Deming Glacier Icefall Decline

On May 21, 2012May 24, 2012 By mspeltoIn Glacier Observations4 Comments

This is the first of two posts focusing on Deming Glacier and will focus on the Deming Glacier Icefall, the next on the Deming Glacier terminus. The glacier drains from the southwest side of the summit of Mount Baker a stratovolcano in the North Cascades of Washington, with a massive icefall feeding the lower valley terminus reach of the glacier.The icefall begins at 2200 meters and descends to 1600 meters. The glacier feeds the Middle Fork Nooksack River which provides some of the water supply for Bellingham, WA. I first observed the Deming Icefall from the terminus area of the glacier in 1987. This visit demonstrated that it is not safe to hike to the terminus of this glacier each year. In 1990 we began annual observation of Deming Glacier. Each summer we monitor the adjacent Easton Glacier in detail as the surrogate for Deming Glacier, which is dangerous and difficult to work on. Annual observation of the change in areal extent of the Deming Glacier with elevation combined with mass balance assessment on Easton Glacier provides an annual assessment of the meltwater provided by the glacier to the Nooksack River system. The glacier advanced from 1950-1980, and has retreated since 1980. The icefall transitions the glacier from the accumulation zone to the ablation (melt) zone at the bottom of the icefall. Above the icefall at 2400-3000 meters the average snow depth left at the end of the summer based on several thousand crevasse stratigraphy measurments is 2.75 meters. The icefall sweeps around a bedrock with an east and a west arm splitting above and rejoining below the knob. In particular the east arm has experienced significant reduction in width and velocity.The sequence below starts with an Austin Post photograph from 1979, that illustrates the east arm, the west arm is hidden. The east arm has the same width descending the step of the icefall. This is followed by the icefall in 1988, the red arrow indicates a rib that begins to extend across the east arm as the glacier thins.
The rib continues to extend across the east arm as noted from our observations of the glacier from an observation point adjacent to the icefall. Views from this location from 2003, 2005, 2007, 2009 and 2011 are shown in that order below. .
The next sequence examines the change in the icefall from Google Earth annotated imagery. The sequence begins with the 1984 map, the east arm is a nearly uniform 400 m in width. The sequence continues with 1993 and 2009. The red path is from 1993, and the blue path from 2009. In 1984 there is no bedrock rib, by 1993 it has begun to form but extends only 75 meters, by 2009 it extends 150 meters and by 2011 175 meters across the east arm. The width of the east arm has been reduced from 400 meters to 150 meters from 1984-2011. The sequence also indicates the lateral reduction in width after the two glaciers join at the base of the icefall from 1984 to 2009. In 1984 the glacier was 425 meters wide and in 2009 is 225 meters wide.

West Barun Glacier Retreat Lake Expansion, Nepal

On May 18, 2012June 20, 2014 By mspeltoIn Glacier Observations4 Comments

The West Barun Glacier flows southwest from Baruntse Peak at 7100 meters ending at Barun Khola (lake) at 4500 meters. Comparison of images from 1992, 2003 and 2009 indicate the retreat of the glacier and expansion of the lake. In the early 1990’s the lake was observed to be 1100 meters long with an area of 0.66 square kilometers (ICIMOD, 2010). In 2003 the lake was 1500 meters long. In 2009 the lake was 2000 meters long and had an area of 1.4 square kilometers having doubled in size. In 2013 the maximum length of the lake is 2700 m and the area 1.5 to 1.6 square kilometers. The importance of such lakes impounded in part by moraines, is the potential for glacier lake outburst floods (GLOF). The Barun Khola has no specific date for a GLOF observed, but does pose a risk and has produced floods as indicated by Pradeep Mool (2001) in Figure 1 of the ICIMOD (2010) report, reproduced here, Band C are Barun Khola. ICIMOD has examined this hazard extensively in Nepal and particularly the Dudh Khosi Basin. To date the Dudh Khosi does not have main stem hydropower, but a 210 MW plant is in development. An examination of Landsat imagery from 1992 and 2009 along with Google Earth imagery from 2003 and 2009 is used to identify the retreat. The red line in the Google earth images is the 1992 terminus, the orange line the 2003 terminus and the green line the 2009 terminus. The glacier is outlined in magenta in the Landsat images. The glacier retreated 270 meters, 25 m/year), from 1992 to 2003. From 2003 to 2009 the glacier retreated an additional 480 meter, 80 meters per year. In the 2013 Landsat image the southern portion of the terminus has not markedly retreated since 2009, but the lake expansion continues on the northern shore of the lake., pink arrow.
1992 Landsat image

