Cummins Glacier Fragmentation, British Columbia

On November 17, 2015May 2, 2024 By mspeltoIn Canada glacier retreat, glacier climate change, Glacier Observations

Comparison of the Cummins Glacier from 1986 to 2015. Purple arrows indicate upglacier thinning and disconnection. Red arrow indicates 1986 terminus position. Note the lack of snowcover in 2015.

The Cummins Glacier is part of the Clemenceau Icefield Group in the Rocky Mountains of British Columbia. The Cummins Glacier via the Cummins River feeds the 430 square kilometer Kinbasket Lake, on the Columbia River. The lake is impounded by the 5,946 MW Mica Dam operated by BCHydro. Jiskoot et al (2009) examined the behavior of Clemenceau Icefield and the neighboring Chaba Icefield. They found that from the mid 1980’s to 2001 the Clemenceau Icefield glaciers had lost 42 square kilometers, or 14% of their area. Tennant and Menounos (2012) examined changes of the Rocky Mountain glaciers and found between 1919 and 2006 that glacier cover decreased by 590 square kilometers, 17 of 523 glaciers disappeared and 124 glaciers fragmented into multiple ice masses. Here we examine the Landsat images from 1986-2015 to illustrate that Cummins is one of those fragmenting glaciers.

Cummins Glacier on the western side of the Clemenceau Icefield shares a connection with Tusk Glacier.

In 1986 Cummins Glacier had a joint terminus with the main southeast flowing branch and the west flowing branch terminating at the red arrow. The glacier also had a substantial connection, purple arrow, with Tusk Glacier that flows east terminating northeast of Tusk Peak. There are other connections with other high elevation accumulation areas, purple arrows. In 2013 and 2014 Cummins Glacier had less than 20% retained snowcover by the end of the melt season. Typically 50-65% of a glacier must be snowcovered at the end of the summer season to be in equilibrium. In 2015 conditions were even worse with no retained snowcover, in fact there is only minor patches of retained firn from previous years. The lack of a persistent accumulation zone indicates a glacier that cannot survive the climate conditions (Pelto, 2010). By 2015 a proglacial lake had formed at the terminus that is 500 m long, representing the retreat during the thirty year period. The west flowing portion of the Cummins has detached from the larger branch. The connection to Tusk Glacier is nearly severed, and in terms of flow is effectively ended. Retreat of the margin higher on the glacier is also evident at each purple arrow. Tusk Glacier is no longer connected to Duplicate Glacier, and has retreated to the north side of Tusk Peak. The dominant change in Cummins Glacier has been thinning, it should now be poised for a more rapid retreat.

The result for Kinbasket Lake of the loss of the collective large area is a reduction in summer glacier melt and summer glacier runoff. The annual runoff which will be dominated by annual precipitation would not change just because of the glacier loss as noted in cases like the Skykomish Basin (Pelto, 2011) and on Bridge River (Stahl et al 2008).

2013 Landsat image indicating 20% retained snowcover with a month left in the melt season.

Landsat image 2014 about 25% retained snowcover with three week left in the melt season.

Google Earth Image of Cummins Glacier location to Kinbasket Lake.

Why Glaciers are not like Swiss Cheese

On November 12, 2015 By mspeltoIn glacier climate change, Glacier Observations

There have been a number of quotes indicating that glaciers/ice sheets are like swiss cheese. Swiss cheese has holes and has little structural strength, and is often used as a metaphor to imply weakness. In the ablation zone of many glaciers there are holes, moulins, that are typically 0.5-10 m wide. A moulin is a narrow, tubular conduit in a glacier that provides a pathway for water to travel from the glacier’s surface towards the glacier base. A moulin is carved by an active flow of water, which has considerable energy as it falls. The volume of water cannot be refrozen in most cases, as there is just too much of it. As a result the water that enters a moulin eventually exits the glacier usually at the glacier base. I have observed hundreds of moulins and routinely measure their depth each summer and the ability of water communicated into them to be transmitted through the glacier using dye. Our measurements on the alpine glaciers of Alaska and Washington document typical depths of the first near vertical drop of 5-30 m. Many if not most moulins form by taking advantage of a crevasse or former crevasse via hydrofracturing. Crevasse depths are not often much greater than 30 m which is likely related to the the initial vertical drop of most moulins. At that point the moulin will access an internal drainage system. We find that the velocity of surface streams on a glacier within a kilometer of the terminus are an order of magnitude faster than the the streams of the englacial-subglacial stream system. Below is video footage from within moulins using a GoPro and of surface streams feeding into moulins in the North Cascades filmed this summer.

