Hiking to Glacier National Park’s Grinnell Glacier

A few days ago I did the hike to Grinnell Glacier, one of the iconic glaciers in Glacier National Park. The glacier lies within the Swiftcurrent drainage area, in the northeastern part of the park. The hike, at least the way I did it, is about 11.6 miles round trip. It is possible to catch a boat ride at the Lake Josephine Boat Dock by the Many Glacier Hotel, which cuts the hike down to about 7.5 miles round trip. But – the first boat goes out at about 8.30 am, and as I didn’t want to wait around for it, I decided that adding on the extra miles for a fairly level stretch around Swiftcurrent Lake and Josephine Lake would be easy to do. It is an easy hike around the lakes and a very good warm-up for the rest of the climb to Grinnell Glacier. But –  be aware that this area is known for grizzly bear activity as I found out when I met up with a grizzly on the trail. Because I’m writing about this encounter,  it obviously ended OK, although I was glad I had bear spray readily available.

The glacier is named after George Bird Grinnell, who first explored this area during the summer of 1885. Because of bad weather, he did not actually get to the glacier during his 1885 travels. However, during the late fall of 1887, he was able to pack most of the way into the glacier by mules, and then hike the remaining distance by foot.  Although he certainly was not the first person to see the glacier, the glacier does bear his name, presumably given it by a Lieutenant John H. Beacom of the United States Army, 3rd Infantry, who accompanied him on the 1887 trip to the glacier.

It’s fun to see ripple marks in the Proterozoic rocks that outcrop along the Grinnell Glacier trail (Grinnell Lake is in the photo’s background).

Back to the hike – after about a mile from the junction of the Swiftcurrent Lake Trail with the trail coming from the North Shore of Lake Josephine boat dock, Grinnell Lake comes into view. A little further along the trail one can see Grinnell Falls dropping several hundred feet down from the headwall behind Grinnell Lake.

Grinnell Falls drops several hundred feet down from the headwall to Grinnell Lake. The Salamander Glacier can be seen in the photo’s upper right-hand corner; Gem Glacier is in the upper left-hand corner of the photo.

And – even at this distance, Salamander and Gem glaciers pop into view in the distant cirque. The hike continues along beautiful alpine meadows and even through one waterfall that cascades down the cliff adjacent to the trail. There is a rest area with pit toilets right before hiking the final switchbacks that traverse the terminal moraine to the Grinnell Glacier Overlook.

The final part of the Grinnell Glacier trail traverses the glacier’s terminal moraine.
Large boulder (Elrod’s Rock) in the Grinnell Glacier’s terminal moraine. Note the marmot atop the boulder for scale. The glacier’s terminus is now about a mile away from this boulder.

The three glaciers that once comprised the Grinnell Glacier occupy parts of a cirque developed along the area called the Garden Wall.

The cirque of the Grinnell, Salamander, and Gem glaciers.

Grinnell Glacier is still the largest of the three ice fields and covers about 152 acres. Unfortunately, this glacier is receding rapidly as the U.S.Geological Survey notes that from 1966 to 2005 it lost about 40% of its acreage. At about 5 acres, the hanging glacier called Gem Glacier, is the smallest named glacier in the park. It sits in the notch on the cliff face above the Grinnell Glacier. This glacier lost about 30 percent of its acreage from 1966 to 2005. The Salamander Glacier covers about 57 acres on a ledge off to the east side of the Grinnell Glacier. It apparently separated from the Grinnell Glacier sometime before 1929 and has undergone a 23% size reduction from 1966 to 2005.

For those interested in viewing photographs of the Grinnell Glacier from various times and viewpoints, the U.S. Geological Survey’s Repeat Photography Project has many archived photographs. This project is a documentation of glacial decline through photography and it is well worth perusing through their photo archives. Two of the earlier photographs are shown below – one from the original 1887 trek and a later view of the glacier from 1940 just to pique one’s interest.

1887 photograph of the Grinnell Glacier taken from footbridge (Lieutenant Beacon, Glacier NP. Public domain).
1887 photograph of the Grinnell Glacier taken from footbridge (Lieutenant Beacom, Glacier NP. Public domain).
Grinnell Glacier from trail 1900; Credit: F.E. Matthes, Glacier NP. Public domain.