2003 Google earth image

2009 Google Earth image

2009 Landsat image

2013 Landsat image

A closeup view of the terminus from Google Earth indicates lots of icebergs near the ice front, magenta arrows. The icebergs in the Landsat image later in 2009 have drifted further from the glacier. The angular nature of the icebergs indicates recent large calving event. There are also some small lakes on the surface of the glacier, yellow arrows.
This glaciers retreat and lake expansion is like the nearby North Lhonak Glacier, Middle Lhonak Glacier, Imja Glacier and Nobuk Glacier.

Eel Glacier, Retreat Olympic Mts., Washington

On May 14, 2012 By mspeltoIn Glacier Observations

The Eel Glacier flows north from the Mount Anderson massif in Olympic National Park. This post examines imagery of the glacier from 1961, 1990 and 2009. The glacier has retreated 180 meters from 1990 and 2009, approximately 10 meters/year. The retreat rate has accelerated from the 5 meters/year from 1960-1990. The glacier has lost half of its area since first photographed in 1927 (NPS). What is of greater concern than the terminal retreat is the upglacier thinning during this period. In 1990 the glacier was receiving considerable contributions from the east and west slope of the mountain, near blue arrows. By 2009 the main glacier is nearly separated from the flow from the east and west valley sides. There has been considerable expansion of the blue arrows of bare rock areas that had been underneath glacier ice in 1990. The orange line is 1990 terminus, green line 2009. The loss of connection indicates thinning high up on glacier, that changes the very nature of the glacier from 1960 (top image) to 2009 (bottom image), the blue line is the 1960 terminus. . The retreat of this glacier is less severe than Anderson Glacier just over the pass, and is more like that of White Glacier. The mass loss follows that of North Cascade glaciers where thinning on most glacier has occurred from the terminus to the top of the glacier.

South Lhonak Glacier, Retreat Sikkim

On May 8, 2012February 8, 2013 By mspeltoIn Glacier Observations

The South Lhonak Glacier drains east from Lhonak Peak into Sikkim from the Nepal-Sikkim border. The glacier begins at the border at 6500 meter and ends in a lake at 5200 meters. In 1933 the Mount Everest Expedition led by Eric Shipton explored the area. They traversed across the border and down the Lhonak Glacier finding only moraine covered cover glacier and no lake. Comparison of Landsat and Google Earth images from 2000-2011 indicate the expansion of the lake as the glacier has retreated. The first three are Landsat images from 2000 (top), 2010 (middle) and 2011 (bottom), indicating the expansion of the lake and glacier retreat. 2013 Update A paper just published in Current Science by K. Babu Govindha Raj1, S.N. Remya andK. Vinod Kumar reports on this lake expanding by 1.9 km due to glacier retreat from 1962-2008.

The next set of three are from Google Earth with a Landsat image from 2000 overlain in GE (top), 2006 GE image (middle) and 2010 GE image (bottom). The 2010 terminus is marked by green line, 2006 orange line and 2000 magenta line. The glacier retreated 350 meters from 2000 to 2006 and 250 meters from 2006-2010. The net 600 meter retreat for the decade is 60 m/per year. The 2006 image has red arrows indicating the large moraine behind which the lake has formed, and which Shipton found the glacier pressed up against. The retreat from 1933-2010 is at least 1800 meters. Clearly the retreat in the last decade is much more rapid than previous. The specific hazard is identified by Babu Govindha Raj et al (2013), the lake outburst probability is a very high value of 42% and peak discharge estimated at 586 m3/s. The retreat fits the pattern of other glaciers in the area reported by Raina (2008) and including Zemu Glacier and Changsang Glacier. In Sikkim 26 glaciers examined were retreating at an average rate of 13.02 m per year from 1976 to 2005. An example of this kind of retreat from Bhutan is Theri Kang Glacierand Changsang Glacier in Sikkim is another example.
A closeup examination of the terminus region of the Lhonak Glacier indicates a well incised supraglacial stream (on surface of glacier), indicating relative stagnation. Three areas where debris cover has protected the underlying ice leading to a prominent ridge on the glacier,(light blue arrows) again an indicator of stagnation. Finally the magenta arrow identifies a side stream valley that adjacent to the glacier and lower than the glacier, another indication of stagnation.

