Penny Ice Cap southwestern margin retreat

On February 20, 2012 By mspeltoIn Glacier Observations1 Comment

Examination of 1991 and 2009 Landsat imagery highlights the retreat of the Penny Ice Cap at its southwestern margin. The glaciers and lakes in this region are unnamed. The Penny Ice Cap is one of two large ice caps on Baffin Island and is the southernmost of the two, with an area of more than 5600 square kilometers. On the east side the glacier exit the ice cap through spectacular mountains. The westside spreads across rolling upland terrain. In this post we examine the margin at the southwest corner, where the ice cap ends in a series of upland lakes. Changes in the margin are identifed from Landsat images from 1991-top, 2003-middle and 2009-bottom. The snowline in this region is near 900 meters in the 1991 and 2003 images. In the 2009 image the snowline is at least 1100 meters leaving the southwest corner of the Penny Ice Cap with a minimal accumulation zone. Zdanowizc et al (2012) note that in recent years the ice cap has experienced heightened melt and that little retained snowpack survives the summer, that most of the retained accumulation is refrozen meltwater (superimposed ice). In each image key locations are indicated: the nunataks are marked with violet arrows as is the margin downstream of the nunataks, key islands and peninsulas are noted with green arrows that are at the 1991 margin, the orange arrow indicates a region just east of a key marker lake. Landsat imagery from 2003 and 2009 indicates the same locations. It is evident that new islands, lakes and peninsulas are developing. The retreat and formation of new lakes at the orange and violet marginal arrow are apparent the appearance of new islands in the lakes at the green arrows is also evident. One of the largest marginal changes is downstream of the nunataks. In 1991 the margin here had no notable indent from the rest of the margin and the glacier surface was not notably debris covered. In 2009 the margin has developed a new lake as an indent has formed and the glacier surface has more evident debris. This debris is too thin to insulate the ice underneath and instead will reduce the albedo and enhance melting. The nunatak is also expanding particularly toward the margin. Overlaying the 1991 and 2009 images in Google earth provides comparison of the margin of 1991 to the Google Earth imagery and 2009 imagery. The retreat along this section of the ice cap is 300-400 meters during this 18 year period. The driving force has been an increase in temperature and this has caused mass losses on ice caps throughout the Canadian Arctic (Gardner, et al. 2011) and (Sharp et al, 2011). The mass losses of the Penny Ice Cap are also affecting the eastern margin around Coronation Glacier.

Ngozumpa Glacier Retreat Tongue Disintegration, Nepal

On February 16, 2012February 17, 2012 By mspeltoIn Glacier Observations1 Comment

Ngozumpa Glacier (also Ngozumba) is a large debris covered valley glacier draining south from Cho Oyu and Gyanchung Kang one valley west of the Khumbu valley. The lower kilometers of this glacier is heavily debris covered, similar to the Khumbu Glacier and Imja Glacier. Above image from Doug Benn. From the terminus at 4700 meters to 4900 meters a distance of 8 kilomters the glacier is increasingly riddled with supraglacial lakes (lakes on top of glacier) as this section downwastes. Velocity in this reach is less than 5 meters/year, essentially stagnant. The snowline of the glacier has been at nearly 6000 meters in recent years. On the following image the snowline (blue dots), accumulation areas (A) and terminus blue arrow are indicated. It is evident that more than 50% of this glacier is debris covered. An examination of Landsat imagery from 1992, 2000 and 2009 indicates the expansion of these lakes near the terminus. These lakes (S) in the 2010 (Goggle Earth imagery) are beginning to coalesce and look to be creating a proglacial lake (lake at front of glacier) at the terminus of the glacier. Benn et al (2001) examining the supraglacial lakes hypothesized that the glacier was close to forming a moraine dammed proglacial lake. This is a scenario very similar to what has developed on Menlung Glacier, which is just over the pass into Tibet from the Ngozumpa. Further upglacier the surface of the glacier is riven with more lakes amidst the debris covered relatively stagnant ice. Further upglacier the thinning is evident in the expansion of a bedrock knob in the midst of the glacier (A), the decrease in surface elevation compared to the lateral moraine-trimline (L) and the quite high equilibirum line for 2009 (E). Strong thinning in the accumulation zone, though less than the ablation zone, of Khumbu Glacier was found by Bolch et al(2011)