Canadian Rockies – Alberta Badlands Geology Guidebook

The Canadian Rockies to Alberta Badlands geology guidebook is published by the Association for Women Geoscientists.

The Association for Women Geoscientists (AWG) published their first geology field trip guidebook in late 2016 and it is now available for sale to the general public. This guideboook is a collection of geology road logs, associated geological information, and local cultural history of areas within the Canadian Rockies and the Alberta Badlands. The following text is a brief summary of the guidebook:

“TECTONICS, CLIMATE CHANGE AND EVOLUTION – SOUTHERN CANADIAN CORDILLERA: Road Log and Accompanying Narratives From: Calgary – Lake Louise – Icefields – Field – Revelstoke – Fernie -Dinosaur Provincial Park – Calgary”, published by the Association for Women Geoscientists, 2016.

This field trip guidebook is written by Katherine J.E. Boggs and Debra L. Hanneman, and edited by Janet Wert Crampton and Stephanie Yager. It is the AWG’s first fully published field trip guidebook and is a field-tested guide from their two-week 2014 field trip through the Canadian Rockies and Alberta’s Badlands area.

The guidebook is a 209-page geology tour through many of the well-known parts of the Alberta Canadian Rockies, including the Front and Main Ranges of the Canadian Rockies and the Columbia Icefields. The Burgess Shale’s Walcott Quarry, the Okanagan Valley vineyards, and the Rocky Mountain Trench are trip highlights for geo-tours in British Columbia. The field trip guidebook ends with a geology tour of the Crowsnest Pass area on the British Columbia/Alberta border, and with field stops in Alberta’s Dinosaur Provincial Park and at the Royal Tyrrell Museum, Drumheller, Alberta.

The field guide is printed on double-sided 8.5″ x 11″ pages with the guide cover on 100 lb paper and the text on 80 lb paper. It has black wire-o binding and a clear acetate front and a black acetate backing for improved field durability. The guidebook’s cost is $55 USD (which includes shipping), and can be purchased at the AWG online store or by phoning the AWG main office at 303-412-6219.

Iceberg Lake Glacier, Glacier National Park – Hiking Through A Changing Landscape

Iceberg Lake is situated in the Many Glacier area of Glacier National Park. The hike is about a 10 mile round trip and gains about 1275 feet in elevation. The trail winds through prime grizzly bear habitat, so be sure to hike with a group, make lots of noise, and carry bear spray. When I hiked the trail back in September, many returning hikers told our group about a grizzly sow and two cubs that were roaming around by Iceberg Lake. The bears actually walked by the lake shore while my group and many others were at the lake, but there were no harmful encounters. However – just this past week, in this same general area, a sow grizzly with 2 sub-adult cubs (I’m guessing that this is the same set of bears that walked by my group at Iceberg Lake) was surprised by a lone hiker and the sow grabbed and shook the hiker. The hiker used his bear spray escaped with puncture wounds to his lower leg and a hand. So – some words of caution about about hiking in bear country!

The Iceberg Lake Trail

A part of the Iceberg Lake Trail - note the u-shape valley sculpted by glacial processes.
A part of the Iceberg Lake Trail – note the u-shape valley sculpted by glacial processes.

The trailhead to Iceberg Lake is behind the cabins near the Swiftcurrent Motor Inn. The first part of the hike, about 1/4 mile, gains about 185 feet. After that initial elevation gain, the trail’s elevation gain moderates. Ptarmigan Falls is about 2.5 miles from the trailhead, and a short way above this is a footbridge that crosses Ptarmigan Creek. The rocky area near the footbridge is a great place for a snack break. Another 1/10 mile beyond the footbridge is the Iceberg Lake Trail junction. The Ptarmigan Trail continues towards the right and goes to Ptarmigan Tunnel and Ptarmigan Lake.Take the other trail branch to continue on to Iceberg Lake. A good trail hike summary for the Iceberg Lake Trail is found at the website “Hiking in Glacier”.

Footbridge over Ptarmigan Creek - good  place for a snack break.
Footbridge over Ptarmigan Creek – good place for a snack break.
Nearing Iceberg Lake as the snow and sleet continue to fall.
Nearing Iceberg Lake as the snow and sleet continue to fall.

