Slender Glacier, Brooks Range, Alaska: Rapid Retreat 1992-2014

Slender Glacier is not an official name, but a well suited name to this glacier in the Romanzof Mountains of the Brooks Range of Northern Alaska. It is adjacent to the Okpilak Glacier and drains into the Okpilak River, which is host to arctic grayling. Here we examine Landsat imagery from 1992-2014 to identify changes. U-Alaska-Fairbanks has an ongoing program in the nearby Jarvis Creek Watershed examining in part how will the anticipated future increase in glacier wastage and permafrost degradation affect lowland hydrology. Matt Nolan (U-AK-Fairbanks) reports on changes of nearby McCall and Okpilak Glacier. These glacier have suffered increased mass loss since 1990 as a result of an increase in the equilibrium line altitude that has reduced accumulation area and is indicative of increased ablation (Delcourt al , 2008)

USGS 1951 map

In 1992 the glacier extended downvalley to the red arrow at 1530 m. The glacier also received contribution from a tributary glacier at Point A. By 2002 the glacier had receded a short distance from the red arrow and still received input from the tributary glacier at Point A. By 2013 the glacier had receded to the yellow arrow 1100 meters from the 1992 terminus position, and now terminates at an altitude of 1675 m. The tributary glacier is no longer connected to Slender Glacier at Point A. The percent of snowcover is better than on Okpilak Glacier immediately to the west, or East Okpilak Glacier to the southeast. The first tributary entering the glacier on the east side is also disconnecting from Slender Glacier. In 2014 the Landsat image is after a light snowfall that has endured only on the glacier ice, helping outline the glaciers. The continued decline in retained snowfall and contributed snowfall from tribuatry glaciers will lead to an even more slender glacier.

1992 Landsat Image

2002 Landsat Image

2013 Landsat Image

2014 Landsat Image

Google Earth images from 2006 and 2012 indicate a rapid retreat of the thin main terminus, and the loss of contact with the tributary glacier at Point A. The retreat is similar to that of Fork Glacier and Romanzof Glacier in the same region. The retained snowcover in 2012 is minimal on Slender Glacier and its tributaries. Tributary A lost almost all snowcover in 2012 and 2013 suggesting a lack of a consistent accumulation zone, which a glacier cannot survive without (Pelto, 2010)

2006 Google Earth Image and 2012 Google Earth image

Kokanee Glacier Spring 2015 Assessment, British Columbia

On June 15, 2015May 3, 2024 By mspeltoIn Canada glacier retreat, glacier climate change, Glacier Observations, glaciers salmon

Guest Post by Ben Pelto

Kokanee Glacier is located in the Selkirk Mountains of southeastern B.C., 30 km northeast of Nelson in Kokanee Glacier Provincial Park. Kokanee Glacier drains into the Joker Lakes, the uppermost of which are turquoise due to glacier flour input. Joker Creek carries the water downstream, eventually feeding into the Kootenay Lake and the Kootenay River, which flows to meet the Columbia River in Castlegar, B.C. In the last few years a decline in the number of fish inventoried in feeder streams to the lake caused cancellation of the Fishing Derby in 2015. The Meadow Creek spawning channel usually supports 500,000 to one million kokanee spawners, declined to less than 200,000 annually. In fall 2014, their numbers were down to 60,000. A drop of snow melt from this glacier also would pass through 16 hydroelectric facilities before reaching the ocean.

Kokanee Glacier looking west towards camp. April 20th, 2015 Photo: Ben Pelto

A research team from the University of Northern British Columbia and the University of Calgary began visiting the glacier each spring and fall beginning in 2013. Fall access to the glacier is via the Gibson Lake trailhead, which is a 7.5 km hike to Kaslo Lake and the new Kokanee Glacier Cabin (Slocan Chief cabin is only 1 km farther up the trail, but is no longer in use as a backcountry cabin). Spring access is via helicopter under a research permit. The Kokanee Glacier is north-facing and extends from 2800 meters at the summit of Kokanee Peak, to 2230 m where it terminates in an unnamed lake. This lake is a recent addition to the Joker Lakes, due to glacier retreat in the past two decades. The Kokanee Glacier covers about 1.7 km2.

Contour map of the Kokanee Glacier, with the uppermost Joker Lake. Approximate current terminus position purple-dashed line. Oval indicates new proglacial lake.

