Gígjökull drains north from the Eyjafjallajökull Ice cap. Eyjafjallajokull began to erupt on March 20. In the initial eruption the fountains of lava were vented from a fissure in a relatively ice free area, east of the ice cap, and did not generate much flooding from ice melt. The vent indicated by NASA from early April has shifted closer to the main ice cap, but is still peripheral to it. The ash plume is also travelling east away from the still white ice cap on April 1. 
In the renewed eruption on April 13-16, 2010 the eruption has shifted closer to the summit of the ice cap melting several holes in the glacier visible in radar imagery from the Icelandic Coast Guard. These are located at the crest and just south of the crest of Gígjökull. The glacier has not been vaporized, but has experienced considerable melt. 
. The current eruption is close to the head of Gígjökull . Gígjökull is a 7.5 kilometer long glacier that empties out of the summit crater area at 1600 meters flowing across the ice cap plateau to 1500 meters then descending steeply in an icefall from the ice cap plateau to the terminus at 200 meters. There are pictures of lahars, Icelandic Met Service, from 4/16/2010 from just east of Gigjokull indicating this glacier is experiencing some substantial melt. The impact of the volcano will result in this glacier not being a good indicator of climate change impact on a glacier going forward, and will exacerbate the rapid recent retreat due to global warming. The Icelandic Met Office conducted a comparison of the runoff from glaciers draining the area around the volcano and from an ice cap in northeast and one in west Iceland indicate that the thick ash layer actually insulated the snow and ice underneath retarding glacier melt. Runoff in Jun-August 2010 a warm, dry period was just below normal in a gaged river draining the icecap near the volcano, and far above normal on ice caps farther from the volcano during summer 2010. Typically it takes a thickness of debris of 2 cm to switch from enhancing to retarding melting. The lahars visible in radar imagery on the 16th are mainly flowing to the south side of the ice cap. Contrast the series of images below from 4/17/2010 and 3/9/2010 from the Icelandic Met Office with the 2005 and 1992 images below. Below are the hydropgraphs from the Icelandic Met Office comparing the 2010 hydrograph of 2010 to those of 2006-2009, 2010 is the black year. 
The climate induced retreat continued up to 2010 as the glacier lost its entire stagnant section adjacent to the lake. And now the lake has been filled in by mud in a matter of days. As of May 2nd the glacier still exists, many would think it had melted away completely, but glacier are tough to melt. The last image is from the Icelandic Institute of Earth Science (Sigrún Hreinsdóttir) 
The image above is from Tómas Jóhannesson, Icelandic Meteorologic Office, and shows that in 1992 there is no indication of stagnation and breakup in the proglacial lake at the teriminus. In addition compare the width of the glacier in that base of the icefall region. In 2005 the large exposed bedrock region is evident, in 1992 it is an active crevassed glacier across this entire region. Given the thickness of the glacier 100-200 meters in this region, this is a very rapid change in thickness. The glacier retreated in the first half of the 20th century but then began an advance that lasted until 1997. From 1997-2005 the glacier has retreated 700 meters according to data reported to the World Glacier Monitoring Service. This is leading to the expansion of the proglacial lake. The current rate of retreat is nearly 100 meters per year. The lower 1.1 kilometers is stagnant and poised for further fairly rapid retreat. The glacier is several hundred meters thick in this region and would melt slowly in place, but can breakup quickly via calving in the proglacial lake at its terminus. How far will this sub glacial trough extend upglacier from the current terminus will be key to understanding how fast this will occur. The view across the lake and a section of the terminus area that was breaking up in 2004 resulting in a retreat of 370 meters from 2003-2005 is seen in the image below from Ó. Ingólfsson
Note that in the image above and below. The lower 1.1 kilometers of the glacier lack crevassing and further has as its upglacier end a large bedrock area that is exposed across half the width of the glacier. this indicates the lack of flow from the icefall region of the glacier into the stagnant terminus zone.
