest outlet glacier of the Juneau Icefield in Alaska. Taku Glacier began to advance in the mid-19th century, and this continued throughout the 20th century. At first observation in the 19th century, the glacier was calving in deep water in a fjord. It advanced 5.3 kilometers between 1890 and 1948 moving out of the fjord into the Taku River Valley (See maps below (Pelto and Miller, 1990). At this time calving ceased resulting in positive mass balance without the calving losses. The glacier continued to advance 2.0 km from 1948-2013 (Pelto, 2017). The advance was paralleled by its distributary terminus, Hole in the Wall Glacier. This advance is part of the tidewater glacier cycle (Post and Motyka, 1995), updated model by Brinkerhoff et al (2017). At the minimum extent after a period of retreat the calving front typically ends at a point of constriction in fjord width or depth that limits calving. With time, sedimentation in front of the glacier reduces water depth and calving rate, allowing the glacier to begin to advance. In the case of the Taku Glacier, after a century of advance, the glacier had developed a substantial proglacial outwash and moraine complex that had filled in the fjord, and the glacier was no longer calving. Images below, from 1961 and 1981, illustrate this. This allowed the advance to continue through the rest of the 20th century and into the 21st century. The slowing of the advance in the latter half of the 20th century has been attributed to the impedance of the terminus outwash plain shoal (Post and Motyka, 1995Pelto and Miller, 1990). There is a concave feature near the terminus with an increase in crevassing where the push impacts flow dynamics as seen at black arrow in 1975 and 1998 images below. In 1980’s the Taku Glacier’s accumulation area ratio was still strong enough for Pelto and Miller (1990) to conclude that the Taku Glacier would continue to advance for the remaining decade of the 20th century, which it did.

Beginning in 1946, the Juneau Icefield Research Program began annual mass balance measurements that is the longest in North America. In conjunction with JIRP and its first director Maynard Miller, we compiled and published an annual mass balance record in 1990. From 1990 to the present, in conjunction with JIRP and Chris McNeil, we have continued to compile and publish this annual mass balance record (Pelto et al 2013).  Much of the remarkable data record of JIRP has this month been made accessible to the public, particularly through the efforts of Seth Campbell, JIRP director; Scott McGee, survey team director; and Chris McNeil, mass balance liaison with USGS.

The ELA in 2018 and 2019 in Landsat images, purple dots indicate the record high snowlines for the 1946-2019 period for each year.

Taku Glacier is one of the thickest known alpine temperate glaciers. It has a maximum measured depth of 1,480 meters, and its base is below sea level for 40-45 km above the terminus (Nolan et al 1995). Moytka et al (2006) found that the glacier base was more than 50 m below sea level within 1 km of the terminus and had deepened substantially since 1984. This suggests a very long calving retreat could occur. The glacier had a dominantly positive mass balance of +0.42 m/year from 1946-1988 and a dominantly negative balance since 1989 of  -0.34 m/year (Pelto et al 2013). This has resulted in the cessation of the long term thickening of the glacier. On Taku Glacier, the annual ELA (end of summer snowline altitude) has risen 85 m from the 1946-1988 period to the 1989-2019 period. During the 70+ year annual record the ELA had never exceeded 1,225 m until 2018, when it reached 1,425 m (Pelto, 2018).  In 2019, the ELA again has reached a new maximum of 1,450 m (see above images). Contrast the amount of the glacier above the snowline in 2018 and 2019 to other recent years that had more ordinary negative balances (see Landsat images below).

In 2008 and 2012, JIRP was at the terminus, creating the map below. There was no change at the east and west side of the margin since 2008, with 55 to 115 m of advance closer to the center. The glacier did not advance significantly after 2013 and did not retreat appreciably until 2018. The Taku Glacier cannot escape the result of three decades of mass losses, with the two most negative years of the record being 2018 and 2019. The result of the run of negative mass balances is the end of a 150+ year advance and the beginning of retreat. Sentinel images from 2016 and 2019 of the two main termini Hole in the Wall Glacier (right) and Taku Glacier (left). The yellow arrows indicate thinning and the expansion of a bare rock trimline along the margin of the glacier. The Hole in the Wall terminus has retreated more significantly with an average retreat of about 100 m.  The Taku main terminus has retreated more than 30 m along most of the front.