Our spring visit to the glacier documented snowpack deposited during an anomalously warm winter, as shown in the image below from the North American Freezing Level Tracker. The tracker is run by Idaho State University and estimates freezing levels based on the NCEP/NCAR Global Reanalysis, which is determined every six hours. Freezing level is the elevation where air temperature is 0°C at a given time. Freezing levels are important to mountain hydrology and determine whether precipitation falls as rain or snow, the elevation of the rain/snow line, whether the ground is frozen when snow falls in the autumn, the efficiency of snowpack accumulation through the winter (melt events, rain on snow), the internal temperature of the snowpack (which drives melt and metamorphosis of the snowpack), and the length of snow free season at a given elevation. What is immediately apparent is that freezing levels were elevated throughout the accumulation season, which generally begins in late September. Freezing levels were highest relative to the median in the key winter months of January through March. Local skiers and ski guides complained of rain during many storms, which reached to or near the mountain tops and left poor skiing conditions.
Estimated freezing levels for Kokanee Glacier for July 2014 to June 2015 North American Freezing Level Tracker

The Redfish Creek snow pillow is the nearest snow pillow site (see below), and is located 7 km southeast of the glacier at 2086 m. The Kokanee Glacier extends from around 2230 m to 2800 m so the snow pillow site may not accurately represent the amount and type of precipitation on the glacier. Regardless, this winter featured a fairly average snowpack, generally hovering above the mean SWE (snow water equivalent), which is calculated from 2001, when the gauge was installed, to present. A precipitous drop in SWE marked an early and strong start to the melt season, with maximum snowpack coinciding with our visit (April 19-21, 2015), roughly two weeks ahead of the usual SWE maximum date (in the first week of May) as seen by the purple line.

Redfish Creek snow pillow site of the B.C. River Forecast Center for 2014-2015.

The primary goal of our trip was to assess winter accumulation. Our measurements consisted of probing snow depth and digging snow pits. We took 80 probe measurements at 20 locations, and dug two snow pits, one at 2475 m and one at 2675 m. While snow depth was lowest near the terminus at 3 to 3.5 m, there was no correlation between elevation and accumulation from 2300 m and above, which accounts for a majority of the glacier area. Above 2300 m, snow depth ranged from 4.3 to 6.3 m with an average of 4.8 m.

Probing snow depth on the Kokanee Glacier, April 20th, 2015. Photo: Alison Criscitiello.

Our measurements revealed that this year’s snow pack was a dense one, likely due to mid-winter melt events, rain-on-snow events, and increased temperature during snow events. Given that snowpack was low across B.C. in the winter of 2014-2015, it would have been reasonable to assume that the glacier fared poorly. However, the winter balance was precisely halfway between the healthy winter balance of 2013 and the weak winter balance of 2014. Our data indicate that freezing levels played a large role in this year’s snowpack for the Kokanee Glacier given that the surrounding region is below 50% of normal snowpack, yet the glacier is much closer to normal as it was still above even the high 2015 winter freezing levels. Given our limited sample size, with this being the third measured winter accumulation, it is beyond the scope our data to assess how close to or far from normal this winter’s snowpack was for the Kokanee Glacier.

Standing on the glacier looking down valley, we observed that bare ground began around 1800 m where there should have still been a couple meters of snow. This highlighted the stark contrast between high and low elevations. Clearly, rain dominated below 1800 m this winter. This winter may be a potential model for the immediate future climate, where increased winter temperatures lead to a higher snowline, lower snowpack at lower elevations, and near average snowpack at higher elevations. Given the early start to fire season in B.C. and the Yukon, similar winters will come at a high cost for fire fighting, forest productivity, and water resources.

View looking west from Kokanee Glacier April 19, 2015. Approximate snow line yellow dashed line ~1800 m. Red J indicates location of uppermost Joker Lake. Red T is just beyond the terminus, which cannot be seen due to the slope. Photo: Ben Pelto

4.5 m deep snow pit at 2675 m on the Kokanee Glacier, April 20th, 2015. Photo: Alison Criscitiello.