Category: Glacier Observations
Post detailing changes in a glacier
Tulsequah Glacier, British Columbia Jokuhlaups and Retreat
Above is a paired Landsat image from 1984 left and 2013 right indicating the 2500 m retreat during this period of Tulsequah Glacier and formation of a new lake at the terminus. Tulsequah Glacier, British Columbia is a remote glacier draining from the Alaska-Canada boundary mountains of the Juneau Icefield. It is best known for its Jökulhlaups from lakes dammed by Tulsequah Glacier in northwestern British Columbia, Canada (Geertsema, 2000). This Tulsequah Glacier has retreated 1100 m since the Little Ice Age maximum in the 19th century. The continued retreat of the main glacier at a faster rate than its subsidiary glaciers raises the potential for an additional glacier dammed lake to form. The main terminus is disintegrating in a proglacial lake at present. This is not unlike the situation at the Gilkey Glacier just delayed. The images below are from Google earth in 2003 and 2007 and indicate the stagnant nature of the tongue in the lake, and lateral rifting that will be points of instability for a calving disintegration.
As part of the Juneau Icefield Research Program We completed extensive snow pack measurements in the upper reach of the glacier in 1981-1984 and found that snow depths by summers end between 1800-2000 meters averaged 4-6 meters. These observations completed along a transect across the glacier noted in the image below, provide a good example of the different sensitivities of the glacier to global warming. In 1981 a warm winter led to minimal snowpack at lower elevations in the Juneau Region, however, the upper regions of the icefield had above average snowpack. Jabe Blumenthal and I observed snowpack of over 5 meters on the upper Tulsequah Glacier. The areas above 1500 m are not very sensitive to winter temperatures as most as precipitation will fall as snow. In 1982 Juneau had good snowpack and the upper portion of the icefield was gripped by extended cold, the minimum thermometer at Camp 8 registered -44 F. In the images below the ELA for 1984 (right) and 2006 is indicated by a black dotted line, our Camp * a green dot and our accumulation profile is an orange line. In 2006 (left) the ELA is quite high and the accumulation are not large enough for an equilibrium balance. In 1984 the ELA was lower and mass balance was positive. 
Such cold conditions indicate continental dry climate conditions persisting. The result good snowpack low on the glacier and below normal snowpack high on the glacier. From Camp 8 Brian Hakala and I surveyed the upper Tulsequah and found 4 meters of snowpack. In 1984 the highest snowpack of 6 m was noted as Wilson Clayton and I again measured the upper Tulsequah. The glacier still had healthy accumulation. The issue driving the retreat is that the equilibrium line where melting equals accumulation and bare glacier ice is exposed has risen and is now typically at 1400 meters.
When water stored behind, on or under a glacier is released rapidly this outburst is referred to as a jökulhlaup. These outburst floods can pose a serious threat to life and property, but not from the modest floods of the Tulsequah system along this relatively undeveloped watershed. Tulsequah Glacier has a long history of often annual jökulhlaups since the early twentieth century documented by the USGS. The floods resulted after decades of downwasting and retreat of Tulsequah Glacier. In particular a tributary glacier feeding the Tulsdequah retreated and downwasted faster than the main glacier. This valley then was dammed by the main stem of the glacier. There is no surface drainage evident from either Lake No Lake or Tulsequah Lake (labelled TL and NN in image above), indicating all discharge is through a subglacial tunnel.the main stem of the glacier emerging at the terminus and causing modest downstream flooding. 
Each summer as the lake filled with meltwater, its area, level and volume would increase to the extent that the hydrostatic pressure would float the glacier enough to begin flowing, this water then would further melt the ice enlarging its conduit. Most of the release occurs within several days. Hydrologic data are used to reconstruct the times and peak discharges of floods from the glacier-dammed lakes The first jökulhlaups from Tulsequah Lake were the largest. The history of this these jökulhlaups has been declining peak and total discharges as the lake became smaller. Today, Tulsequah Lake is small, and it will disappear completely if Tulsequah Glacier retreats any further. From 1941-1971 Tulsequah Lake discharged annually. Since 1990 a Lake No Lake has been discharging annually. Lake No Lake), has formed and grown in size as Tulsequah Lake has diminished. Lake No Lake developed from a subglacial water body in a tributary valley, 7 km upglacier from Tulsequah Lake. Like Tulsequah Lake, Lake No Lake rapidly grew in area and volume during its youth, and in the 1970s it began to generate its own jökulhlaups. Lake No Lake appears to be following the same evolutionary path as Tulsequah Lake – its volume is now decreasing due to downwasting of Tulsequah Glacier, and its jökulhlaups are beginning to diminish. As Tulsequah Glacier continues to shrink in response to climatic warming, additional glacier-dammed lakes may form, renewing the cycle of outburst flood activity, the tributary where this is most likely is labeled Future New Lake in the final image.