Speel Glacier Retreat, Coast Range Alaska

On February 9, 2012June 27, 2014 By mspeltoIn Glacier Observations1 Comment

Speel Glacier a 3.2 km retreat from 1984-2013, lake expansion and tributary separation.
In 1984 I had a good chance to observe Speel Glacier while flying into Juneau, AK to work with the Juneau Icefield Research Program on the Juneau Icefield. Speel Glacier is south of the Taku Inelt east of Juneau, Alaska. Unlike the map on my lap, there was now a big lake at the terminus of the glacier. This post examines the retreat of this remote glacier and the expansion of the unnamed lake at its terminus. In 1948 Speel Glacier ended at the head of a braided outwash plain, generated by the Speel River. Upglacier in 1948 there was a lake impounded by the glacier, Speel Lake. Today Speel Lake is gone and a much larger proglacial lake exists. The lower part of the glacier was heavily debris covered and stagnant in 1948. By 1968 the glacier had retreated 1 km just to the edge of the current lake. In 1984 the lake was 2.2 km long. In the images below Landsat 1984, Google Earth 2003, Landsat 2006, Landsat 2009 and 2013, the primary accumulation zone is marked ACC, secondary accumulation areas are indicated by black arrows, the 1984 terminus pink arrow, 2003 terminus blue arrow, 2006 terminus green arrow, 2009 terminus yellow. In the 1984 Landsat image the glacier had retreated 2 kilometers from the 1968 position and was fed by a shared accumulation zone with the Wright Glacier-black arrows in addition to the main accumulation area of the glacier above the main icefall on the east side of the glacier. By 2003 the glacier had retreated 1.9 km to where the lake bends east, and the main tributary from the north separated from the glacier. In the 2006 imagery the glacier has retreated an additional 1.8 km. The connections with the Wright Glacier accumulation area had been lost. The tributary from the north that has its own accumulation zone was now completely separated. The glacier was then solely dependent on a single accumulation zone, ACC. In 2009 the glacier had retreated 200 meters from 2006. By 2013 the glacier had retreated from the lake entirely a 6 km retreat since 1948. This should lead to a reduced rate of retreat.

The rapid retreat of this glacier has reduced its area at low elevation considerably. This is improving the glaciers accumulation area ratio, to be in equilibrium the glacier needs at least 60% of its area to be in the accumulation zone, in this region Pelto (1987) noted that no glaciers in the region were advancing that did not have an accumulation area ration above 67. In 1984 the accumulation area ratio was 48. In 2006 the AAR is 54, ablation area is being lost faster than accumulation area. The icefall marks the boundary between the ablation zone and the accumulation zone.The retreat of this glacier fits the pattern of other glaciers in the region Eagle, Field, Gilkey, and Chickamin. Today the lake averages nearly 1.5 km in width and is over 5 km long.
Landsat imagery 1984