The retreat is driven by negative balances, mainly by increased surface melt. The equilibrium flow of the Taku Glacier near the long term ELA for the 1950-2005 period was noted by Pelto et al (2008). This occurred during a period of glacier thickening, average profile velocity was 0.5 md-1  (Pelto et al 2008). Since 1988 the glacier has not been thickening near the snowline as mass balance has declined slightly (Pelto et al 2013). The remarkable velocity consistency measured by JIRP surveyors led by Scott McGee each year at profile 4 has continued. It is below this profile that surface ablation has reduced the volume of ice headed to the terminus.

All other outlet glaciers of the Juneau Icefield have been retreating, and are thus consistent with the dominantly negative alpine glacier mass balance that has been observed globally (Pelto 2017).  Now, Taku Glacier joins the group unable to withstand the continued warming temperatures. Of the 250 glaciers I have personally worked on, it is the last one to retreat. That makes the score: climate change 250, alpine glaciers 0.

1890 United States Coast Guard map indicating deep water in the fjord in front of Taku Glacier.
Map of terminus change from Lawrence (1950)
Taku Glacier aerial photograph from US Navy in 1948. Still minor calving on right (east side
Taku Glacier in 1961, photograph indicating calving had ended
This is a view across the glacier accumulation area that until 2018 had always been snow covered at the end of summer (Credit: Pelto).

To see more photos of Taku Glacier, check out the Mauri Pelto’s original post on From a Glacier’s Perspective, a blog published by the American Geophysical Union.

Read more on GlacierHub:

Roundup: Tropical Glaciers, Experimental Cryoconite, and Grand Teton National Park

Making Connections at the 2019 International Mountain Conference

Video of the Week: Melania Trump Pays a Visit to Wyoming’s Grand Teton National Park

US Forest Service Plans to Overhaul Tourism at Mendenhall Glacier

Just a short journey from Alaska’s capital city of Juneau, Mendenhall Glacier is the state’s most popular summer tourist destination, and arguably one of the most accessible glaciers in the world. Located in Tongass National Forest, Mendenhall is one of 38 glaciers that originate from the massive 1,500 square mile Juneau Icefield. From its origin to its terminus at Mendenhall Lake, the glacier stretches some 13.6 miles

A strong tourism industry around  Alaska’s glaciers provides the state with substantial economic benefits. It also gives visitors an opportunity to witness the effects of anthropogenic  climate change. 

Beyond the pristine beauty and temperate summertime weather in Alaska, so-called “last chance tourism” is a huge motivation for visitors, who wish to marvel at immense blocks of blue and white ice as well as Mendenhall’s famous ice caves before they melt. 

Opened in 1962, the Forest Service Visitor Center at Mendenhall Glacier was the very first in the United States. “When this visitor center was built, there were 23,000 visitors per year, and now there’s over 700,000,” James King, a region director for the US Forest Service in Alaska, told the Juneau Empire.

The summer of 2019 is expected to break tourism records for Alaska as a whole, with 1.3 million visitors expected, a 16 percent increase from 2018. Visitorship is expected to continue growing by 2-4 percent per year. 

Current facilities are designed for up to 485,000 visitors per year. The growth in tourists has caused congestion, long waits, and an experience that is less than ideal for visitors to the 6,000 acre Mendenhall Glacier Recreation Area

Robin Bouse, a tourist who visited Mendenhall last month, described the overcrowdedness. “The visitor center was crowded, so crowded that I couldn’t wait to get out of there,” she told GlacierHub. “I came from a cruise ship with about 4,000 passengers aboard and there were four  similar ships in port that day.” 