The popularity of the trail was clear to me when even on a rainy, sleety, and snowy day,I passed many people on the trail. My group did a leisurely hike, stopping at several places to look at the geology alongside the trail and to do a snack stop by the Ptarmigan Creek footbridge both on the way up and back. It took us about 5 hours for the round trip. That put us back just in time to have a much enjoyed dinner at the Swiftcurrent Motor Inn.

Ah - the trail's end at Iceberg Lake!
Ah – the trail’s end at Iceberg Lake!

 

 

The Iceberg Glacier: Recession from 1940 to the Present

Comparisons of the Iceberg Glacier from 1940 to 2015. The photo on the left is a circa 1940 Hileman photo. GNP Archives; the center photo is a 8/14/2008 photo by Lisa McKeon, USGS, and the photo on the right is a 9/6/2015 photo by Debra Hanneman.
Comparisons of the Iceberg Glacier from 1940 to 2015. The photo on the left is a circa 1940 Hileman photo (GNP Archives) the center photo is a 8/14/2008 photo by Lisa McKeon, USGS, and the photo on the right is a 9/6/2015 photo by Debra Hanneman. Click on the photo to enlarge it in a new window.

The Iceberg Glacier is shown in the above photo set beginning in 1940 (this is the photo on the left, which is a Hileman photo from the Glacier National Park Archives) and ending with the 9/6/2015 photo on the right, which I took during my hike to Iceberg Lake. In the 1940 photo, the glacier terminus is quite thick and extends into the basin. By 2015, there is not much left of the glacier. Even with a comparison between the center 2008 photo by Lisa McKeon and my 2015 photo, one can see that much more bedrock is exposed. The older photos are also posted on the US Geological Survey’s Repeat Photography Map Tour Website. For those interested in glacial recession within Glacier National Park, the Repeat Photography website is a valuable resource. The Repeat Photography project is summarized on the USGS website –

This project began in 1997 with a search of photo archives. We used many of the high quality historic photographs to select and frame repeated photographs of seventeen different glaciers. Thirteen of those glaciers have shown marked recession and some of the more intensely studied glaciers have proved to be just 1/3 of their estimated maximum size that occurred at the end of the Little Ice Age (circa 1850). In fact, only 26 named glaciers presently exist of the 150 glaciers present in 1850.

Trail Geology

Sheet sands interbedded with muds in Proterozoic Grinnell Formation.
Jeff Kuhn points out sheet sands interbedded with muds in Proterozoic Grinnell Formation.

Much of the Iceberg Lake Trail winds through the Grinnell Formation, which is a Proterozoic geologic unit within the Belt Supergroup. As Callan Bentley has succintly said of the Belt Supergroup rocks in Glacier National Park:

The rocks exposed firstly from the top down are old sedimentary rocks of the Belt Supergroup. It is called “Belt” after Belt, Montana, and “supergroup” because it is immense. These rocks were deposited in a Mesoproteozoic (1.6-1.2 Ga) sea basin, and show little to no metamorphism despite their age.

Rip-up clasts in Proterozoic Grinnell Formation.
Rip-up clasts in Proterozoic Grinnell Formation.

I was lucky to be hiking with Jeff Kuhn from Helena, Montana, who has done much work with Belt Supergroup rocks in the Glacier Park to Whitefish Range areas. Jeff stopped us at several locations along the trail to look more closely at features within the Grinnell Formation. In general, the Grinnell Formation consists of sandstone and argillite and is approximately 1740-2590 feet thick. It has a deep brick-red color owing to its contained hematite and because it was deposited in a shallow oxygen-rich environment. Sedimentary features that are consistent with the shallow water depositional interpretation include mudstone rip-up clasts, mudcracks, and ripple marks.

Mudcracks preserved in the Proterozoic Grinnell Formation.
Mudcracks preserved in the Proterozoic Grinnell Formation.

All told, it was a hike well worth doing, even if you are not a geology enthusiast!

Ripples preserved in the Proterozoic Grinnell Formation.
Ripples preserved in the Proterozoic Grinnell Formation.

 

A Different Look At The Burgess Shale – The Stanley Glacier Burgess Shale Hike, Kootenay National Park, British Columbia, Canada

The Middle Cambrian Burgess Shale and its contained fossils are legendary to earth scientists. These fossils are by far the best record of Cambrian animal fossils. The importance of the Burgess Shale fossils is also linked to their excellent preservation. The fossils include many soft bodied animals in addition to those with hard parts – an extremely rare occurrence for fossil assemblages.