The B.C. River Forecast Center releases a monthly snow report, and stated that temperatures in the Kootenay Region, where the Kokanee Glacier is located, were 3 to 5°C above average. The image below shows that by May 1, snowpack was 67% of average. The June 1st map has all but three sub-regions of B.C. exhibiting less than 50% of normal snowpack, with the West Kootenay region at 30% of normal. The result will be less snowpack across southern BC this summer. At the end of August last year there was considerable bare ice and firn exposed on Kokanee Glacier, this year we anticipate even more upon our return at the end of the melt season. Of course the snow report is critical for hydropower in BC. For the Kokanee Glacier, meltwater goes through a series of hydropower dams on the Kootenay River.

May 1, 2015 Snow Report Map, B.C. River Forecast Center. Kokanee Glacier located by Nelson in SE B.C.

Kokanee Glacier, Aug. 27th 2014. the darker areas are either firn that has survived more than one summer or bare glacier ice.

Kootenay River Hydropower.

Salmon Challenges From Glaciers to the Salish Sea

On June 8, 2015May 3, 2024 By mspeltoIn Canada glacier retreat, glacier climate change, Glacier Observations, glaciers salmon1 Comment

The Salish Sea includes Puget Sound, the Strait of Georgia, and the Strait of Juan de Fuca of Washington and British Columbia. The Salish Sea supports all seven species of Pacific salmon, chinook, chum, coho, cutthroat, pink, sockeye and steelhead. Population declines have prompted initiation of the Salish Sea Marine Survival Project. This project reports that: chinook, coho, and steelhead have experienced tenfold declines in survival during the marine phase of their lifecycle, with total abundance remaining well below levels of 30 years ago. The conditions in the Salish Sea have changed and salmon survival has been declining, Zimmerman et al (2015) observed the primary pattern within the Salish Sea is declining smolt survival from 1977-2010. Of course the salmon begin and end their life cycle in the streams, many glacier fed, and these too have experienced changes that are not favorable for salmon. The Salish Sea is fed by numerous glacier fed streams, all of which have experienced substantial retreat in the last 30 years, with many already experiencing significant summer declines in overall and glacier runoff (Stahl and Moore, 2006; Pelto, 2008). The largest input river is the Fraser River (FR), Padilla et al (2014) note an increasing variability in summer flow, and with a warming climate greater variability in annual streamflow, and hence in hydrological extremes is anticipated, which is not favorable to salmon. This post provides selected specific examples of observed changes on glaciers in the Salish Sea watershed.

Modified Map from Environment Canada

Salmon Changes from the Salish Sea Marine Survival Project

The loss of the north branch of the Whitechuck Glacier

The Whitechuck Glacier supplies flow to the headwaters of the Whitechuck River. Its white expanse has graced these headwaters for thousands of years. The Whitechuck Glacier retreated slowly from its advanced Little Ice Age position until 1930, while rapidly thinning. Thus, prepared it began a rapid retreat in 1930. This rapid retreat culminated in the total disappearance of the north branch of the glacier in 2001, our third visit to the glacier. No more does this glacier dominate the headwaters, and its demise has and will continue to alter the hydrology of the Whitechuck River headwaters.The amount of runoff entering the Whitechuck River has declined substantially in the summer. For thousands of years each square meter of glacier has contributed 3 cubic meters of runoff from July I-October 1. With the loss of glacier ice, this contribution should drop by 65-80% based on observations at two other sites where glaciers have disappeared (Pelto, 1993 & 2008). The change since 1950 in glacier area has reduced summer glacier runoff by 5.7 million cubic meters annually. This represents a loss of between 0.55 to 0.65 cubic meters/second for the Whitechuck River during the July-September period. The water will also be less sediment laden and warmer. The impact will be less water for the fall salmon runs, and less food in amount and processing for stream invertebrates on which salmon feed downstream in the Sauk and Skagit Rivers. Milk Lake Glacier also fed this watershed before disappearing in the 1990’s.

Milk Lake Glacier on USGS map from 1979 and in 2009.