At its current capacity, the visitor center can only accommodate 4,000 people at a time.  

A panoramic view of Mendenhall Glacier and the surrounding Mendenhall Lake, taken in the summer of 2006 (Source: Mike Keene).

In addition, tourist infrastructure will need to evolve to keep up with climate change. From satellite measurements taken by NASA’s Landsat 5 satellite in 1984 and Landsat 8 in 2013, Mendenhall retreated almost 4,000 feet, or three-quarters of a mile in under 20 years. Mendenhall Lake, which sits right at the terminus, has grown by roughly the same amount.

Another visitor to the glacier, Tim Denham, thought a visual representation of the glacier’s retreat over time would have been a valuable visual to add to the experience. “I think it would have been good to have big 4×4 posts with the years carved into them to show how rapidly it has receded,” he said.

By 2050, the glacier itself will no longer be visible from the huge windows that look out from the Mendenhall Glacier Visitor Center. ”The glacier ice was so beautiful and I felt fortunate to see it,” Bouse said. “It was easy to see that the glacier is retreating from the bare rocks surrounding it.”

Taken from the same perspective as above: Mendenhall Glacier in May 2019. Massive retreat in the 13 years between the two photos is apparent. The photographer, Henry Titzler, noted this day was about 86 degrees Fahrenheit, remembering summer temperatures averaging around 62 degrees during a previous visit in 1979.

From 2016 to 2018, six public meetings were held to develop a plan for revamping the Mendenhall Glacier Recreation Area and Visitor Center. The updated 50-year plan, published by the US Forest Service in February 2019 emphasizes major renovations over the next 10 years. 

The Mendenhall Glacier Master Plan aims to create a sustainable recreation experience that can adjust to variations in glacier features. King from the US Forest Service estimated the project’s price tag at around $80 million

As the glacier continues to retreat, the current viewpoints will become more strained, and visitors with a time limit––such as those who must return to their cruise ships––could subsequently be unable to attain the full experience.

“It was difficult to get up close to the glacier with the few hours I had to spend there, but the distant view was still spectacular enough,” said Bouse. 

Denham similarly noticed the marked appearance of the glacier’s retreat, noting it was “barely visible across the lake. We hiked out a half mile on the trail but we were still too far away to see much.” 

To accommodate increased glacial melt, the new plan proposes to switch from a land-based focus on hiking trails and viewing areas to a more water-based approach, complete with a commercial boat service to take people in small groups right to the terminus of Mendenhall Glacier.

There will also be a smaller mobile visitor center closer to the glacier itself. These new features will fulfill the frequently cited desire of tourists to truly be interactive with the glacier, allowing visitors to “touch the ice.”

Other parts of the proposed plan include more restrooms, a larger theater, and expanding parking availability. New walking trails will increase access to ecosystems newly exposed by the glacier’s retreat, including salmon, bears, and other wildlife. Finally, an additional visitor center will provide amenities such as food, restrooms, and directions, leaving the original building as an educational center and museum. 

Taken together, these alterations could give the visitors a more pleasant and informative stay, showing them the glacier as it is now and as it had been. And it could awaken in them a sense of the urgency of climate change as a pressing issue, whether on vacation or back at home.

Tensions Among Early Glacier Researchers in Alaska

A new study published in the journal Isis details a decades-old conflict between early glacier researchers in Alaska, a conflict that remains relevant today. The controversy, known as the Miller–Beckey dispute, started at the Juneau Icefield in the late 1940s when a scientist-climber named Maynard Miller clashed with fellow mountaineer Friedrich Beckey. Beckey discounted Miller’s scientific research due to Miller’s secondary role as a mountaineer, suggesting that because Miller was a sportsman, he could not also be a serious scientist. The dispute took place at a time when North American glaciology was a nascent geophysical science.