I finally hiked to the Walcott Quarry on Fossil Ridge near Field, B.C., last year, just to better understand the context of the Burgess Shale. It was well worth the effort (it is a long, and as other hikers phrased it – a gut-busting hike). Before my Walcott Quarry hike, I’d read that Kootenay National Park just started hosting hikes to Burgess Shale type faunas (BST) in the Stanley Glacier area. It only took a good dinner and a beer after the Walcott Quarry hike to decide that I’d do the Stanley Glacier Burgess Shale hike.

Stanley Glacier Valley, Kootenay National Park - the view is looking west from the upper talus slopes.
Stanley Glacier Valley, Kootenay National Park – the view is looking west from the upper talus slopes.

Stanley Glacier BST fossils (approximately 505 million years in age) are about 40 km southeast of the Field, B.C. (Yoho National Park) locales. Recent work in both the Marble Canyon and the Stanley Glacier areas of Kootenay National Park yielded noteworthy additions to understanding the BST fossils and their depositional environments. BST fossils found in the Marble Canyon area include 25 new species of organisms; 8 new species are now recorded for the Stanley Glacier BST fossils. Of more interest to me (being a sedimentologist), is that the depositional environment in the Kootenay National Park area differs from that of the Field, B.C. area. Although the Burgess Shale fossils are found within the Stephen Formation in both areas, there is a marked difference in this rock unit from one area to the other area. Around Field, B.C., the Stephen Formation is the “thick or basinal” (about 276 to 370 meters thick) Stephen and it resulted from deposition at the base of the older Cathedral Formation Escarpment (a submarine cliff) via turbidity flows. In the Stanley Glacier area, the Stephen Formation is relatively “thin” (about 33 meters thick) and is probably the result of deposition at the distal edge of a marine platform (Caron and others, 2010; Gaines, 2011). The stratigraphic placement of the Burgess Shale rock units also differs from the Field, B.C. area to the Stanley Glacier area. Based upon the presence certain trilobites and stratigraphic evidence (Caron and others, 2010), the “thin” Stephen Formation at Stanley Glacier is stratigraphically above the Field, B.C. Burgess Shale localities.

The Cambrian rock units on the south wall of the Stanley Glacier area. The Stephen Formation is the unit that contains the Burgess Shale type fossils. The lockbox location is the hike’s end.

With that small bit of Burgess Shale background, I’ll get back to the actual hike up the Stanley Glacier valley to the Stephen Formation talus slopes and outcrop. The hike is hosted by Kootenay National Park and is about 10 km for the round trip. The elevation gain is about 450 meters. The first part of the hike is through glacial material and a fire-swept lodgepole pine forest. Forest fires burned through this area most recently in 1968 and in 2003. Luckily for paleontologists, the fire bared many slopes and definitely helped in locating BST fossil beds. A little more than halfway through the hike, one breaks out of the trees onto the talus slopes of Stanley Glacier’s valley. The hike continues over the talus slope to a very large boulder. Several BST fossil specimens are locked in a box kept behind this boulder. Our guide gives an informative talk about the lockbox fossils and we have much time to pick around the talus slope for more fossils.

Burgess Shale type fossil specimens are kept in a lock box behind the large rock. These specimens are the focus of an informative talk by the Kootenay National Park hike guide.
Burgess Shale type fossil specimens are kept in a lockbox behind the large rock located on the talus slope. These specimens are the focus of an informative talk by the Kootenay National Park hike guide.

In 1989, an expedition party from the Royal Ontario Museum (ROM) located fossils from Stephen Formation talus in this area (Rigby and Collins, 2004: Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia; Royal Ontario Museum Contributions in Science 1: 1–155.). Caron and others (2010) also document that some of their fossil assemblage material came from the talus slope, so it’s worth some time to look around (Caron and others, 2010 GSA Data Repository).

Talus slopes beneath the Cambrian Stephen Formation are prime areas for Burgess Shale type fossils.
Talus slopes beneath the Cambrian Stephen Formation are prime areas for Burgess Shale type fossils.

Keep in mind that this is within a Canadian National Park, so do not keep any of the fossil material. The quarry that has been worked recently in this area (the quarry was initially worked in 2008 by ROM earth scientists) is yet beyond the hike’s end point, near the southwest edge of the cirque.