Moulins are not points of weakness that lead to collapse of adjacent ice. They do not develop sinkholes. They are more like a pinprick in diameter compared to the thickness of a glacier. For the Greenland Ice Sheet Das et al (2008) identified moulins delivering water to the base where the ice was 1000 m thick, the moulins less than 10 m in diameter. Joughin et al (2013) note that moulins are tied into extensive stream networks and are sparsely distributed in the lake-dominated region of the Greenland Ice Sheet. They are both small in size compared to the glacier and typically far apart, not like swiss cheese. Smith et al (2015) note this same fact mapping 532 streams all ending in moulins in an area of 6812 square kilometers. Clason et al (2015) examined the hydrology of the Leverett Glacier of western Greenland and found in their modelling a density of moulins below 1000 m is 1-3 per square kilometer and above 1000 m is less than 0.2 per square kilometer. Again the moulins are the key to delivering most meltwater to the glacier base, but are small and widely spaced compared to glacier area. McGrath et al (2011) examined a watershed on Sermeq Avannarleq, West Greeenland that had a single large mouline that was key to drainage. They found numerous englacial fractures 40-70 m below the surface in the moulin system. They further note the widespread existence of refrozen englacial voids and fractures from an old moulin. This suggests the lack of overall structural weakness imparted by moulins.

Moulins are quite important to the hydrologic system of a glacier in the ablation zone as they are such an efficient means of directing surface meltwater to the glacier base. This meltwater can accelerate the flow of a glacier, by increasing basal water pressure. If the hydrologic system is insufficient to easily transfer the water towards the glacier terminus, this leads to a high water pressure, and the water acts like a lubricating fluid. However, if the hydrologic system is sufficiently developed in part by the moulins, then the meltwater simply flows through sufficient tunnels at the base of the ice, with limited basal water pressure and do not lead to acceleration. This potential to both raise and limit ice velocity is why moulins are such an important area of research.

Balfour Glacier, New Zealand Retreat 1990-2015

On November 5, 2015May 2, 2024 By mspeltoIn glacier climate change, Glacier Observations, New Zealand glacier

Balfour Glacier drains west from Mount Tasman in the Southern Alps of New Zealand. The ablation is a low slope, 8 km long debris covered tongue extending from the terminus near 800 m to 1600 m. The glacier is fed by avalanching off of Mount Tasman to the west, the southern flank of the Fox Range to the north and the northern flank of the Balfour Range to the south. Gjermundsen et al (2011) examined the change in glacier area in the central Southern Alps and found a 17% reduction in area mainly from reductions of large valley glaciers such as Balfour Glacier. The volume loss of New Zealand glaciers is reported as 36% from 1978 to 2015, from 54 cubic km to 34 cubic km.

Topographic map of Balfour Glacier area of New Zealand from http://www.topomap.co.nz/ . Blue arrows indicate flow, red arrows at 1990 terminus and yellow arrow at 2015 terminus

In 1990 the glacier ended at 700 m with a snowline at 1600 m. The lower 18 km of the Balfour Glacier is debris covered. Only the upper 8 km has snowcover. In 2015 the terminus has retrated 1250 m, the snowline is at 1800 m, with the lower 20 km debris covered. The terminus reach has continued to appear stagnant from 1990 to 2015. Balfour Glacier has not developed a significant proglacial lake at its terminus, which has limited the retreat compared to Tasman Glacier or Mueller Glacier. Google Earth indicates the retreat of stagnant debris. The main glacier meltwater outlfow issues from the glacier at the yellow arrow in 2012, 600 m above the terminus.

Landsat Analysis of 1990 above and 2015 Below of Balfour Glacier. Red arrow is at 1990 terminus and yellow arrow at 2015 terminus. The purple arrows indicate area of thinning upglacier.

2006 Google Earth image of Balfour Glacier above and 2012 image below. The red arrow is at the terminus location in 2006, the yellow arrow is at the 2012 location where the glacier stream issues from beneath the glacier. The purple arrows

Glacier Retreat expands Gelhaipuco Lake

On November 2, 2015May 2, 2024 By mspeltoIn china glacier retreat, glacier climate change, Glacier Observations

Fig. H. Gelhaipuco Glacier (G) and Qangzonkco Glacier (Q) change from 1991 to 2015, red arrow indicates 1991 terminus, yellow arrow 2015 terminus and purple arrow indicates areas of thinning.