Hikers on the Mendenhall Glacier, Juneau Icefield (Source: Gillfoto/Flickr).

The Background of the Conflict

The Juneau Icefield Research Project (JIRP), which brought both men to the ice, was one of the first programs of glaciology in North America, according to the article’s author, Danielle Inkpen. It was an on-site, long-term study of the Taku glacier, an outlet glacier of the Juneau Icefield. Intensive field observations like those made at JIRP required researchers to live on the ice for extended periods of time. Dangers such as hidden crevasses and snow blindness required the traditional skill set of a mountaineer. As a result, JIRP drew many fieldworkers from elite mountaineering circles. 

Miller, founder and long-time director of JIRP, was one of these early adventurers. Inkpen writes that Miller was a skilled climber, having joined America’s first Mt. Everest expedition in 1963. But he was also an educated scientist who studied geology and glaciology, earning undergraduate and master’s degrees from Harvard and Columbia University, and a Ph.D. from Cambridge University. Miller’s dual roles as both an active mountaineer and scientific researcher prompted his rival Beckey to cast doubt on his scientific credibility. Nicknamed “lone wolf,” Beckey was a legendary American rock climber and an Alpine-style mountaineer. He is known to many from the documentary, “The Legend of Fred Beckey,” for having completed more first ascents than any other North American climber.

JIRP Crew, 1949. Miller is in the middle.(Source: Isis/“The Scientific Life in the Alpine: Recreation and Moral Life in the Field”).

Miller was first introduced to the Alaskan glacier as a member of an expedition which first summited Mount Bertha, led by Bradford Washburn, his geography instructor at Harvard. Miller and Washburn built a sense of camaraderie when they were roped up together during a climb while both part of the Harvard Mountaineering Club (HMC). Later, Washburn recommended Miller as the field assistant for glacier research in Alaska in 1941 with William Field, one of the founders of the HMC and also a leading mountaineer, photographer and geologist in the 1920s with a number of first ascents to his credit. These men all came to glaciology through mountaineering. Miller’s passion for scientific fieldwork in Alaska originated in his desire to explore the climbing potential in southern Alaska.

The Conflict Develops

Miller returned to Alaska in 1947 for JIRP. The project’s primary funder was the Office of Scientific Research and Development of the American military. Inkpen explains that investment in glaciology was made possible by the United States military, which increased expenditures during the Cold War amidst national security concerns. The Polar region was a major geopolitical hotspot at the height of the conflict, and launching missiles from secret bases under ice caps was considered a possibility. Observations of Alaskan glacier fluctuations during this time triggered further investigations into the relationship between glaciers and climate. In order for JIRP to avoid a misunderstanding about their primary commitment to science, it had to keep its professional image as a glacial science organization, Inkpen notes. Other glaciological expeditions at the time, like Snow Cornice, were supported by private funders. As JIRP’s military sponsor said, ‘‘No funds could be provided for mountaineering.”  

As a result of this policy, Miller did no climbing during the first summer of research at Juneau. However, he was reportedly located close to the attractive spire, Devil’s Paw. He also wrote an article about the mountaineering possibilities at Juneau Icefield for HMC’s Bulletin; according to Inkpen, Miller believed that this piece would go unnoticed by his funder. She quotes his article as stating that the 1949 season would bring “many interesting ascents of the magnificent granite and metamorphic rock peaks which protrude out of the ice and snow in this glacial-alpine paradise.”

Fred Beckey ascending rope on an “aid pitch,” North Cascades, n.d. (Source: North Cascades National Park archives).