Urumqihe Glacier, China Separation and Retreat
Urumqi No. 1 or Urumqihe No.1 Glacier is in the Tian Shan Range of China. The Tain Shan Glaciological Research Station nearby, has led to this being the most closely observed glacier in China over the last 50 years. The glacier’s elevation ranges from 3740 meters to 4500 meters in 2005 the glacier had an area of 1.8 km2 (WGMS, 2010). In 1993 it separated into a larger east branch and a west branch. Since 1988 glaciological measurements are carried out for both branches separately (WGMS, 2010). The first image below is from Nozuma Takeuchi, Chiba University, Japan The second is from the WGMS submitted by Tobias Bolch in 2006.
The dryness and inhospitable nature of the region is evident. What is also evident is the limited snow extent on the glacier in the upper image of the east branch of the glacier. Both glacier branches are seen below, they joined in the foreground outwash plain region just 13 years before this image was taken. This region is one of the most continental areas of the world, dominated by polar and continental air masses from the Arctic and central Asia from autumn through spring, causing very low temperatures and little precipitation. During the summer months monsoonal air masses account for two thirds of the annual precipitation. This makes the Urumqi a summer accumulation type glacier, unusual outside of the Himalayan region, where peak accumulation on the upper part of the glacier and peak ablation on the lower part of the glacier, take part simultaneously in summer.
The regional increase of average air temperature of 0.7 C from 1987 to 2000 in north-western China has led to significant glacial mass losses, including a loss of 12 meters in glacier thickness on Urumqi Glacier in the last 35 years. The Average annual precipitation measured on the glacier is 600 to 700 mm relatively low for a glacier, an indicator of the continental climate. Most glaciers north of the immediate southern boundary with India and Pakistan, in China belong to the continental type and react slower to climate change than glaciers in warmer and wetter environments. The annual temperature at the equilibrium line is -8 to -9 C, the soils around the glacier feature permafrost. Runoff has been observed in the Urumqi River basin and has increased by 30% from 1983-2006. Comparison of runoff from glacier and non-glacier basins indicate a much larger change, change of 150%-200% in glacierized basins over the last 50 years. This is due to enhanced melting of the glacier, providing runoff that had been in long term frozen storage.
The mass balance is assessed at specific points indicated in the first figure below, 45 locations which is a higher than typical density 25 point per km2. The second figure is the contoured result of these measurements in terms of the snow-ice (measured in water equivalent units) gained or lost across the glacier. In this particular year the area of snow cover for both glacier branches is about 33% this is much less than the 65% needed for equilibrium on this glacier leading to a negative balance in 2006-07 of -650 mm (WGMS,2010). 
The mass loss fits the global pattern and cumulative mean of glaciers reporting to the WGMS. The mass balances losses have continued to increase each decade.
Fairchild Glacier Breakup and Retreat, Elwha River Dam Removal, Washington
The 70 km long Elwha River in Olympic National Park was once of the most productive salmon rivers in the Pacific Northwest, this fall it is getting to for the first time flow from the glaciers to the sea, image of watershed from the restoration project
. At the headwaters of this stream are two named glaciers Carrie and Fairchild, and four unnamed glaciers, which play an important part in the hydrology of the watershed. The glaciers have retreated considerably since the building of the dams, rapidly since 1980. The result is a significant reduction in late summer glacier runoff than when the stream last flowed naturally. The construction of Elwha Dam (1913) and Glines Canyon Dam (1927) devastated the Elwha River’s salmon runs. Dismantling the Elwha and Glines Canyon dams over the next two years will allow the river to flow freely for the first time in nearly 100 years. The river will run from its headwater glaciers to the sea. Dams alter streamflow by withholding water and then releasing the water to generate power during peak demand periods. This leads to unnatural flows, which interrupt natural variations that are critical to the fish and wildlife species. Besides the ongoing dam removal recent climate change is altering the seasonal flow of the Elwha River. The loss of glacier area has and will lead to ongoing significant changes in summer streamflow in the Elwha River. In the Elwha River from 1950-2006 summer streamflow declined by 25%, spring streamflow by 17%, and winter streamflow increased by 6%. Part of this change is due to the loss of glacier extent in the watershed.