Gelhaipuco is a glacier moraine dammed lake at the headwaters of the Natangqu River in the Pumqu Basin, Tibet, China. In 1964 the lake had an outburst flood that resulted in severe damage and economic losses in the Chinese Tibet and downstream in the Arun valley in Nepal. The flood occurred after a heavy rainstorm with the rising lake overtopping and eroding the moraine dam significantly. Today the water level is lower than the 1964 pre-flood water level. The glacier that ends in it is unnamed, but is referred to here as Gelhaipuco Glacier. Che et al (2014) reports that glaciers in the basin lost 19% of total area since the 1970’s and that the retreat rate increased in the 2001-2013 period. The number of glacier lakes has increased from 199 to 254 since the 1970’s. Of these 19 are deemed dangerous including Gelhaipuco (Che et al, 2014) . The lake has an estimated volume of ~25 million cubic meters and is a risk for a glacier outburst flood.The Arun River has a proposed 900 MW hydropower plant under development in Nepal. In 1991 the glacier terminates at the red arrow in the lake, which was 750 m long. By 2015 glacier retreat had expanded the lake to 1500 m. The glacier retreat of 800 m is occurring in a lake that is maintaining consistent width. The retreat is fueled by high snowlines such as in 2015, the snowline was at 5800 m, with no retained snowpack across the glacier divide to a separate terminus that flows east. The terminus reach of the glacier has crevassing within 250 m calving front, indicating the role of iceberg calving. The glacier lacks crevasses above this point for a kilometer, indicating the limited velocity to support the current level of melting and calving. retreat will continue and the lake volume will continue to increase in the next decade. The upvalley lake limit will likely be reached within the next kilometer of retreat.

Gelhaipuco lake and its unconsolidated moraine dammed lake. Note the elevation listed near the former shoreline and the current outlet stream.

Snowline on Gelhaipuco Glacier in 2015 at purple dots-5800 m. Note there is no retained accumulation across the glacier divide from the east to west terminus.

Blágnípujökull, Iceland Retreat 1986-2015

On October 26, 2015May 2, 2024 By mspeltoIn glacier climate change, Glacier Observations, iceland glacier retreat

Blágnípujökull comparison in Landsat imagery from 1986 and 2014.

Blágnípujökull is an outlet glacier on the western side of Hofsjökull. The Iceland Glaciological Society spearheads an annual terminus monitoring program led by Oddur Sigurðsson. This data set enabled an examination of glacier response to climate change in Iceland from 1930-1995 by Tómas Jóhannesson, Icelandic Meteorological Office and Sigurðsson (1998). This illustrated that Hofsjökull glaciers retreated little from 1950 to 1990, but all retreating significantly after 2000. Here we examine Landsat imagery of Blágnípujökull terminus change from 1986 to 2015.

Outlet map of the glacier from the Iceland Glaciological Society.

Iceland Glaciological Society data on terminus change, notice change from advance to retreat in the 1990’s

In 1986 the glacier terminated at the red arrow. North of the main terminus is a separate glacier terminus, purple arrow. By 1998 there is limited retreat less than 200 m. By 2014 the terminus area around the purple area has been largely lost. The glacier has retreated from the red dots to the yellow dots, a distance of 600 meters. The thinning is also evident in the region between the two main termini of Blágnípujökull, the margin is not as close to the edge of the lava flow capping the hill that the glacier terminus parts around. The snowline is also quite high on the ice cap in 2014. In 2015 the image is after a summer snowstorm and the is not clear enough to accurately assess further terminus change. The changes in this glacier parallel those of other Iceland Glaciers: Porisjokull and Langjokull.