Miller and Beckey had an unpleasant history before their confrontation in Juneau. Inkpen explains that as climbing partners, they failed to reach the summit of the Nooksack Tower in North Cascades National Park, in Washington State. However, Miller would later try a second time with another team, excluding Beckey. Then, in 1948, when Miller became field leader at the Juneau Icefield, he wrote a letter to Beckey telling him to stay away, Inkpen reports. She further notes that Miller claimed he was afraid that the press attention from Beckey’s first ascent would undermine JIRP’s reputation, especially at a time when the organization needed funding. However, the true purpose of the letter remains unknown. Inkpen indicates that it cannot be ruled out that Miller merged private affairs into public ones, wanting to save the first ascent for himself. Beckey followed Miller’s request for a time, but in 1949 he marched to Juneau unexpectedly and successfully conquered the Devil’s Paw.

The Consequences of the Conflict

Reverberations continued for Beckey and Miller after Beckey wrote to American Alpine Club (AAC) condemning Miller for practicing pseudoscience and using science as a cover for his mountaineering ambitions. Beckey further accused Miller of violating the codes of sharing information with fellow mountaineers. Certain gentlemanly rules inherited from the Victorian golden age of climbing governed first ascent. Using climbing information from other climbers to reach the summit was regarded as improper. Beckey even claimed that Miller had besmirched him and broke his climbing buddy’s arm during a visit. 

Instead of declaring the scientific importance of his research to defend himself and the JIRP, Miller hit back as a mountaineer, reportedly stating, “That is the most unfortunate [and] uncalled for situation that has ever arisen to besmirch the name of the HMC and the AAC.” He asked the mountaineering community to ban Beckey’s actions and questioned Beckey’s integrity for deliberately concealing his climbing routes. As a result, the AAC convened a three-person committee to investigate this Miller-Beckey dispute. According to the article, the committee concluded the matter as an attack on Miller’s professional credibility in order to encourage the club members to work with scientific expeditions. Their judgment had a profound influence on interweaving scientific research with mountaineering, Inkpen reports.

As GlacierHub learned from Erin Pettit, a glaciologist at the University of Alaska who conducts research and teaches at JIRP, the conflict between mountaineers and scientific research is still relevant today. “There certainly is a challenge when ego comes into play,” Pettit said. “If someone on a field team has more of a mountaineering ego, he/she wants to summit a mountain and put the science as a lower priority, that may be their choice. However, if it affects the goals of the entire field research team, then that is an issue. Similarly, a team of mountaineers might have the goal of achieving a new route on a mountain. If one of them is also a scientist and gets too distracted by science to support the goals of the mountaineering team, then the team will suffer.” Teamwork relies on having everyone on board with the goals of the team, she said. This involves each team member knowing what their role is on the team.

In the end, the Miller–Beckey dispute revealed a conflict between scientific and recreational values. It shows how pride and a competitive spirit can undermine the teamwork that is required for new accomplishments in the field, a topic of significance even today.


Photo Friday: Juneau Icefield Expedition

Hands-on experience visiting glaciers is crucial for students pursuing a career in glaciology. The Juneau Icefield Research Program is one of the longest-running glacier research programs with a 70-year history of bringing young people to the glaciers of Alaska and British Columbia. In 1948, Maynard Miller, one of the climbers on America’s first Mt. Everest expedition in 1963, led a group of explorers on a first expedition to Juneau Icefield, which includes some 50 outlet glaciers. Ever since, the program has been leading young students from high school to the graduate level to Juneau Icefield, offering opportunities to conduct field research with faculty and explore various glacial landforms and features.

Students begin their traverse from Juneau, Alaska, making their way up the Coast Mountains of Alaska and British Columbia, Canada. During their expedition, students interact with the other members of the research group and faculty advisers to collect field data and analyze the data in camp sites, where various tools are provided to assist the analysis. They finish their expedition in the small town of Atlin, Canada, where they give presentations about their group research conducted on the icefield. 

Below are some pictures taken by students, staff, and faculty during their time on the Juneau Icefield.

For more information on the Juneau Icefield Research Program, visit

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Northern Lights appeared above the grand junction of Gilkey and Vaughan-Lewis Glaciers (Source: Deirdre Collins).