Nooksack River: For 31 years we have completed measurements of ablation, glacier area change and runoff in this basin, all are losing mass and retreating (Pelto and Brown, 2012). During stressful warm weather events in the last five years we have measured ablation on and runoff from glaciers in the basin. In addition the USGS gages record discharge and stream temperature in the South Fork, Middle Fork and North Fork Nooksack. During these events runoff measurements below Sholes Glacier and ablation measurements on Sholes Glacier indicate daily ablation ranging from 0.05-0.06 meters per day, which for the North Fork currently yields 9.5-11 cubic meters/second. This is 40-50% of the August mean discharge of 24 cubic meters/second, despite glaciers only covering 6% of the watershed. In the unglaciated South Fork all 12 warm weather events generated a rise in stream temperature of at least 2 C, only 2 event in the North Fork generated this rise. Discharge rose at leasts 15% in 10 of the 12 events in the North Fork and none of the events in the South Fork. As the glaciers continue to retreat the North Fork will trend first toward the more limited impact of the Middle Fork and then the highly sensitive South Fork where warm weather leads to declining streamflow and warming temperatures. Our ongoing measurements of daily runoff and daily streamflow below Sholes Glacier allow determination of the contribution of glaciers to the North Fork Nooksack, which peaked in 2014 at 80% of total streamflow. Glacier runoff surpassed 40% of the total streamflow on 26 days after Aug. 1 in 2014. The Nooksack Salmon Enhancement Association has completed numerous salmon restoration efforts, but climate is one challenge that cannot be restored locally.

Deming Glacier Retreat 1984-2011-headwaters Middle Fork Nooksack River

Response of watersheds to warm weather events.

Skykomish RiverThe reduction of the glacial melt component augmenting summer low flows is already resulting in more low-flow days in the North Cascade region. In the Skykomish River watershed from 1958-2009 glacier area declined from 3.8 km2 to 2.1 km2, a 45% decline (Pelto, 2011). A key threshold of in-stream flow levels considered insufficient to maintain short term survival of fish stocks is below 10% of the mean annual flow (Tennant, 1976). For the Skykomish River 10% of mean annual flow is 14 cubic meter/second. In the Skykomish River from 1950-2013 there have been 230 melt season days with discharge below 14 cubic meter/second. Of these 228, or 99% of the low flow days, have occurred since 1985. The loss of 30-40% of the glacier runoff is a key reason for the onset of more critical low flow days. Of more concern for aquatic life is the occurrence of extended periods of low flow (Tennant, 1976). From 1929-2009 in the Skykomish River basin there have been eight years where streamflow dropped below 14 cubic meter/second. for 10 consecutive days during the melt season, 1986, 1987, 1992, 1998, 2003, 2005, 2006 and 2007. It is likely that 2015 will join this list

Lynch Glacier, Skykomish Basin in 1978 (Bill Prater, Photograph) when Pea Soup Lake was filled with ice and in 2007 with the glacier no longer reaching the lake.

Fraser River-Southern BC: Koch et al,(2009) observed a widespread retreat and glacier area loss in Garibaldi Provincial Park just to the west, with 20% area loss from 1988-2005. Bolch et al (2010) noted that from 1985-2005 that glaciers in the southern Coast of British Columbia lost 10% of their area, 0.6% per year and that the rate was increasing. By 2015 this area loss is certainly greater than 15%. For a longer time span Tennant et al (2012) noted that from 1919-2006 the glaciers in the central and southern Canadian Rocky Mountains lost 40% of their area. Of the 523 glaciers they observed 17 disappeared and 124 separated. Many of these do not drain into the Salish Sea, but does give a sense that the overall change is larger than 20%.

The change in glacier area is key because observed melt rates increases have been less than 20%. Hence, as glacier area declines at a greater rate than glacier melt rate, glacier runoff declines. The Helm Glacier below exemplifies the change from a shrinking area of ice available for summer melt, since 1928 the glacier has lost 78% of its area. Helm Glacier drains into the Cheakamus River, which supplies Daisy lake Reservoir and the BCHydro 157 MW Cheakamus Power Plant. The Cheakamus River has the Dave Marshall Salmon Reserve with over 14 kilometres of winding, re-enhanced salmon spawning river channels off the Cheakamus.

Helm Glacier, Garibaldi Provincial Park, BC 1928 extent on 2009 Google Earth image

Snowcap Creek Glacier has retreated 900 m since 1992 with a new lake forming at its terminus. This glacier drains into Harrison Lake. Harrison Lake is considered a location where salmon populations have remained stronger and features five species of salmon – sockeye, chinook, pink, coho, and chum that pass through the lake in the summer enroute to spawning grounds.