1986 Landsat Image

1998 Landsat Image

2014 Landsat Image

Google Earth image

2015 Landsat Image

Kronebreen and Kongsvegen, Svalbard Initiation of Glacier Separation 2015

On October 19, 2015May 2, 2024 By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations, svalbard glacier retreat

Kronebreen terminus in 2013 (left) and 2015 (right), note the configuration change and separation initiation of Kronebreen and Kongsvegen at yellow arrow.
Kronebreen is a large, (450 km2) tidewater glacier on the northwest coast of Svalbard terminating in a shared terminus with Kongsvegen at the head of Kongsfjorden. Changes in 2015 indicate the shared terminus will not continue. Luckman et al (2015) observed Kronebreen has a winter speed of 1.5–2 m/day, with summer peaks of 3–4 m/day associated with positive air temperatures and periods of high rainfall. The terminus of the glacier was relatively stable from 1990 to 2001 with even a slight advance at the end of that period (Trusel et al, 2010). The fjord lacks a significant sill at its mouth resulting in significant connectivity with water masses of the West Spitsbergen Shelf, including Atlantic Water Trusel et al, 2010). This aspect during summer can aid in frontal ablation and terminus retreat as noted in Figure 2a from Luckman et al (2015). Shellenberger et al (2014) observed that the period of Kronebreen stability ended in 2007 and that the glacier retreated 850 m and lost 2.1 square kilometers from 2007-2013. Long term they observed that the ablation loss of the terminus reach increased from 0.14 Gt per year from 1960-1990, to 0.20 Gt per year from 1990-2007 and was 0.21 Gt per year in 2013. The University Centre in Svalbard has established a set of cameras for time lapse work at the terminus, which is fortuitous given the changes that have occurred recently. In 2015 returning in the spring University Centre in Svalbard researchers noted the thinning and stretching of the terminus reach: Doug Benn, Penelope How, Heidi Sevestre and Nick Hulton. Penelope How examines the deployment of the cameras in 2015. Here we examine Landsat images to provide a snapshot of the changes that the above researchers have examined in detail.
Map of Glacier front from TopoSvalbard.
In 1987 the joined front terminated near the western tip of Colletthogda, red arrow. The purple arrows indicate locations for comparison to 2015 of glacier thinning. By 1998 there has been a small retreat, that will be erased by a small advance the following years. I 2011 the front remains a single linear front, the greater level of crevassing of Kronebreen is evident as well as the shallower water on the southern margin of the fjord the Kongsvegen terminus. In 2013 a larger retreat has begun, the calving front is concave with more retreat on the southern, Kongsvegen side of the terminus. In 2015 substantial changes have occurred. The front of Kronebreen has retreated 1200 m on the northern margin since 1998 and 1500 m on the southern lateral moraine, this is 300-500 m since 2013. The most striking element is the right angle turn in the calving front at the lateral moraine with Kongsvegen. This is not a stable configuration. This represents the initiation of the separation of Kronebreen and Kongsvegen. The weakness along which the process is taking place is the lateral moraine. Kronebreen terminates in deeper water and can retreat more rapidly via calving. This retreat has been driven by enhanced ablation both at the surface and by the ocean. The higher velocity of Kronebreen is clear in the video of the glacier from the University Center of Svalbard. The process of separatiion is a trend in Svalbard note Samarinbreen.and Vasilievbreen.
1987 Landsat image

1998 Landsat image

2011 Image from TopoSvalbard, note the differenence in level of calving between Kronebreen and Kongsvegen.

2013 Landsat image

2015 Landsat image

Engabreen Glacier, Norway Retreat

On October 15, 2015May 2, 2024 By mspeltoIn glacier climate change, Glacier Observations, Norway glacier retreat

Engabreen is an outlet glacier of the Svartisen ice cap in northern Norway. It has an area of 40 km2. Most of the area lies between 1200 and 1450 m the high plateau of the ice cap. This glacier has been the focus of attention from the Norwegian Water Resources and Energy Directorate (NVE) for over 50 years.

Google Earth image of Engabreen Glacier, 2014.

NVE maintains the most extensive and detailed glacier monitoring network in The NVE annual mass balance measurements on Engabreen indicate that winter snow typically accumulate 3 m of water equivalent on the ice cap. This amounts to 5-7 m of snowpack as the melt season begins in May. The glacier terminus descends from the ice cap down nearly to Svartisvatnet, a lake at 7 m. At the terminus annual melting is 12 m. The rivers from the northern and eastern side of Svartisen were regulated in the 1990’s for hydro power production by construction of a tunnel system partly underneath the glacier. Today about 60% of the potential runoff of the Engabreen is captured and sent through a bedrock tunnel to the hydropower facility. During completion of this tunnel access to the glacier base was opened. Today there is the world’s only ongoing subglacial laboratory here The melt water from Engabreen is collected into this tunnel system at 620 m a.s.l. underneath 200 m of glacier ice in the ice fall. The sub-glacial blog has further details of this mainly winter research location

Late in the 18th century Svartisvatnet,the lake below the terminus, started to appear as the glacier retreated upvalley. In 1903 regular length change observations were initiated, a small advance ensued until 1910. By 1931 the glacier retreated 100 meters, and the glacier tongue was thinning. During the next decade calving led to rapid retreat revealing the rest of Engabrevatnet. This period of retreat ended in 1965, Engabreen advanced with three different pulses ending in 1971, 1984 and 1999, the last pulse reaching to within a few meters of the lake shore.Below are pictures from the NVE taken in 2000 and 2008 of Engabreen, note the large contraction of the terminus area. This is further illustrated in Landsat images below.