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Gilkey Trench overlooked from on a nunatak located in the junction of Gilkey and Vaughan-Lewis Glaciers, both tributary glaciers of Juneau Icefield (Source: Deirdre Collins).


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A student from 2016 Juneau Icefield Research Program exploring a crevasse (Source: Lucas Foglia, Deirdre Collins).


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Arête overlooking the Gilkey Glacier (Source: Deirdre Collins).


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Sunset seen from Camp 17, located on a nunatak in Gilkey Glacier (Source: Deirdre Collins).

Roundup: Ice Filing, Seas Falling, Rivers Flooding

This Week’s Roundup: Glaciers are being collected in Antarctica, “quietly transforming the Earth’s surface” and causing floods

A team of scientists, aware of the need to obtain ice cores from threatened glaciers, are working to create a glacier archive bank in Antarctica

From CNRS News:  “By capturing various components of the atmosphere, ice constitutes an invaluable source of information with which to examine our past environment, to analyze climate change, and, above all, to understand our future. Today, the science of ice cores lets us study dozens of chemical components trapped in ice, such as gases, acids, heavy metals, radioactivity, and water isotopes, to name but a few…”

“We plan to store the boxes in containers at a depth of 10 meters below the surface in order to maintain the glacier cores at an ambient temperature of – 54°C. The Antarctic is in fact an immense freezer with an ice sheet up to 4 kilometers thick, and is far removed from everything; in addition, it is not subject to any territorial disputes. The subterranean chamber will be large enough to house samples taken from between 15 and 20 glaciers.”

A lightweight core extractor that will measure glaciers.(Photo courtesy B. JOURDAIN/CNRS PHOTOTHEQUE).
A lightweight core extractor that will measure glaciers.(Photo courtesy B. JOURDAIN/CNRS PHOTOTHEQUE).

Read on here. 

Study finds that ancient melting glaciers are causing sea levels to drop in some places

From Smithsonian Magazine: “But a new study out in the Journal of Geophysical Research shows that in places like Juneau, Alaska, the opposite is happening: sea levels are dropping about half an inch every year. How could this be? The answer lies in a phenomenon of melting glaciers and seesawing weight across the earth called ‘glacial isostatic adjustment.’ You may not know it, but the Last Ice Age is still quietly transforming the Earth’s surface and affecting everything from the length of our days to the topography of our countries.”

A beach in Juneau, Alaska, where glacial isotactic adjustment has prompted sea levels to drop, not rise. (Photo courtesy Joseph, Flickr CC BY-SA).
A beach in Juneau, Alaska, where glacial isotactic adjustment has prompted sea levels to drop, not rise. (Photo courtesy Joseph, Flickr CC BY-SA).

For the full story, click here.

Glacial flood emerges along Iceland’s Skaftá river

From Iceland Magazine: “A small glacial flood is under way in Skaftá river in South Iceland. The Icelandic Met Office (IMO) warns travelers to stay away from the edge of the water as the flood water is carrying with it geothermal gases which can be dangerous….The discharge of Skaftá at Sveinstindur is presently 270 cubic metres per second. The flood is not expected to cause any downstream disruption.”

Outburst floods swept away a bridge and caused other damage in the river last year. (Photo Courtesy Egill/Iceland Mag).
Outburst floods swept away a bridge and caused other damage in the river last year. (Photo Courtesy Egill/Iceland Mag).

Learn more about the flood by reading more here.





Wildfires Melt Glaciers From a Distance

Scientists have begun to trace a link between climate change, an increased number of wildfires and glacier melting.  Particles emitted by wildfires and then deposited on glaciers are thought to darken the ice’s surface, and may lead to more rapid melting.

Natalie Kehrwald, a geologist from the United States Geological Survey (USGS), is currently studying the levels of wildfire particles deposited on the Juneau Icefield in Alaska. Kehrwald and her fellow USGS geologist, Shad O’Neel,  who is tracking the retreat of glaciers in the Juneau Icefield, are working together to document the contributions of wildfires to glacier melting.