2003 Google Earth image

Landsat imagery 2006

2009 Landsat image

2013 Landsat image- Red arrow is 1984 terminus, purple the 2013 terminus and yellow arrows detached former tributaries.

Severnaya Zemlya Glacier Change, Russia

On February 3, 2012 By mspeltoIn Glacier Observations1 Comment

Severnaya Zemlya is a Russian Island group at the transition from the Kara Sea to the Laptev Sea. This island group is 50 % ice covered, with 18,000 square kilometers of glacier cover. Severnaya Zemlya has been the focus of a detailed remote sensing based study of glacier change by Sharov et al (2010) They observed a mean change in Severnaya glacier thickness of -7.8 m since the 1980’s. The annual rate of ice loss is 4.8 km³/a, a strongly negative net balance. They found that most ice caps have steepened since 1980, Albanov and Dezhnev have both gotten thicker in the center while retreating at the margin. Imagery from this region is scant. The glacier in this region have both small snow accumulation and small melting. Overall most of the ice caps are composed of superimposed ice, that is snow that melted and then refroze before exiting the ice cap. Several ice cores have been drilled through the ice sheets identifying the rate of accumulation through time Klementyev et al (1991) and Kotlyakov et al (2004) the last 8000 years on Vavilov Ice Cap.
First on the Dezhnev Ice Cap thickening of up to 13 m was noted at the top of the ice cap by Sharov et al (2010). In this post we examine a 2000 (top) and a 2010 (middle) Landsat image that shows all of the Dezhnev Ice Cap with the Albanov Ice Cap being half obscured by clouds in the 2000 image. In the Landsat comparison pay particular attention to the region just beneath Points A-C. At Point A we see an expansion of the small proglacial lake. At Point B and C we see exposure of new bare ground as areas of thin ice near the periphery of the ice cap have been lost. In 2010 there is no snow remaining on Dezhnev, however, this by itself does not indicate there was no accumulation that year, as superimposed formation cannot be distinguished from areas of bare ice that experienced ablation in the image. For Albanov Ice Cap there is a modest retreat from the locations noted with arrows that are linear-low spots often sometimes filled with meltwater. In the bottom image a closeup of Dezhneve, an arrow indicates a low spot in the midst of the ice cap that will be prone to melt out. In this image a melt pond has developed there.

Hallstatter Glacier, Austria retreat

On January 28, 2012January 28, 2012 By mspeltoIn Glacier Observations1 Comment

The Hallstatter Glacier (also sometimes called Dachstein Glacier along with the Gosau Glacier) is on the north slope of Dachstein an area of heavy recreational use. The result is good photographic records of glaciers change. This record combined with a recent cooperative project between University of Innsbruck, Blue Sky Weather Analysis and Energie AG Upper Austria provides a good snapshot of glacier change in northern Austria. The glacier begins at 2800 meters and descends to 2200 meters, image below from University of Innsbruck. This project has compiled the annual terminus change of the glacier from 1950-2007, in the image below. The retreat from 1950-1975 averaged 8 meters per year. A period of minor readvance from 1977-1991 occurred, followed by increasingly rapid retreat from 1992-2007 averaging over 10 meters per year in the last decade. Total retreat has been 350 meters from 1950-2007. Over the last century the change is chronicled in the two images, 1900 and 2007, from the Dachstein Project and the 2009 margin is traced in a Google Earth Image, blue line. This project was undertaken because of the importance of the glacier runoff to hydropower production along the Traun and Gosau Watersheds in particular. The change in terminus via mapping from 1969-2002 is evident in the Innsbruck image (2002), the Google Earth image is from 2009. There is thinning particularly of the width of the two main terminus tongues.The mass balance of the glacier has been measured since 2007, every year has had negative balances. In 2011 the snowline was again high, snowpack very limited at the end of the melt season which persisted into October. An Ikonos image from October 2, 2011 indicates that 30-35 percent of the glacier is snowcovered, this is the AAR and it needs to be at 60 for equilibrium.