NVE images of Engabreen Glacier

From 1990 the glacier ended at the red arrow before advancing by 1999 to the purple arrow. Retreat followed to the yellow arrow in 2015, this is a 350 m retreat. From 1999-2013 NVE amual terminus assessment indicates a retreat of 317 m.. At the green arrow the width of the glacier declined from 475 m in 1999 to 325 m in 2015. At the orange arrows thinning is evident higher on the glacier as bedrock areas have expanded. The snowline in 2014 is above these areas and is at all but one in 2015. This thinning suggest retreat will continue. The 2015 position is its point of furthest retreat since the Little Ice Age. The recent retreat indicates a recent trend of negative mass balance on the glacier. There is excellent flow off the ice cap that has persistent and consistent snowcover indicating this glacier will survive current climate. This is also leading to the retreat of Storglombreen and Flatisen from the same ice cap

1990 Landsat image

1999 Landsat image

2014 Landsat Image

2015 Landsat image

Fingers Glacier, Alaska loses a finger to melting

On October 6, 2015May 2, 2024 By mspeltoIn alaska glacier retreat, climate change glacier retreat, glacier climate change, Glacier Observations

Landsat comparison of terminus area of Fingers Glacier 1986 and 2015

Fingers Glacier flows from the southern end of the Fairweather Range to the coastal plain, where is expands into a segmented piedmont lobe. The southernmost finger is heavily debris covered. In the Mount Fairweather B-4 quadrangle USGS map based on 1951 aerial photographs the glacier has four prominent fingers each eroding its own basin. Here we examine Landsat imagery to illustrate the changes in this glacier from 1951 to 2015. From 1950-1980 glacier’s just to the north In Lituya Bay were advancing. The La Perouse Glacier its immediate neighbor to the north was stable. Palma Glacier directly to the southeast has retreated throughout the 1950-2015 period. Larsen et al (2015) identify that from 1994-2013 this region of Alaska is a significant source of glacier volume loss and hence contributor to sea level rise. The loss of 75 gigatons per year from glaciers in southern Alaska was determined in this study to be largely from surface melt not from calving losses. The mass balance of both Taku and Lemon Creek Glacier of the Juneau Icefield have had a notable decline in mean mass balance from 1986-2015 versus the 1951-28985 period (Pelto et al, 2013). The nearby Brady Glacier also experience a higher snowline (Pelto et al, 2013b) which led to volume losses quantified by Larsen et al (2015).

USGS map based on 1951 images

By 1986 the glacier still had four fingers with retreat from the 1951 position yellow arrow to the 1986 position red arrows. Retreat was 900 m for the first finger, 400 m for the second finger, 300 meters for the third and 400 meters for the fourth southernmost finger. A new lake had developed at the second finger, well lake expansion occurred at the first and third finger. By 1999 a lake is beginning to form at the fourth finger. In 2015 the first finger has retreated 600 meters in 30 years. The second finger has disappeared after a 700 m retreat from 1986-2015.. The third finger has lost half of its length to the expanding lake, a retreat of 600 m in 30 years. The fourth finger which is the most debris covered, leading to slower thinning, has retreated 600 meters since 1986, with a lake at the terminus that is continuing to expand.

1986 Landsat Image

1999 Landsat Image

2015 Landsat Image

Google Earth Image indicating flowlines.

Palma Glacier, Alaska Retreat Opens Lake Passage

On October 1, 2015May 2, 2024 By mspeltoIn alaska glacier retreat, glacier climate change, Glacier Observations

An August 1986 and September 2015 Landsat Image of Palma Glacier, 1986 terminus yellow arrow.
Palma Glacier is an unnamed glacier just west of Brady Glacier and Glacier Bay that is the principal glacier draining into Palma Bay. Here we examined the changes in this glacier from 1986 to 2015 with Landsat Imagery. The glacier has terminated in a lake at the head of a river draining into Palma Bay at least since the 1950 USGS map was prepared.The neighboring Brady Glacier advanced for much of the 20th century, its tributary lobes began to retreat after 1970. The main Brady Glacier terminus did not begin to retreat until 2009 and is poised to begin a rapid retreat as lake development at the terminus continues due to ongoing thinning (Pelto et al, 2013)..