Glaciers act as natural reservoirs storing water in a frozen state instead of behind a dam. Glaciers modify streamflow releasing the most runoff during the warmest, driest periods, summer, when all other sources of water are at a minimum. Annual glacier runoff is highest in warm, dry summers and lowest during wet, cool summers. The amount of glacier runoff is the product of surface area and ablation rate. The North Cascade Glacier Climate Project began annual monitoring program of North Cascade glaciers in 1984. This program has also examined the change in glacier volume and extent in the Bailey Range and Anderson Glacier in the Olympic Mountains.
In the Elwha watershed glacier extent has declined from 2.8 km2 in 1980, to 2.6 km2 in 1990, to 2.1 km2 in 2008.
Fairchild Glacier retreated 300 meters from 1950-1994, topographic map versus aerial photograph, green versus red line. From 1994-2009 another 240 m of retreat occurred as indicated by the orange line. In addition the Fairchild Glacier has separated into three sections by 2009. 
The greatest concern is the emergence of bedrock outcrops in the midst of the glacier since 1994, burgundy arrows in the 2009 image. This is a key symptom of a glacier that will not survive (Pelto, 2010). This is leading to the breakup of the glacier into smaller easily melted segments. This is a process that we have observed lead to the demise of glaciers like the Hinman Glacier. The emergence also indicates the thin nature of the glacier. The view of the glacier from 2005 illustrates the small area of the glacier that is retaining snowpack, this is not a good sign for survival of this glacier.At the end of the summer melt season a glacier needs to be at least 50% snowcovered, to survive it must have a consistent significant area of snowpack. In 2005 in this August picture only 20% of the glacier is snowcovered and by summers end it was 5%. 
The consequent glacier runoff has declined by 750,000-850,000 ft3/day in the summer since 1980. The resultant annual hydrograph for the Elwha River is not the same as it was before dam construction. In particular late summer and fall salmon runs will experience less runoff due in part to declining glacier runoff. Streamflow in the Elwha River has declined 25% during July-Sept. for the 1950-2006 period. The mean summer flow from 1950-1991 was 1034 cfs. From 1992-2009 only two summers had mean streamflow above 1034 cfs. The decline in glacier size is not the principal cause of the summer streamflow decline, but it further reduces the summer low flows. Updated 12/14/2011
Waputik Icefield Outlet Glacier retreat, Alberta Canada
The Waputik Icefield, near the Icefields Parkway, north of Banff, Alberta straddles the continental divide. The Waputik outlet “Liiliput” Glacier is a 3 kilometer long outlet draining east into Hector Lake and the Bow River. This glacier drains the north side of Lilliput Mountain, and is just southeast of Balfour Glacier, which it merged with in the late 19th century. That is why the glacier lacks a proper name, it was part of the Balfour Glacier when named. The Lilliput Glacier has retreated 2.3 km from its maximum. The Balfour Glacier with which it was joined retreated at a rate of 10 meters per year at the end of the 19th century and 40 meters per year up to 1945, by 1945 the glaciers had separated (Ommaney, 2000). From 1945 to 1970 limited retreat occurred on either Lilliput or Balfour Glacier.
This Lilliput Glacier is now continuing to retreat, 320 meters since the 1970 picture of the glacier was taken. In 1970 the glacier still has a single terminus in the valley and ended a short distance above a steep bedrock slope. 
By 1994 the glacier has developed two termini and has retreated 200 m from the 1970 position. The 2002 terminus in this Google Earth image has retreated an additional 100-200 meters depending on location along the front. A closeup of the terminus area indicates limited crevassing, indicating limited movement and continued retreat. The supraglacial stream (winding stream channel on glacier surface) that is visible has downcut a considerable channel, this too indicates limited movement. An active glacier terminus would closeup such a channel seasonally as movement continued and meltwater flow ceased. 
The glacier in 2002 still has an accumulation zone at the head of the glacier. For a glacier like this to be in equilibrium it needs at least 50% of its area to be snowcovered at the end of the summer, this percentage is the accumulation area ratio. In the image below the lines are annual accumulation horizons exposed in the glacier ice. This indicates a region of the glacier that is consistently exposed to ablation today. Only 40% of the glacier is snowcovered above this point. This indicates how little of the glacier is a consistent accumulation zone today. Without a consistent accumulation zone the glacier cannot survive.