Northwest Vega Island, Antarctica Glacier Retreat

On January 22, 2012January 22, 2012 By mspeltoIn Glacier Observations1 Comment

Vega Island is a heavily glaciated island just east of the northernmost section of the Antarctic Peninsula (map from Davies et al, 2010 Aberystwyth University). The mass balance of Bahia Del Diablo Glacier (BDD green arrow) located on this island has been monitored by an Argentina research group since 1999/2000 (Skvarca et al 2004 and WGMS, 2010). Nine of these ten years have seen negative mass balances, four substantial losses. The glacier begins at 600 meters and ends at 100 m, with an ELA of 425 meters on average, an image from Pedro Skvarca of Bahia Del Diablo indicates the ice cap nature of the glaciers on Vega Island. Eight kilometers west of Bahia Del Diablo is are three adjacent glaciers at the northwest corner of the island (NW: burgundy Arrow on Vega Map) that is the focus here. In the initial glacier inventory these were listed as glacier 02-04 on Vega Island (Rabassa et al, 1982) This glacier barely reaches to the ocean, but the amount of bare land exposed at the coast along the glacier front is increasing. Further during several recent years this glacier has lost all of its snowcover. This glacier has only a tiny bit of its total area above 400 meters, below the observed ELA of the last decade on Bahia del Diablo. This is an issue for a couple of adjacent glaciers as well. Note the 1999 Google Earth imagery and the Landsat imagery from 2000 that indicate the lack of snowcover, green arrows. In 1999 and 2000 the glacier reached the coast along a distance of 900 meters, red arrows in second image. Note the change in the size of the bedrock exposed near the terminus, burgundy arrow from 1999 to 2011. The glacier frontage by 2011 had been reduced to 250 meters, the bare brown red areas have nearly merged along the coast, soon this glacier will not be reaching the shoreline. The bare rock area between two lobes of the glacier has also expanded, from 1999-2011, burgundy arrows. In 2007 and 2008 there was very little if any snowpack left on this glacier by the end of the melt season. The issue for a glacier without a consistent accumulation zone, is that it will not survive (Pelto, 2010). These glaciers are more like ice caps are not thin and are not melting away quickly. The glacier volume loss is consistent with that observed all around the Antarctic Peninsula, Nordenskjold Coast

Northwest Vega Island, Antarctica Glacier Retreat

On January 22, 2012March 9, 2015 By mspeltoIn Glacier Observations

Sortebrae Retreat, East Greenland

On January 19, 2012 By mspeltoIn Glacier Observations1 Comment

The Sortebrae is a surge type tidewater calving glacier on the Geikie Peninsula of East Greenland. Surge type glaciers do not have a steady ice flow, they have non-steady ice flow where longer quiescent periods of slower flow are punctuated by short periods of faster flow. The glacier is comprised of a number of tributaries (A-D) some of which drain the main Greenland Ice Sheet (E). Sortebrae surged in the 1950’s and 1992-95 (Jiskoot et al, 2001). A diagnostic feature of surging glaciers is the looped or distorted medial moraines (M) that results from the changing degree of contribution of the various tributaries of a surging glacier with time. Not all tributaries surge and if they do it is not necessarily synchronous. The 1992-1995 period featured a 5 km advance, this suggests a periodicity to surging of 4–70 years (Jiskoot et al, 2001). From 2000-2005 the retreat rate was noted as 428 m/year by Jiskoot et al (2012). Comparsion of Landsat images from 2000 (green line) and 2010 (yellow line) indicate a retreat of 5 kilometers, approximately 500 meters/year. Surging glaciers are still sensitive to climate, the surge cycle is an additional factor affecting surface elevation and terminus change. In this region the recent extensive retreat of Sortebrae mirrors that of the other glaciers, Jiskoot et al (2012) identify that just one of 113 tidewater glaciers in the region advanced, and that was during a surge. Average margin retreat rate in terms of area lost increased from 2 square kilometers per year between 1980 and 2000, to 4-5 square kilometers per year from 2001 to 2005..Given the fact that the glacier is not due for a surge in the next couple decades, a continuation of this retreat for even one decade will lead to the separation of the terminus. With the termini entering from the southwest (red arrow) and the main termini (green arrow). The southwestern tributary does not exhibit strong surging features. It is also worth noting quite a few smaller glaciers near the coast here have very limited snowcover remaining (yellow arrow) near the end of the 2010 melt season. This is not a good sign as glacier that do not have consistent accumulation zone will not survive (Pelto, 2010). Given that 2011 also featured limited snowpack it seems to be a too frequent theme for the smaller glaciers in the region. The mass loss of smaller glacier in this region has has been particularly well observed on Mittivakkat Glacier by Mernild et al (2011).