Stanley Glacier BST shelly fauna includes characteristic Cambrian taxa such as hyolithids, brachiopods, and trilobites. Soft-bodied BST creatures such as the necktobenthic or nektonic arthropods and proto-arthropods Stanleycaris hirpex n. gen., n. sp., Tuzoia retifera, and Sidneyia inexpectans also are part of the BST fauna. Trace fossils are plentiful on some bedding surfaces. These include trails, shallow burrows, and arthropod trackways.

Tuzoia - a fossil arthropod specimen from the lockbox collection.
Tuzoia – a fossil arthropod specimen from the lockbox collection.
Sidneyia - a fossil arthropod from the lockbox collection.
Sidneyia – a fossil arthropod from the lockbox collection (this specimen is actually from Marble Canyon).
Sponge spicules - from the fossil lockbox collection.
Sponge spicules – from the fossil lockbox collection.
Haplophrentis - an enigmatic tubular fossil known as a hyolith. This fossil is from the lockbox collection.
Haplophrentis – an enigmatic tubular fossil known as a hyolith. This fossil is from the lockbox collection.
Anomolarcaris claw - from the lockbox collection.
Anomalorcaris claw – from the lockbox collection.
Feeding traces - from the talus slope near the lockbox.
Feeding traces – from the talus slope near the lockbox.

Canadian Rockies AWG Field Trip – A Summary

The AWG 2014 Canadian Rockies Field Trip took place from August 28 to September 7, 2014, with a Calgary-area geology pre-trip for early arrivals on August 27.  The main part of the field trip commenced with a mid-morning departure on the 28th from Calgary, and we all headed west along Canada Highway 1 to Lake Louise. After spending two days in the Lake Louise area, we drove north to the Columbia Icefields. A few of us continued further north the next day, on an side trip to Jasper. From the Icefields we toured south to Field, British Columbia, over to Revelstoke, and ended our British Columbia time in Fernie. We then drove east, back into Alberta, and spent time at Dinosaur Provincial Park near Brooks and at the Royal Tyrrell Museum of Palaeontology in Drumheller. The trip ended with our group once more back in Calgary, Alberta.

There were 22 people as full-time field-trippers and two more people on the trip during the Icefields to Field, B.C. part of the trip. Two of the full-time trip participants were students and one of the additional, part-time trip participants, was a student. All of the students on the field trip are from Mount Royal University in Calgary and are students of our field trip leader, Katherine Boggs. Paul Hoffman and Mindy Brugman also helped out for a day or so during the trip. Marcia Knadle and Debra Hanneman did the trip budget and logistics. We had a great field trip guidebook, thanks largely to Katherine Boggs’ efforts. The field trip guidebook, “Tectonics, Climate Change, and Evolution: Southern Canadian Cordillera” will be on sale at the AWG online store soon.

Some of us took to the water and canoed around Moraine Lake near Lake Louise, Alberta. Moraine Lake is located within the valley known as the “Valley of the Ten Peaks” which was once featured on the Canadian twenty dollar bill.
Some of us took to the water and canoed around Moraine Lake near Lake Louise, Alberta. Moraine Lake is located within the valley known as the “Valley of the Ten Peaks” which was once featured on the Canadian twenty dollar bill.
Katherine Boggs talks to the field trip crew about area geology at a stop along the Icefields Parkway in Alberta.
Katherine Boggs talks to the field trip crew about area geology at a stop along the Icefields Parkway in Alberta.
Our intrepid field crew hikes the Athabasca Glacier, one of the six major glaciers of the Columbia Icefield.
Our intrepid field crew hikes the Athabasca Glacier, one of the six major glaciers of the Columbia Icefield.
Paul Hoffman explains features of the Neoproterozoic Old Fort Point Formation near Jasper, Alberta.
Paul Hoffman explains features of the Neoproterozoic Old Fort Point Formation near Jasper, Alberta.
Some of the field trip group took the arduous hike up to the famous Walcott Quarry that is developed within the Cambrian Burgess Shale near Field, British Columbia.
Some of the field trip group took the arduous hike up to the famous Walcott Quarry that is developed within the Cambrian Burgess Shale near Field, British Columbia.
A member of our field trip group shows us one of the Burgess Shale’s trilobites from the Walcott Quarry.
A member of our field trip group shows us one of the Burgess Shale’s trilobites while at the Walcott Quarry.
One of the trip’s frequent rainy days – but we still had fun by the Kicking Horse River at its confluence with the Columbia River, near Golden, British Columbia.
One of the trip’s frequent rainy days – but we still had fun by the Kicking Horse River at its confluence with the Columbia River, near Golden, British Columbia.
Our field trip group poses by Columbia Lake, which forms the headwaters for both the Columbia and Kootenay rivers, and lies within the enigmatic Rocky Mountain Trench near Canal Flats, British Columbia.
Our field trip group poses by Columbia Lake, which forms the headwaters for both the Columbia and Kootenay rivers, and lies within the enigmatic Rocky Mountain Trench near Canal Flats, British Columbia.
The Frank Slide was a must-stop as we drove along the Crowsnest Highway near Blairmore, Alberta. The slide happened on April 29, 1903, when about 82 million tons of limestone fell off of Turtle Mountain.
The Frank Slide was a must-stop as we drove along the Crowsnest Highway near Blairmore, Alberta. The slide happened on April 29, 1903, when about 82 million tons of limestone fell off of Turtle Mountain.
Part of our field trip group discusses Centrosaur Bone Bed 43 during our guided hike at Dinosaur Provincial Park, Alberta.
Part of our field trip group discusses Centrosaur Bone Bed 43 during our guided hike at Dinosaur Provincial Park, Alberta.