Collecting ice cores on the Juneau Icefield (Source: Natalie Kehrwald).

“In the past two to three years there have been huge wildfires [in Alaska]… I am trying to see if there are aerosols being deposited on the Juneau ice field and if they are accelerating the melting,”  said Kehrwald in an interview with GlacierHub.

According to multiple sources, including the University of Alaska Fairbanks and the non-profit research and news organization Climate Central, rising Arctic temperatures are creating longer and more severe wildfire seasons, with larger and more frequent fires.  Kehrwald proposes that an increase in wildfires has led to a greater volume of aerosols, a mixture of carbon and other particles, deposited onto glaciers.  There may be a minor feedback as well. Since glaciers act as large mirrors and keep the planet cooler by reflecting solar energy back into space, the loss of glaciers could also accelerate the rise in temperaturse.

In early August, Kehrwald and O’Neel led a team of student researchers from the Juneau Icefield Training Program into the field, where they gathered ice cores.  They will later analyze these cores for wildfire indicators in a lab.  

Natalie Kehrwald’s team of Juneau Icefield Research Program students (Source: Natalie Kehrwald).

“We take samples from the highest, flattest parts of the glacier in specific locations that are impacted by air masses.  We drill down 7-9 meters, which date back about two to three years,” said Kehrwald, summarizing their trip.

The carbon deposits from wildfires can be grouped into a larger category called black carbon, which have been linked to rapid glacier melting.  Black carbon refers to carbon released from both biomass burning and fossil fuel emissions.  In order to determine whether the carbon on the Juneau Icefield is from wildfires, Kehrwald will look for a specific molecular marker in the ice.  

“It is a sugar called levoglucosan and it is only produced if you burn cellulose at a temperature of about 250 degrees Celsius,” said Kehrwald.  “So if you see high concentrations of that molecule you know the origin is biomass burning, which is generally wildfires but could be a big compilation of household fires.”

A team of Alaskan  firefighters marches down to meet the flames (Source: BLM Alaska Fire Service/Facebook).

Although the Alaskan wildfires occur predominantly in the boreal forest located in a drier region far north of the Juneau Icefield, smoke from wildfires have been known to travel great distances.  The phenomena of darkening glaciers due to particles from wildfires was well documented last year when large wildfires in British Columbia deposited particles on glaciers across the North American Arctic and as far as Greenland.

According to the University of Alaska Fairbanks, three of the top ten largest Alaskan wildfires since 1940 occurred in the last decade.  In 2015, Alaskan wildfires burned over 5 million acres of land.  Alaska’s burnt acreage represented five-sixths of the national total land consumed by wildfires in that year, according to The Washington Post.  The acreage of wildfire burned land in 2015 is second only to the approximately 6.5 million acres burned in 2004.

A 2015 report, The Age of Alaskan Wildfires, produced by non-profit group Climate Central stated that large Arctic wildfires are no longer rare.  

Satellite image showing Alaskan wildfires on June 25, 2015. Actively burning areas are outlined in red. NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team. Caption: NASA/Goddard, Lynn Jenner (Source:

“We found the number and size of areas burnt by large wildfires [in Alaska] is on the rise since the 1950s,”  stated Todd Sanford, climate scientist at Climate Central.  “Looking at the length of the fire season in Alaska we found, like in the western US, the length of the season is increasing each year…. Wildfire seasons are over a month longer than they were in the 1950s.”

Additional research will further expand understanding of how much wildfires may affect glacier melting.

“In regards to the glaciers in southeast Alaska,” Kehrwald told GlacierHub “we don’t know if it [the reason for the rapid melting of the Juneau Icefield] is temperature only… or if it’s also due to imputes from outside components such as wildfires.”
Kehrwald and O’Neel plan to test their ice core samples in the lab and by later this year have a clearer view of how a greater number of wildfires due to rising temperatures can contribute to glacier melting.