Index of Glacier posts June 2009-May 2012

On May 6, 2012May 6, 2012 By mspeltoIn Glacier Observations

Glacier Index List
Below is a list of the individual glacier posts examining our warming climates impact on each glacier. This represents the first 2.7 years of posts, 192 total posts, 180 different glaciers. I have worked directly on 41. The others are prompted by fine research that I had come across, cited in each post or inquiries from readers and other scientists. I then look at additional often more recent imagery to expand on that research. The imagery comes either from MODIS, Landsat, Geoeye or Google Earth.

New Zealand
Tasman Glacier
Murchison Glacier
Donne Glacier
Mueller Glacier, NZ
Gunn Glacier, NZ

Africa
Rwenzori Glaciers
Tyndall Glacier, Kenya

Himalaya
Ngozumpa Glacier, Nepal
Samudra Tupa, India
Zemu Glacier, Sikkim
Theri Kang Glacier, Bhutan
Zemestan Glacier, Afghanistan
Khumbu Glacier, Nepal
Imja Glacier, Nepal
Gangotri Glacier, India
Milam Glacier, India
Satopanth Glacier, India
Kali Gandaki Headwaters, Nepal
Menlung Glacier, Tibet
Boshula Glaciers, Tibet
Urumquihe Glacier, Tibet
Sara Umaga Glacier, India
Dzhungharia Alatau, Kazakhstan
Petrov Glacier,Kyrgyzstan
Hailuogou Glacier, China
Reqiang Glacier Retreat, Tibet
Himalaya Glacier Index

Europe
Taconnaz GLacier, France
Mer de Glace, France
Dargentiere Glacier, France
Grand Motte and Pramort Glacier Tignes Ski area, France
Saint Sorlin, France
Sommelier Glacier
Obeeraar Glacier, Austria
Ochsentaler Glacier, Austria
Pitzal Glacier, Austria
Dosde Glacier, Italy
Maladeta Glacier, Spain
Presena Glacier, Italy
Triftgletscher, Switzerland
Rotmoosferner, Austria
Stubai Glacier, Austria
Hallstatter Glacier, Austria
Ried Glacier, Switzerland
Cavagnoli Glacier, Switzerland
Chuebodengletscher and Ghiacciaio-del-Pizzo-Rotondo
Forni Glacier, Italy
Careser Glacier, Italy
Peridido Glacier, Spain
Engabreen, Norway
Midtdalsbreen, Norway
Tunsbergdalsbreen, Norway
TungnaarJokull, Iceland
Langjökull, Iceland
Gigjokull, Iceland
Skeidararjokull, Iceland
Kotlujokull, Iceland
Lednik Fytnargin, Russia
Rembesdalsskaka, Norway
Irik Glacier, Mount Elbrus, Russia

Greenland and European Arctic
Mittivakkat Glacier
Ryder Glacier
Humboldt Glacier
Petermann Glacier
Kuussuup Sermia
Jakobshavn Isbrae
Umiamako Glacier
Kong Oscar, Glacier
Upernavik Glacier
Epiq Sermia
Sortebrae Glacier, Greenland
Severnaya Zemlya, Russian Arctic
Hansbreen, Svalbard
Nannbreen, Svalbard
Hornbreen and Hambergbreen, Svalbard
Albrechtbreen, Svalbard
Roze and Sredniy Glacier, Novaya Zemyla
Nizkiy and Glazova Glacier, Novaya Zemyla