Brady Glacier, Alaska begins a substantial retreat
Brady Glacier is a large glacier at the south end of the Glacier Bay region, Alaska. When first seen by George Vancouver it was a calving tidewater glacier in 1794 filling Taylor Bay with ice. Brady Glacier ceased calving and advanced approximately 8 km during the 19th century (Klotz, 1899). As Bengston (1962) notes, the advance is likely another example of an advance following a change from tidal to non-tidal status rather than that of a more positive mass balance. Bengston (1962) further notes that the massive outwash plain at the terminus is primarily responsible for Brady glacier maintaining itself well other glaciers in the Glacier Bay region retreat. The ELA on this glacier is 800 m, the line above which snow persists even at the end of the average summer, this is one of the lowest in Alaska. The main terminus was still advancing in the 1960’s and 1970’s and has managed a 250-300 meter advance since the USGS map of the 1950’s. The main terminus is not advancing any longer and has begun to retreat, the retreat to date is less than 200 meters. The image below is the 1950’s map of the glacier. 
Brady Glacier is a complex glacier with many subsidiary termini. Echelmeyer, Arendt, Larsen and Harrison from the University of Alaska noted a thinning rate in the mid 1900’s of about 1 meter per year on the Brady Glacier complex. A comparison of 1950’s USGS maps and 2004-2006 satellite imagery indicate all six main subsidiary termini are retreating. The retreat ranges from 200 m in Abyss Lake, 200 m in Trick Lake to 1200 meters in North Deception Lake. The image below is the 2006 satellite image. Compare to the map, Deception has increased in size several fold. North Trick and South Trick Lake are now joined, Trick Lake. 
Of further interest is the stream draining Trick Lake that sneaks down the west margin of the glacier. This has enabled the water level in the glacier dammed Trick Lake to decline. Note the brown grey “Bath Ring” so to speak above the lake level. The outlet has also been marked in the image below. Pelto (1987) noted that the percentage of the glacier in the accumulation zone was right at the threshold for equilibrium. Subsequent warming of the climate in southeast Alaska and reduced glacier mass balance in the region has initiated this retreat.
These termini are all closer to the equilibrium and would respond first to changes in mass balance due to recent warming and consequent measured thinning. This entire line of reasoning must be explored. The glacier is thinning substantially and would appear to be poised for a substantial retreat of the main termini, not just the subsidiary termini.
References not linked:
Bengston, K. recent behavior of Brady Glacier, Glacier Bay National Monument, Alaska. IAHS, 58, 59-77.
Klotz O. 1899: Notes on glaciers of southeast Alaska and adjoining territories. Journal of Geography, 14, 523-534.
Pelto, M. 1987. Mass balance of southeast Alaska and northwest British Columbia glaciers from 1976 to 1984: Methods and Results”. Annals of Glaciology 9: 189–193.
Rotmoosferner Retreat and Dynamic Change
There are currently 51 glaciers in the Ötztal Nature Park. Right now, glaciers cover 27% of the total area of the Ötztal Nature Park. All have been retreating, from 1987-2006. Detailed mapping of these glaciers and Rotmoosferner by Abermann and others (2009), University of Innsbruck provide interesting results. Ötztal glaciers lost 8 % of their total area. One of the glaciers that has a long record of observation is Rotmoosferner. This glacier has retreated 2.1 km since the Little Ice Age and 600 meters since 1969, 15 meters per year. A detailed map of Rotmoosferner from Abermann and others (2009) University of Innsbruck indicates that in 1975 it was joined to the Wasserfallferner, but in 2005 it separated. 
In the image above the Rotmoosferner is to the lower left and the Wasserfallferner above and to the right. Compare this image to one taken four years later at the end of the post. In the last decade new rock outcrops have emerged in the middle of the Rotmoosferner. These outcrops are noted in the google earth image below. The annotated image also indicates the former zone of connection to the Wasserfallferner. 