Adventures in Glaciology: Juneau Icefield Research Program

Excavating a back-lit snow pit, August 2005.  Photo by M. J. Beedle
Excavating a back-lit snow pit, August 2005. Photo by M. J. Beedle

By Allen Pope

A lot of people are fascinated by glaciers. Some people even think glaciers are cool enough that they are wiling to spend an entire summer skiing across the Juneau Icefield, digging snow pits, researching glacier dynamics, and seeing some awesome sunsets along the way. Welcome to the Juneau Icefield Research Program, better known as JIRP.

A fiery sunset over Juneau Icefield so stunning it is hard to capture either in pictures or in words. July 23, 2013. Photo by Muriel Will.
A fiery sunset over Juneau Icefield so stunning it is hard to capture either in pictures or in words. July 23, 2013. Photo by Muriel Will.

JIRP’s mission has been to provide an unrivalled educational and expeditionary experience in the stunning Coast Mountains of Alaska and British Columbia. The program gives students (or JIRPers) a wide range of training in glaciology and outdoor skills, providing unique opportunities for team building and personal growth.

Descending "The Cleaver" : approaching the start of the series of fixed ropes - with the Gilkey Trench in the background.  Photo by Adam Toolanen
Descending “The Cleaver” : approaching the start of the series of fixed ropes – with the Gilkey Trench in the background. Photo by Adam Toolanen

Founded over 60 years ago, JIRP has given quite a few glaciologists their start, allowing them to learn about glaciers first-hand in the field. Long-term monitoring and fundamental research are both still integral parts of JIRP: participants are active partners with leading scientists in the pursuit of groundbreaking research, such as using GPS tracking and radar profiles to study the flow speed and thickness of the Juneau Icefield’s glaciers. Meanwhile, JIRP’s ongoing snow pit measurements constitute one of the world’s longest glacier monitoring records. Interdisciplinary Arctic system science is also part of the program, including geology, climatology, and biology, to name just a few topics of study. Finally, the science curriculum is augmented with presentations by professional photographers, filmmakers, and doctors specializing in wilderness medicine.

A group of eager students waits at the door of a camp cookshack for a helicopter to land, delivering fresh food, new faculty, and a few letters from home. Photo by Allen Pope
A group of eager students waits at the door of a camp cookshack for a helicopter to land, delivering fresh food, new faculty, and a few letters from home. Photo by Allen Pope

But you don’t have to take my word for it – you can read what the students have to say. As students traverse the Juneau Icefield, dispatches (and LOTS of beautiful photos) are sent back to civilization and posted to the JIRP blog. JIRPers blog about all sorts of things:

You can check out the full archive here:

JIRPers set out on the skis for a daytrip to explore a new part of the Icefield. Photo by Allen Pope.
JIRPers set out on the skis for a daytrip to explore a new part of the Icefield. Photo by Allen Pope.

Finally, JIRP helps local communities understand what is going on up at the icefield. Students and faculty give presentations in both Atlin, B.C. and Juneau, A.K. about the program, detailing their summer research and giving some context into how the Icefield’s glaciers influence the region.

JIRPer Laurissa explorers a Juneau Icefield crevasse. Photo by Hannah Rosenkrans.
JIRPer Laurissa explorers a Juneau Icefield crevasse. Photo by Hannah Rosenkrans.

JIRP is looking for participants for the 2015 expedition, which will run from June 23 through August 18. Undergraduate, graduate and upper-level high-school students are all welcome to apply; more info is available here. I hope to see you on the Icefield!

And if you want to read more about the science being done up on the Icefield, check out these session abstracts from a recent meeting of the Geological Society of America.

Allen Pope is a member of the JIRP Academic Council and is a postdoc working at the National Snow and Ice Data Center and UW’s Polar Science Center, studying snow and ice, mostly from space. He tweets about the cryosphere, remote sensing, and few other things @PopePolar.