Google Earth image of the Palma Bay and Palma Glacier region

In 1986 Palma glacier flowed south out of the mountains before turning sharply west for 2 km before terminating in a lake at the yellow arrow. The lake had considerable debris covered ice bergs that had recently calved. By 1999 the glacier had retreated to the westward turn, red arrow, but did extend to the south side of the lake. By 2014 the glacier had retreated from the westward turn, red arrow, and the strip of land between the two lakes at the purple arrow has been exposed and vegetated. it is now possible to paddle up one lake and portage to the next. The snowline purple dots is at 1000 m. In 2015 this September image at top is after an early season snowfall, the last image below is an August image indicating the snowline is again at 1000 m with several weeks left in the melt season. The glacier has retreated 2100 meters from 1986 to 2015 and still terminates in the lake. The retreat has slowed since 1999 after the lake narrowed at the westward turn. Retreat will continue as a snowline at 1000 m is to high to sustain even the current size of Palma Glacier.

1986 Landsat image

1999 Landsat Image

2014 Landsat Image

2015 Landsat Image

Bionnassay Glacier Terminus Tongue Detaches, Mont Blanc, France

On September 24, 2015May 2, 2024 By mspeltoIn france glacier retreat, glacier climate change, Glacier Observations, Uncategorized

Bionnassay Glacier drains west from Dôme du Goûter and Aiguille de Bionnassay of the Mont Blanc Massif in France. The glacier has a heavily debris covered terminus and has experienced less retreat from 1980-2010 then other Mont Blance glaciers. Bionnassay retreated 200 m (Moreau et al , 2012), while Mer de Glace retreated 500 m in the interval 1998 to 2008. Gardent et al (2014) observed a 25% decline in the area of glaciers in the French Alps from 1970 to 2009, with the rate increasing significantly recently. Bionnassay is now in rapid retreat as the stagnant terminus tongue is detached from the active glacier tongue.

Bionnassay Glacier. Red arrow indicates terminus of stagnant region. Yellow arrow indicates bedrock emerging that is separating stagnant terminus tongue. Green arrow indicates lower limit of active glacier.

In 1985 the glacier terminus is at the yellow arrow. The debris covered ice is crevassed and covers the entire region at the red and green arrow. Points B and C are ice covered and Point A has a small exposure of bedrock. In 1999 retreat from the yellow arrow is evident the glacier still covering the region at the red and green arrow. In 2001 Google Earth image the terminus is evident at the red arrow, the region at the green and yellow area are covered by glacier ice. In 2011 the terminus has retreated 180 m since 2001, bedrock has emerged at the green arrow, beginning to separate the stagnant debris covered terminus tongue. At the yellow arrow the crevassing has diminished greatly. In 2015 the terminus has retreated to the pink arrow. Bedrock has been exposed from below the glacier terminus tongue at the yellow arrow. The active glacier terminus is now at the green arrow. At Point B and C glacier thinning has led to marginal retreat and exposure of bedrock where there was glacier ice. At Point A the expanse of exposed bedrock has greatly expanded. The retreat of the main glacier terminus is around 200 m. However, the retreat to the newly emergent bedrock separating the glacier is 750 m. The active terminus is now 1700 m from the 1985 terminus position at the green arrow. In the next few years this will become a well defined terminus, as the lower stagnant zone melt away.

Bionnassay Glacier is just south of Taconnaz Glacier, which is also retreating.