South America
Colonia Glacier, Chile
Artesonraju Glacier, Peru
Nef Glacier, Chile
Tyndall Glacier, Chile
Alemania Glacier, Chile
Zongo Glacier, Bolivia
Sierra Nevade del Cocuy Glaciers, Colombia
Llaca Glacier, Peru
Arhuey Glacier, Peru
Seco Glacier, Argentina
Onelli Glacier, Argentina
Quelccaya Ice Cap, Peru
Glacier Gualas, Chile

Antarctica and Circum Antarctic Islands
Pine Island Glacier
Fleming Glacier
Hariot Glacier
Smith Glacier, Antarctica
Amsler Island
Stephenson Glacier, Heard Island
Neumayer, South Georgia
Ampere, Kerguelen
Cook Ice Cap, Kerguelen Island
Nordenskjold Coast, Antarctic Peninsula
Prospect Glacier, Antarctic Peninsula
Ross Hindle Glacier, South Georgia
Vega Island Ice Cap
Rohss Bay, James Ross Island, Antarctica

North Cascade Glacier Climate Project Reports

Forecasting Glacier Survival
North Cascade Glacier Mass Balance 2010
Columbia Glacier Annual Time Lapse
North Cascade Glacier Climate Project 2009 field season
28th Field Season Schedule of the North Cascade Glacier Climate Project
North Cascade Glacier Climate Project 2011 Field Season
BAMS 2010
2011 Glacier mass balance North Cascades and Juneau Icefield
Taku Glacier TSL Paper

Sierra Nevada del Cocuy Glacier Retreat, Colombia

On May 3, 2012 By mspeltoIn Glacier Observations

The Sierra Nevada del Cocuy is the second largest concentration of glaciers in Colombia. The glaciated area in Colombia is at 6º27′ N and 72º18′ W and extends along the crest of this range. Morris et al (2006) documented the decline in total area from 39.1 square kilometers to 16.3 square kilometers in 2003. Poveda and Pineda (2009) estimated glacier area of as 28.6 km2 in 1989, 22.9 km2in 2000, and 17.00 km2 in 2007. A 40% decline in area in two decades. This post examines Landsat images from 1988 and 2012 and a Geoeye image from 2010. In the first image from 1988 identifies key local geographic localities, Laguna Grande de la Sierra (LGS), Laguna Grande de la Plaza (LGP), Concavo (C) Pulipito del Diablo (PD). The purple arrow indicates the separation of the main ice mass on PD from the arm extending north in 2010 (middle) and 2012 (bottom). The yellow arrow indicates the retreat of the glacier descending from Concavo toward LGS, from 1988 to 2012 the retreat has been 300 meters from 1988 to 2012. The glacier has declined from 1500 meters to 1200 meters in length. The red arrows indicate the separation of the Concavo glaciated summit and the arm of the glacier that extended to the north. What we see is the separation of a continuous ice mass along the crest of the Sierra del Concuy. Poveda and Pineda (2009) ask whether the glaciers will disappear during the 2010-2020 decade. Glaciers disappear because they lack a consistent and persistent accumulation zone (Pelto, 2010), we cannot just extrapolate onn glacier area decline. In this case the losses indicate continued segmentation and separation, but clearly there are several key areas that have substantial area and will not disappear within the decade. There is insufficient data to identify if any of the glacier retain sufficient snowcover to be sustained with current climate.