Kennedy Glacier Retreat, Glacier Peak Washington

On January 16, 2012January 16, 2012 By mspeltoIn Glacier Observations1 Comment

At the turn of the century C.E. Rusk explored the glaciers around Glacier Peak that were retreating from their Little Ice Age maximum in the mid-19th century. The average retreat of Glacier Peak glaciers from the LIA to the 1958 map positions was 1640 m. From 1950-1955 Richard Hubley, University of Washington, completed the first aerial glacier surveys of North Cascade termini, noting the beginning of an advance on Glacier Peak that continued up through 1979. All ten glaciers on the slopes of Glacier Peak advanced ranged from 75 to 500 m and culminated in 1978. All 11 Glacier Peak glaciers that advanced during the 1950-1979 period emplaced identifiable maximum advance terminal moraines. A picture of the glacier from R.Luce during this advance shows a glacier with a strongly convex profile. During the 1993-1997 period the North Cascade Glacier Climate Project (NCGCP) surveyed the glaciers around the peak each summer, one century after C.E. Rusk did (Pelto and Hedlund, 2001). By 1984, all the Glacier Peak glaciers were again retreating. This peak even in summer provided some tough weather, including a 1995 August snow storm. Two other glaciers that were a focus of this study around Glacier Peak were Milk Lake, Vista and Honeycomb Glacier.

This post focuses on Kennedy Glacier which is the main glacier draining the west side of the Peak, left glacier in image below. Kennedy and Scimitar Glacier were joined during the LIA descending the Kennedy Creek valley to an elevation of 1315 m. Retreat from the LIA maximum of 1000 m had occurred by the turn of the century. By 1946 the glacier had retreated an additional 700 m to an elevation of 1960 m. In 1952 the glacier was advancing rapidly, as indicated by the 1955 photograph from Richard Hubley of the glacier from 1955. This advance continued up until 1975, the terminus having extended downslope 320 m to terminate at an altitude of 1785 m. By 1984 the terminus had begun to retreat. In 1994 the terminus had retreated 95 m and by 1997 151 m. A view of the terminus in 1993 indicates an active, crevassed terminus tongue, top image. In 1994 (miidle) and 1997 (below) the terminus is a well established vegetation and sediment line marking the 1970’s advance, burgundy arrows. The glacier has continued to retreat, in the 2006 and 2009 Google Earth imagery the orange line is the 1978 terminus, green line 1994, blue line 2006 and red line 2009. The left hand glacier is Kennedy the right hand Scimitar.. The glacier is continuing too retreat, but each summer retains significant accumulation, as evident in the crevasse measurements of snow depths on the upper Kennedy Glacier at 2800 meters. This indicates a glacier that can retreat to a new point of equilibrium with current climate.

Washmawapta Glacier Retreat, British Columbia

On January 13, 2012January 13, 2012 By mspeltoIn Glacier Observations3 Comments

The West Washmawapta Glacier and Washmawapta Icefield are located in the Vermillon Range in British Columbia. They are in a basin between Limestone Peak and Helmet Peak. The West Washmawapta is a cirque glacier and has been the focus of detailed studies of its dynamics and runoff in recent years. The study of its dynamics (Sanders et al, 2010) measured velocities of 3-10 meters/year, pretty typical for a cirque glacier of this size, and had a maximum depth of 185 m, a bit deeper than usual. The runoff study (McGregor, 2007) and Dow et al (2011)examined streamflow below the glacier and found that peak flow was at 2100 hours, several hours after peak melting. They conclude that this indicates a well developed subglacial drainage system. Sanders et al (2010) noted that West Washmawapta Glacier lost 30% of its area from 1949-2007. A comparison of Google Earth imagery from 2002 (top) and 2007 (middle) and Landsat imagery from 2009(bottom) identifies changes in the two glacier in the last decade. For the West Washmawapta Glacier in 2002 the glacier ended in contact with two proglacial lakes (Point A-C) and a lake that is just forming at Point B. The retreat is from 30-50 meters in this five year span. In the 2009 Landsat the Lake at Point C is well separated from the glacier. For Washmawapta Icefield, does not really deserve the icefield title, has lost a lower former glacier section that was in contact with Elizajan Lake, green arrow. The purple areas point to two prominent bedrock features that indicate retreat of 30 meters over the five year time span. The problem for both glacier is the insufficient size of the accumulation area. In 2009 the image is from August 20th, a month left in the melt season and only 40% of the glaciers are snowcovered. An alpine glacier like these needs at least 55% snowcover to be in equilibrium. The 2007 imagery in from July and the accumulation area is at 65%, by September of 2007 the extent was down to 35%. Now if you are still not sated, the video on the West Washmawapta Glacier project illustrates the amount of hard work and good humor that is essential to complete such a field project is quite a treat.