A map of the outline of the glaciers clearly identifies the new outcrops and the separation of the glaciers. The map is based on satellite imagery and older aerial photographic based maps by Abermann and others (2009) from 1969, 1997 and 2006. The retreat from 1969-1997 occurred across a relatively flat foreland. The current retreat is up a steeper slope, since 2001 retreat has averaged 18 m per year. The appearance of the rock outcrops in the mid-section of the glacier as the map shows, indicates little contribution to the tongue of the glacier, and that retreat of this lower section will continue to be rapid. The glacier still does appear to have an accumulation zone most years and is thus not forecast to disappear with current climate. 
The picture below is from September of 2008 from Jakob Abermann, Institute of Meteorology and Geophysics, University of Innsbruck. Note the change versus the first picture from four years earlier. The exposed rock area has expanded amazingly and is nearly cutting off the lower tongue.
Colonial Glacier Retreat and Hydropower
Colonial Glacier is on the southwest side of Colonial Peak in the Skagit River Watershed, North Cascades of Washington. The North Cascade Glacier Climate Project has made six visits to this glacier over the last 25 years. Meltwater from this glacier enters Diablo Lake above Diablo Dam and then flows through Gorge Lake and Gorge Dam. These two Seattle City Light hydropower projects yield 360 MW of power. As this glacier shrinks the amount of runoff it provides during the summer for hydropower is reduced. In 1979 the glacier was clearly thinning, having a concave shape in the lower cirque, but still filled its cirque, there is no evidence of a lake in this image from Austin Post (USGS). The glacier had retreated 80 meters since 1955. In 1985 my first visit to the glacier there was no lake at the terminus. In 1991 the lake had begun to form, second image, but was less than 30 m across. The upper glacier was a smooth expanse of snow. 
By 1996 the lake was evident, and was 75 meters long. In 2001 the lake had expanded to a length of 125 meters. By 2006 the lake was 215 m in length, and had some thin icebergs broken off from the glacier front. Runoff to the Skagit River is impacted directly by the climate change and the resultant retreat of the glaciers. Three notable changes in North Cascade streamflow have occurred.
1) Alpine runoff throughout the North Cascades is increasing in the winter (Nov.-Mar.), as more frequent rain on snow events enhance melting and reduce snow storage Streamflow has risen 18% in Newhalem Creek and 19% in Thunder Creek despite only a slight decrease, 1% in winter precipitation at Diablo Dam, within 5 km of both basins. These basins are on either side of Colonial Glacier.
2)Spring runoff (April-June) has increased in both basins by 5-10% due to earlier alpine snowpack melting.
3)Summer runoff has decreased markedly, 27%, in the non-glacier Newhalem basin with the earlier melt of reduced winter snowpack. In Thunder basin runoff has in contrast increased negligibly, 4%. The difference is accounted for in part by enhanced glacier melting. The observed net loss of -0.52 meters per year in glacier mass spread over the melt season is equivalent to 2.45 cubic meters per second in Thunder Basin, 10% of the mean summer streamflow. This trend of enhanced summer streamflow by reduction in glacier volume will not continue as the extent of glaciers continues to decline.
The lower portion of Colonial Glacier is not moving. GPS readings on both rockpiles on the lower glacier indicated no movement from 1996-2006. In the picture above the lake is still small in 1996, lower right corner and the lower rock pile distant from the terminus. The first two images below are from 2006, the lower rock pile is near the terminus and the last image is 2007 the lake has expanded back to the lower rockpile. Additional rock outcrops have appeared in the midst of the upper glacier that were not present in 1991, indicating this glacier does not have a persistent accumulation zone and will not survive current climate.
Gangotri Glacier Retreat Continues 2013 and Hydropower
In India the Gangotri Glacier is the largest glacier at the headwaters of the Bhagirathi River. The false-color image below provided by NASA shows the retreat of Gangotri Glacier, situated in the Uttarkashi District of Garhwal Himalaya. It is one of the larger glaciers in the Himalaya, and like all of the nearby Himalayan glaciers is retreating significantly. 
The Bharigrathi River has the Tehri Dam, a 2400 mw hydropower facility. With an area of 286 square kilometers Gangotri Glacier (Singh and others, 2006) provides up to 190 cubic meters per second of runoff for this river. Gangotri Glacier provides hydropower as it passes three hydropower plants generating 1430 MW, including the 1000 MW Tehri Dam and reservoir and maneri Bhali I and II, see map below. The Tehri also provides flood control, such as this past week of June 17, 2013. The Tehri Reservoir level rose 25 m within 48 hours which is a storage of approximately 1.3 billion cubic meters. Below is a view of the Tehri Reservoir, images of the dam and its operations are here. 