Albrectbreen, Svalbard retreat and thinning

On April 30, 2012 By mspeltoIn Glacier Observations

Albrechtbreen is a glacier draining the northeast side of the Edgoya Ice Cap. James et al (2012) report that the glacier retreated at a rate of 33 m/year from 1971-2000 and 64 m/year after 2000. The glacier terminates on an outwash plain at 50 meters, and begins from the ice cap at 300 meters. From 1971-2005 the ice cap has had a mass balance loss of -0.6 m/year (Nuth et al, 2010). The Albrechtbreen has had a more negative mass balance losing 34 m in thickness, essentially 1 m/year (James et al, 2012). The thinning has not been isolated to the margin of the glacier, with the greatest thinning occurring at 150 meters. The retreat and thinning is identified in the Figure from James et al (2012). In this post Landsat imgery from 2002, 2005 and 2010 is utilized to identify marginal changes and upglacier thinning. The blue dots in each image indicate the snowline, the yellow arrow a distinctive lake beyond the terminus that can be used to gage the retreat from 2002 to 2010, and the blue and violet arrows indicate locations where bedrock exposure has expanded as the glacier has thinned. The terminus in the vicinity of the lake has retreated 450 meters in eight years, 55 meters/year. . That the thinning extends to the highest areas of the Albrectbreen is not a good sign for its long term survival. The lack of snowcover can be a bit deceiving since much of the accumulation on this glacier is superimposed ice. That is meltwater that is refrozen before escaping the glacier.

Smith Glacier Thining, Rifting, Retreat, Antarctica

On April 26, 2012April 26, 2012 By mspeltoIn Glacier Observations2 Comments

Smith Glacier, West Antarctica is two glaciers to the west of Pine Island Glacier flowing into the Crosson Ice Shelf in the Amundsen Sea. Pine Island Glacier (PIG) has been the focus of more extensive study because of its size and its identification as the weak underbelly of the West Antarctic Ice Sheet. Two recent papers have focused on changes on glaciers in the region. Pritchard et al (2009) identified thinning over almost all of Smith Glacier, thinning near the grounding line and on the floating ice shelf has been 9 m/year from 2003-2007, somewhat more than PIG, top image. Smith Glaciers floating section the Crosson ice Shelf northwestern margin is buttressed by the Bear Peninsula. Since 1984 MacGregor et al, (2012) identified increased rifting and detachment from the peninsula. The peninsula has been a pinning point, detachment can lead to destabilization of the ice shelf. They further identified a 24 km retreat of the terminus since 1990 and a reduced area of attachment and increased rifting near Mount Murphy. The terminus position change is seen in the second image below. The light blue color is 1984 and the red colors are the 2007 and 2011 terminus position, In this post we look at the detachment from the Bear Peninsula. Like on PIG Smith Glacier has accelerated by 500 m/year, nearly doubling its velocity. The loss of buttressing and reduced size of the ice shelf reduces back forces that would allow acceleration. Point A marks the location where attachment is in 2011, Point B marks an area of attachment between the Crosson ice Shelf and the Bear Peninsula in 1999 (top image below) and 2002 (second image). By 2011 (bottom two images) this area around B is not attached and also has expanded rifting.

The entire Crosson Ice Shelf is threatened by rifting near Mount Murphy (blue arrows above and green arrows below) that were noted by MacGregror et al (2012). The rifting has expanded in number and extent from 2011 above to 1999 below. The entire ice shelf with acceleration shows considerable rifting, which combined with thinning has been a recipe for destabilization and breakup of ice shelves on the Antarctic Peninsula, such as at Wilkins Glacier, Fleming Glacier and Prospect Glacier. The thinning has been noted as widespread around most of Anarctic Ice Shelves in a paper this week from Pritchard et al (2012). This paper from an international team from British Antarctic Survey, Utrecht University, Scripps Institution of Oceanography and Earth & Space Research has identified the losses are principally the result of increased basal melting from intrusion at depth of warm water. In the Smith Glacier area there is no significant surface melting, so basal melting must be the source.

Romanzof Glacier Retreat. Brooks Range, Alaska

On April 22, 2012April 22, 2012 By mspeltoIn Glacier Observations

In the Romanzof Mts. Brooks Range, Alaska McCall Glacier and Okpilak Glacier have been the main focus of research. These glaciers are much smaller than glaciers in southern Alaska, as the region has much more limited amounts of snowfall. The University of Alaska-Fairbanks have focused on McCall Glacier average rate of thinning increased between 1956–93 and 1993–2002, averaging 0.4 m/year for the entire period. The primary region of thinning was the lower third of the glacier below 1700 meters (Nolan et al, 2005). The glacier had retreated 800 meters from the Little Ice Age moraine by 2000 (Nolan et al, 2005). The Equilibrium Line Altitude has risen from 2050 in the 1970’s to 2250 m recently, leading to continued and more rapid losses in ice volume (Delcourt et al, 2009). Okpilak Glacier had retreated 2 km from its Little Ice Age moraine by 2006.