Dzhungharia Alatau, Kazakhstan Glacier Retreat

On January 8, 2012February 2, 2012 By mspeltoIn Glacier Observations

Dzhungharia Alatau range of Kazakhstan is host to over 500 square kilometers of glacier ice. This amount of glacier ice declined by 1% per year from 1956 to 1990, (Severskiy, 2009: 103). This reduction in glacier area parellels that of changes in the Zailiyskiy and Kungey Alatau further south in Kazakhstan and Kyrgyzstan (Bolch, 2006). The Aksu River flows north from the Dzhungharia Alatau into Lake Balkhash. This post focuses on several glaciers in the Aksu River Basin, Eskeldi District, Almaty Province, Kazakhstan. A 2004 Google Earth image highlights the terminus position of several glaciers (A-E) that end in small lakes that are expanding as the glaciers retreat. It is also evident in this image that the snowcovered extent is low. For a glacier to be in equilibrium 55-65% of the glacier needs to be snowcovered at the end of the melt season. In this case the percentage is below 30%. The lakes at point A and C have expanded, and the glacier at point E is no longer in contact with the glacier, in the 2009 Geoeye imagery. The 2009 imagery is after a summer snow storm, that blanketed the glaciers with a thin snowcover. . The amount of retreat of for the 2004-2009 period is close to 140 meters at Point A, 100 meters at Point C and E. A closeup view of the glacier ending at Point A indicates the terminus position green arrow and the outcrops of rock in upper glacier that indicate thinning of the accumulation zone. A glacier with a thinning accumulation zone will not survive (Pelto, 2010). The second image is of the glacier that ends at point C and D and indicates the lack of snowcover on the small glaciers. . Some on the ground photographs of the glaciers in the region from Tsvetik

Petrov Glacier Retreat, Kyrgyzstan

On January 4, 2012January 4, 2012 By mspeltoIn glacier climate change, Glacier Observations

Petrov Glacier flows north down the slopes of Ak-Shiyrak in the Tien Shan Mountains of Kyrgyzstan. The glacier ends in Petrov Lake which continues to expand as the glacier retreats. The glacier is 12 km long has three main tributaries each beginning at 4600-4700 meters and descending to the lake at 3700 meters. The lake in particular has been the focus of an extensive research project by a group Czech scientists, Cerny et al (2009)and Jansky et al (2009). This research for Geomin is driven by interest in a potential outburst flood event, the water level in the Petrov Lake and the moraine-ice dam are monitored and proposals on how to decrease the water level are being developed. Petrov Glacier is the largest glacier in the Naryn River watershed, Jansky et al (2009) report that the glacier retreated at a rate of 24 meters/year from 1957-1960, 40 meters/year from 1980-1999 and 61 m year from 1999-2006. Using two satellite images from 2001 (top) and 2011 (bottom) and Google Earth imagery from 2005 (middle) here we look in detail at the current condition of the glacier. The glacier has retreated 300 meters during the 2001-2011 period. Notice the Peninsula extending from the glacier into Petrov Lake (T). . A snapshot of the glacier at three different locations indicate the extent of the ablation zone. For points A,B and C the red arrow indicates lateral moraines, green arrows surface wind scour features that have trapped dust, and the blue arrows surface streams. Lateral moraines and surface streams cannot exist in the accumulation zone, and the wind scour features indicate locations where accumulation is not retained. Each of these feature types at A,B and C extend to 4300 meters. A glacier such as Petrov that lacks substantial avalanching and is in a region of low annual precipitation generally needs 60% of its area in the accumulation zone to be in equilibrium. The glacier has insufficient accumulation zone size recently and will have to continue to retreat. Petrov Glacier reflects the trends of the region where glaciers have lost 2 cubic kilometers per year of volume from 1955-2000, as documented by Harrison and others, University of Newcastle
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