Map from the Southeast Asian Network on Dams, Rivers and People
Gangotri Glacier retreated 26.5 meters per year form 1935-1971. From 1968-2006 the glacier retreated 800 meters, close to 20 meters per year (Bhambri et al, 2012). Srivastava et al (2013) indicate the retreat rate of 21 m/ year from 2004-2010. The glacier continues to thin and tributary inflow decline, while the thick heavily insulated by debris terminus retreat is slow. Srivastava (2012) published a report with numerous terminus pictures though they do not have a common reference point beginning on page 90. Where the river exits the glacier is referred to as Gomukh.
Here we compare both Landsat and Google Earth images during the 2000-2013 period. First the 2000 and 2013 Landsat images. A 2000 and 2013 landsat image pinpoint the terminus change, the yellow and red arrows converge on the 2000 location of Gomukh. The blue arrow indicates the mouth of a side valley from the east that is at the terminus in 2013 and actively cutting the face, which is not the case in 2000. The orange dots indicate the course of this stream. A 2006 Cartosat image from Bhambri et al (2012) can be compared to the 2010 and 2013 Google Earth images. In Google Earth the 2010 image gives a clear view of Gomukh which can be compared to the 2006 Cartosat image from Bhambri et al (2012). In 2000 and even 2006 this was not the case. A 2013 Google earth also indicates this point,with the glacier having retreated to the side valley from the east. The retreat from the location of Gomukh in 2000 to 2013 is 240-270 m, approximately 20 m per year as noted by Srivastava et al (2013) for a shorter interval.
2000 Landsat image
2013 Landsat image
.
2006 Cartosat image
2010 Google Earth image
2013 Google Earth image
2013 Google Earth image
This glaciers remains over 30 km long, and is not in danger of disappearing anytime soon. The lower section of the glacier is heavily debris covered, which slows melting. The debris cover prevents black carbon-soot from enhancing melt over most of the ablation zone. The upper reaches of the glacier extends above 6000 meters and remains snow covered even during the summer melt season June-August, as this is also a main accumulation season due to the summer monsoon. This is different from other alpine regions, where the melt season is also the dry season, here it coincides with the wet season and the accumulation season on the upper glacier. Compare the differences in hydrographs from Thayyen and Gergen (2009) Figure 3 and 4. The new snowcover on the upper glacier also limits the impact of black carbon or soot on ablation. The glacier is fed from avalanches off of the even larger area of mountains above 6000 meters adjacent to it. This is one of many glacier in the Himalaya that is being tapped for hydropower. The retreat is slower than that of nearby Malana Glacier and Samudra Tupa Glacier but similar to Durung Drung Glacier. 
Forni Glacier, Italy Retreat
Forni Glacier is the largest valley glacier in Italy. It is currently 5 km long and has retreated 2.5 kilometers since its Little Ice Age Maximum. It is in the Cevedale Group, Alps and part of the Parco Nazionale dello Stelvio. In this image the Little Ice Age terminal moraine is the prominent sharp debris ridge in the foreground, twenty years ago the glacier descended beyond the bottom of the image. The Italian Glaciologic Commission has observed and reported its annual terminus change over the last 30 years to the World Glacier Monitoring Service. The glacier began a sustained retreat in 1988, after advancing a small distance in the 1970-1987 period. As reported by the IGC to the WGMS from 1990-1995 Forni Glacier retreated 290 m, between 1995 and 2000 130 m, and from 2000-2005 115 m. Using IKONOS (Bellingeri and Zini, 2006
stereoscopic high resolution imagery linear retreat of the glaciers tongue was established as 520 meters for Forni Glacier in the 1981-2003 period. The glacier was found to have lost an average of 15 m in thickness in this period, 60 m near the terminus. The glacier as seen below above the key icefalls has a substantial consistent accumulation zone. It is the terminus tongue below the icefall that is at risk with current climate. 
A close up view of the terminus illustrates the region that has been deglaciated in the last 20 years, there is virtually no green vegetation evident in this region. The lower section of the glacier is rapidly downwasting still. 