In this post we examine the Romanzof Glacier. The first image indicates the various tributaries feeding into the main valley glacier, burgundy arrows, the reach of well developed stream channels, green arrows. The red line is the map terminus and the yellow line the 2009 terminus. The map is the USGS topographic map from 1956 aerial photographs This glacier has retreated 1300 meters from its 1956 mapped position and 1900 meters from its Little Ice Age moraine, blue line in first image below. The glacier remains 5 km long, having lost 25% of its length in the last 50 years. The rate of ice loss like on McCall Glacier has accelerated. A view of the middle of the ablation zone indicates some well developed stream channels, green arrows. Channels like this take multiple years to form and indicate limited glacier velocity. Closer to the terminus the stream channels are even larger, green arrows. The streams have matured developing meanders, this tends to occur only where the surface is stagnant. This indicates the lower 1200-1500 meters of the glacier is stagnant and melting away quickly. In addition there are some ridges of ice cored moraine indicating that the bare ice is melting faster than the ice under the moraine debris, violet arrows. The bluish arrows indicate where the subglacial streams have emerged from beneath the ice indicating the terminus.

Nizkiy and Glazova Glacier Retreat Novaya Zemlya

On April 18, 2012April 2, 2013 By mspeltoIn Glacier Observations

The glaciers of northern Novaya Zemlya, Russia are truly generally out of sight out of mine. There remoteness and lack of importance as a water resource being the key reasons. A recent study by LEGOS (Laboratoire D’Eetudes en Geophysicque et Oceanographie Spatiales) in France highlights the changes of these glaciers from 1990-2000. It seems particularly important to pay attention to these glaciers due to the recent changes in sea ice cover that have left a much longer duration of open water around the island particularly to the west in the Barents Sea. This has been beautifully illustrated in a post at Arctic Sea Ice Blog this week. . Here we focus on two glaciers, Nitzky and Glasova on the west coast of the island that LEGOS identified as losing 1.2 and 1.4 square kilometers in area from 1990-2000 LEGOS (Alexei Kouarev, Frédérique Rémy and Benoit Legresy) a. Here we compare a Landsat image from 1988 and 2009. The northern glacier of the two is Glazova, the burgundy arrows and dots indicate the terminus in 1988. In the 2009 image the terminus is orange dots. Glazova Glacier has retreated 1500 meters. The Nizkiy Glacier has several termini in lakes and one in the Barents Sea. Along the northern margin inland of the terminus in 1988 the green arrow indicates a proglacial lake, trapped by the glacier. In 2009 the lake has drained, green arrow and the green dots indicate the path by which the lake drained. Marginal retreat of 500 meters opened up a passage for drainage. The main terminus juts north out beyond the end of a peninsula, by 2009 the terminus has retreated 1000-1500 meters enough to leave this terminus exposed, note the burgundy dots on both images. The middle terminus ends in a proglacial lake and in 1988 the terminus largely envelops an island, yellow arrow. By 2009 the glacier has exposed almost all of this island a 1000 meter retreat. The southernmost terminus shown is indicated by a black arrow. In 1988 the piedmont lobe of this glacier almost completely fills the lake basin. In 2009 the lake basin is half exposed by glacier retreat, this is a 1500 meter retreat. The very map of the region is changing. Below is the 1988 and then 2009 image. After we will zoom in and further discuss the changes on Nizkiy Glacier. .
The yellow arrow indicates the new island forming in the proglacial lake, burgundy arrow indicates the peninsula that the main marine terminus extended beyond in 1988 and the green arrow indicates the edge of the valley through which the formerly trapped lake could drain. It will likely be quite soon when the proglacial lake with the island joins with the Barents Sea. This region has quite limited Landsat imagery making it hard to determine how much retreat occurred in 2011. The last image is a MODIS image from 8/31/2011, where the burgundy arrow indicates the peninsula at the end of Nizkiy Glacier. This retreat fits the pattern of retreat and changes in geography from retreat further NE in Novaya Zemlya at Roze and Sredniy Glacier and elsewhere on the northwest coast, Krivosheina Glacier.