1985 Landsat image

1999 Landsat image

2001 Google Earth Image

2011 Google Earth Image

2015 Landsat image

500 m

Acodado Glacier, Chile Rapid Retreat 1987-2015

On September 21, 2015May 2, 2024 By mspeltoIn chile glacier melt, chile glacier retreat, climate change glacier retreat, glacier climate change, Glacier Observations

Landsat image comparison 1987 and 2015
Loriaux and Casassa (2013) examined the expansion of lakes of the Northern Patagonia Ice Cap. From 1945 to 2011 lake area expanded 65%, 66 square kilometers. Rio Acodado has two large glacier termini at its headwater, HPN2 and HPN3. that are fed by the same accumulation zone and comprise the Acodado Glacier. The glacier separates from Steffen Glacier at 900 m. The lakes at the terminus of each were first observed in 1976 and had an area of 2.4 and 5.0 square kilometers in 2011. (Loriaux and Casassa, 2013). Willis et al (2012) noted a 3.5 m loss per year from 2001-2011 in the ablation zone of the Acodado Glacier, they also note annual velocity is less than 300 m/year in the ablation zone. Davies and Glasser (2012) noted that the Acodado Glacier termini, HPN2 and HPN3, had retreated at a steadily increasing rate from 1870 to 2011. Here we examine the substantial changes in Acodado Glacier from 1987 to 2015 using Landsat imagery.
Digital Globe image of Acodado Glacier and the termini HPN2 and HPN3.

In HPN2 terminates at the red arrow in 1987 and HPN3 at the yellow arrow, the snowline is at the purple dots at 1000 m. By 2000 the glacier has retreated from the red and yellow arrow by 400 m and 900 m respectively, and the snowline is at 1100 m. In 2014 there are many large icebergs in the lake at the terminus of HPN3, these are from recent calving retreat. This is not an area where the lakes develop even seasonal lake ice cover. The snowline is again at 1100 m. In 2015 it is apparent that HPN2 has retreated 2100 m from the red arrow to the pink arrow. HPN3 has retreated 3200 m from the yellow to the orange arrow. The snowline is again at 1100 m. The retreat accelerated after 2000 for both glaciers. This high of a snowline indicates warm temperatures generating high ablation rates, which will lead to more retreat. HPN3 has a sharp rise in elevation 2.5 km above the terminus, before it joins the main Acodado Glacier, it should retreat rapidly toward this point and then calving will end and retreat will slow. The retreat here is synonymous with the pattern observed at other Northern Patagonia Ice Cap outlet glaciers each with rapid calving retreats in expanding proglacial lakes; Fraenkel Glacier, Gualas and Reichert Glacierand Steffen Glacier.

Landsat image from 1987

Landsat image from 2000

Landsat image from 2014

Landsat image from 2015

Fraenkel Glacier Retreat, Patagonia, Chile

On September 17, 2015May 2, 2024 By mspeltoIn chile glacier melt, chile glacier retreat, glacier climate change, Glacier Observations

Fraenkel Glacier drains the west side of the Northern Patagonia Ice Cap (NPI) just south of Glaciar San Quintin. The retreat of this glacier in the last 30 years mirrors that of Gualas and Reichert Glacier, which also terminate in an expanding proglacial lake. Davies and Glasser (2012) work, had an excellent Figure indicating two periods of fastest recession since 1870, are 1975-1986 and 2001-2011 for NPI glaciers. They noted the loss was 0.07% from 1870-1986, 0.14% annually from 1986-2001 and 0.22% annually from 2001-2011. Willis et al (2011) observed that the thinning rate of NPI glaciers below the equilibrium line has increased substantially from 2000-2012. On Fraenkel Glacier they observed a 2.4 m per year thinning in the ablation zone. Here we examine the changes in this glacier from 1987 to 2015 using Landsat Image.

In 1987 the glacier terminus was at the end of a peninsula red arrow and the proglacial lake it terminates in is 2 km long. There is a medial moraine on the glacier at the yellow arrow and the glacier covers the terrain below an icefall at the purple arrow. By 2000 at the purple arrow bedrock is appearing from the base of the glacier. The medial moraine at yellow arrow is little changed. The terminus has retreated 800 m. By 2015 the area around the purple arrow has been deglaciated emphasizing the amount of thinning in the ablation zone even well upglacier of the terminus. At the yellow arrow the medial moraine has been replaced by a wide rock rib separating the glacier from a former tributary. The main terminus is at the pink arrow, indicating a retreat of 1.4 km since 1987. The retreat rate of 50 meters per years though large is less than on Reichert Glacier or Gualas Glacier. Mouginot and Rignot (2014) observe that Fraenkel Glacier does not have the high velocity of the neighboring Benito and San Quintin Glacier or the Gualas and Reichert Glacier, this leads to the potential for greater mass loss of the ablation zone and even faster retreat.

Fraenkel Glacier Landsat Image 1987

Fraenkel Glacier Landsat Image 2000