Boulder Glacier Retreat, Mount Baker
Boulder Glacier flows down the west side of Mount Baker a strato volcano in the North Cascades of Washington. This steep glacier responds quickly to climate change and after retreating more than 2 kilometers from its Little Ice Age Maximum, it began to advance in the 1950’s as observed by William Long. The glacier advance had ceased by 1979. From 1988-2008 we (NCGCP) have visited this glacier at least every five years recording its changes. In 1988 the glacier had retreated only 25 meters from its furthest advance of the 1950-1979 period. By 1993 the glacier had retreated 100 m from this position. At this time the lower 500 meters of the glacier was clearly stagnant. By 2003 the glacier had retreated an additional 300 m. In 2008 the glacier had retreated 490 meters from its 1980 advance position, a rate of 16 meters per year. The glacier as seen in 2008 despite the steep slope has few crevasses in the debris covered lower 400 meters of the glacier. This indicates this section of the glacier is stagnant and will continue to melt away. The transition to active ice in at the base of the icefall on the right-north side of the glacier. Below is the glacier in 1993 note the darkened cliff at adjacent to and right of the terminus. The picture below that is from 1998 again note cliff, than in 2003 from the same location as the 1993. Than an image from 2008 of the terminus from further upvalley, as it is not clearly in view from the previous location. And a picture from Asahel Curtis taken in 1908. This glacier after 25 years of retreat is still not approaching equilibrium and will continue to retreat. This is a reflection of continued negative mass balance as measured on the adjacent Easton Glacier. It does respond fast to climate change, and the climate has not been good for this glacier. The glacier does have a consistent accumulation zone and can survive current climate.
Picture from August, 1993 of the terminus of Boulder Glacier
Picture from August 1998 of the terminus of Boulder Glacier
Picture from August 2003 of the terminus of Boulder Glacier.
Boulder Glacier in August 2008.
Boulder Glacier in 1908 viewed across the glacier at the present terminus location during a Mountaineers trip taken by Asahel Curtis. A satellite image from 2009 (green=2009, brown=2006, purple=1993 yellow=1984), shows additional retreat now at 515 meters from 1984 to 2009, 20 meters per year. An examination of the same view of the terminus in 1993 and 2009 indicates the extent of the retreat and the reduction in crevassing below the icefall. (
For 30 years the North Cascade Glacier Climate Project has focused on observing the response of glaciers to climate change.
Rembesdalsskaka, Norway Current Retreat
The Hardangerjøkulen Ice Cap is situated in southern Norway,150 km from the western coast. This elliptical shaped ice cap covers 73 square kilometers and ranges in altitude from 1020 to 1865 meters. It rises above the community of Finse offering access to snow year around. Norway has the most comprehensive glacier monitoring program in the world, mainly due to the heavy reliance on hydropower, for which glacier runoff is a key input. The Rembesdalsskaka drains west from the ice cap, the left side feeding the Rembesdalsvatnet Reservoir. 
The research is led by the The Norwegian Water Resources and Energy Directorate (NVE). Statkraft runs the Sima power station that is fed from Rembesdalsvatnet Reservoir and the larger Sysenvatn fed by the southern glaciers of Hardanger. This system produces 620 Mw of hydropower. The largest glacier draining the western side of the ice cap is the Rembesdalsskaka with an area of 17 square kilometers. Since the LIA maximum Rembesdalsskaka has retreated almost two kilometres, The ice cap decreased in volume from the Little ice Age until 1917, followed by an increase in ice cap volume and glacial advance until 1928, . After this a period with high negative mass balances cause a rapid retreat of Hardangerjøkulen until 1950. Retreat continued until 1961, but the rate declined. From 1961 to 1995 mass balances increased, with the highest balances in the late 1980’s and early 1990’s. This resulted in an advance of Rembesdalsskaka. Since the early 1990’s mass balance has been negative, with exceptionally negative years in. This has led to the retreat of the Rembesdalsskaka each year from 2000-2009 a total of 307 meters. 
The retreat is measured each year from a benchmark painted on rock beyond the terminus, reported to the NVE and then to the World Glacier Monitoring Service. In 2009 the NVE reported 19 glaciers retreated, 3 were stationary and one advanced.
From a Glaciers Perspective 