Alemania Glacier Retreat, Lago Martinic expansion-contraction, Chile

On April 15, 2012December 29, 2014 By mspeltoIn Glacier Observations

The Cordillera Darwin in Tierra Del Fuego Chile is a remote area. GLIMS (Glacier Land Ice Monitoring from Space) which has an inventory of glaciers showing at least size and boundaries, has nothing for this region in 2012. The USGS in their publication on South American glaciers just notes the lack of satellite imagery for assessing these remote glaciers. Chile is currently undertaking an inventory of these glaciers. The Alemania Glacier (Roncagli) is the focus of this post, the glacier can be seen from the Beagle Channel. The focus is not main terminus, but the terminus that ends in Lago Martinic (LM). In Google Earth imagery imagery this lake is trapped by the Alemania Glacier. There are two smaller glacier draining into the west end of the lake and Alemania’s secondary terminus ends in the lake. The red arrow points to the terminus, the green arrow to a nunatak near the Lago Martinic terminus and the yellow arrow to a developing nunatak upglacier, AT indicates the main terminus of the Alemania Glacier. The next three images are all from Landsat and indicate some spectacular changes from 2000 top image, 2008 middle image and 2011 bottom image. From 2000 to 2008 the Lago Martinic terminus of the glacier retreat 1300 meters, reaching the nunatak by 2008, this represents a significant expansion of the lake. In 2011 the terminus has retreated little but the lake has drained to an extent exposing the pink areas of the former lake bottom. In the future this maybe a lake that periodically fills in the Austral Spring and drains later in the Austral summer. The main terminus of the Alemania Glacier also exhibits a notably developing lake at the terminus compared to 2000, more on this below. The upglacier nunatak, yellow arrow, has also become more exposed indicating glacier thinning. A closeup of the main terminus of the Alemania indicates a 500 meter retreat of the east side of the glacier from the 2000 GE imagery to the 2011 Landsat imagery. The lake at the terminus has become significant, this should speed retreat in the near future. Though further south than the large Patagonia Icefields the glacier changes mirror those of the main icefields, Colonia, Tyndall, Gualas that are being intensively investigated by the Chilean Laboratorio de Glaciologia

Cook Ice Cap Northern Outlet (Aggasiz Glacier) Retreat, new lake born Kerguelen Island

On April 12, 2012April 27, 2014 By mspeltoIn Glacier Observations

Kerguelen Island sits alone at the edge of the furious fifties in the southern Indian Ocean. The island features numerous glaciers, the largest being the Cook Ice Cap at 400 square kilometers. A comparison of aerial images from 1963 and 2001 by Berthier et al (2009) indicated the ice cap had lost 21 % of its area in the 38 year period. Le Bris et al (2008) in a related part of the aforementioned study noted that the retreat accelerated after 1970 and again after 2003, with thinning of 5 meters/year on Ampere Glacier and retreat of 75 m/year on Explorer Glacier on the east side of the ice cap. In this post we focus on the largest outlet glacier flowing north from the ice cap, Agassiz Glacier. A comparison of Google Earth (top), 2001 (middle) and 2011 (bottom) Landsat images indicate a significant retreat and formation of a new lake that is not evident in maps or Google Earth imagery. The red arrows point to the glacier tongue and in the 2011 image the black arrow indicates the new lake. Agassiz Glacier has lost its field hockey stick shaped hook and has retreated 2 km in just 10 years, the rate of 200 m/year is quite high even by Cook Ice Cap standards. The glacier is calving into the lake which can accelerate retreat. The terminus does not appear to be at a stable point, with a wide calving front in comparatively deep water. The retreat of this glacier fits the retreat of other glaciers on islands in the Southern Ocean, Arago Glacier, Stephenson Glacier, Neumayer and Ross Hindle