Greenland’s Fastest Glacier Now Flowing At Record Speeds

Jakobshavn Isbræ, Greenland’s fastest flowing glacier, has been moving even faster over the past several years. The Jakobshavn Glacier, or Jakobshavn Isbræ, is located on the west coast of Greenland and drains a major part of the Greenland ice sheet into a deep ocean fjord. Accordingly, the Jakobshavn Glacier could add significantly to sea level rise.

Recorded speeds of glacial flow during the summer of 2012 topped out at more than 17 kilometers per year, or over 46 meters per day. In fact, the transient summer speeds observed for 2012 probably represent the fastest observed speeds for any outlet glacier or ice stream in Greenland or Antarctica. In a paper published recently in The Cryosphere, Joughin and others, note that:

We have extended the record of flow speed on Jakobshavn Isbræ through the summer of 2013. These new data reveal large seasonal speedups, 30 to 50% greater than previous summers. At a point a few kilometres inland from the terminus, the mean annual speed for 2012 is nearly three times as great as that in the mid-1990s, while the peak summer speeds are more than a factor of four greater. These speeds were achieved as the glacier terminus appears to have retreated to the bottom of an over-deepened basin with a depth of 1300m below sea level. The terminus is likely to reach the deepest section of the trough within a few decades, after which it could rapidly retreat to the shallower regions 50 km farther upstream, potentially by the end of this century.

The warming trend in the Arctic correlates with Greenland’s glaciers thinning and retreating progressively inland. The rapid retreat of the Jakobshavn Isbræ, however, is due not only to the warming trend, but to a number of feedbacks. The primary control on the glacial flow now is the physical location of the glacier’s calving front. The calving front is currently located in a deep area of its outlet fiord, an area where the underlying rock bed is about 1300 meters below sea level. As the glacier loses ice in this area – basically the ice in front that is holding back the flow – the flow speeds up.

The contribution to sea level rise from the Jakobshavn Isbræ may be significant. One of the study’s authors, Ian Joughlin, is quoted in Science Daily, 2/3/2014, as saying:

We know that from 2000 to 2010 this glacier alone increased sea level by about 1 mm. With the additional speed it likely will contribute a bit more than this over the next decade.

So what should we expect for the Jakobshavn Isbræ’s future? Joughlin and others summarized this by:

Thus, the potential for large losses from Greenland is likely to be determined by the depth and inland extent of the troughs through which its outlet glaciers drain. These features are only beginning to be well resolved by international efforts such as NASA’s Operation IceBridge. The relatively sparse data collected thus far indicate that, with its great depths and inland extent, Jakobshavn’s Isbræ is somewhat unique (Bamber et al., 2013), suggesting that it may be difficult for the majority of Greenland’s outlet glaciers to produce or to sustain such large increases in ice discharge.

Of interest may be an earlier Geopostings on “Chasing Ice” that showed a 2012 huge calving event from the Jakobshavn Isbræ.