Snowcap Creek Glacier shares a divide with Stave Glacier at the headwaters of Stave Lake which is the part of the 205 MW Stave Lake-Hayward Reservoir-Ruskin Dam Hydropower facility. The dams do not have fish passages cutting off salmon from most of the watershed. There are kokanee salmon a landlocked version of the sockeye salmon.This glacier has retreated at a rate of 100 meters per year from 1996 to 2012. This is the fastest rate of retreat since 1900 (Koch et al, 2009).

Red and Yellow Arrow indicate new lakes formed in the last six years by retreat of Snowcap Creek Glacier.

Stave Glacier Retreat Koch et al (2009) documented retreat from 1952-1996.

Overall salmon are being faced with increasing climate stress in rivers on top of long term habitat alteration at the beginning and end of their life cycle, then mature in the changing and challenging conditions of the Salish Sea. Our Nooksack Indian Tribe partners Oliver Grah and Jezra Beaulieu discuss glacier runoff measurement, runoff changes and salmon in an interview completed during work at the runoff gage below Heliotrope Glacier on Mount Baker.

Big Bend Glacier, British Columbia Transitions to Alpine lake

On June 4, 2015May 3, 2024 By mspeltoIn Canada glacier retreat, climate change glacier retreat, glacier climate change, Glacier Observations

“Big Bend” Glacier is an unnamed glacier west of Big Bend Peak north of Harrison Lake in Southwest British Columbia. In 1985 the glacier was 2.6 km long filling a low valley with a surface elevation of 1600-1800 m elevation, the topographic map indicates this basic size. Here we utilize Landsat imagery to identify the changes in the glacier from 1985-2014 due to climate change. In essence the glaciated basin is transitioning to an alpine lake basin, quickly.

Topographic map of the Big Bend Glacier area.

In 1985 the glacier extends to the big bend in the valley marking its eastern end, red arrow. the yellow arrow indicates an area near 1800 m where the glacier extends across the valley. In 1992 there has been little retreat but evident thinning is leading to lake formation at the terminus and narrowing of the glacier at the red arrow. In 2002 thinning is leading to expansion of a proglacial lake both west and south of the red arrow. The terminus retreat has still been limited, thinning is evident at the yellow arrow.

In 2013 a new alpine lake that is approximately 1 km long has formed, as the terminus area of the glacier has collapsed. In 2014 an area of bedrock and a small lake has developed at the yellow arrow. There is no retained snowpack below the yellow arrow in 2013, and no retained snowpack in at all in 2014. This will likely be the case in 2015 as well. This glacier has a lower top elevation than most in the region and will be more impacted by the warm winter conditions and high snowline of 2015. The retreat from 1985 to 2014 has been 1.1 km. This is 40% of the entire glacier length gone in 30 years. The lake itself has a deep blue color suggesting limited glacier sediment input, further indicating a lack of motion of the glacier currently or in the near past.

The glacier retreat has been more extensive than Stave Glacier or Snowcap Glacier to its east. Koch et al,(2009) observed a widespread retreat and glacier area loss in Garibaldi Provincial Park just to the west, with 20% area loss from 1988-2005. Place Glacier is a short distance north of Big Bend Glacier has its mass balance has lost an average of 25 m of water equivalent (28 m ice) thickness since 1984, see bottom chart. This has been higher but similar in trend to other glaciers in the region. Big Bend will disappear soon just as we obsserved already happened at Milk Lake Glacier, North Cascades, Washington.

1985 Landsat Image

1992 Landsat Image

2002 Landsat Image

2013 Landsat Image

2014 Landsat Image

North American cumulative glacier mass balance graph

Midui Glacier, Tibet, China: Retreat and Terminus Collapse 1995-2014

On June 2, 2015May 3, 2024 By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations, Himalaya glacier retreat

Midui Glacier is 7 km from the G318 National Highway in China and 2 km from Midui village, hence the lake near the terminus is often visited. The glacier is near the headwaters of Yarlung Tsangpo. Glaciers in this region have experienced significant retreat and area loss as noted by the second China Glacier inventory. This compared glacier area from the 1950’s, 2002 and 2010, Liu et al (2013) noted that glacier area has declined 13%. The Midui Glacier was advancing as recently as 1964 when it emplaced an advance moraine (Xu et al, 2012). This is a region where Li et al (2011) noted that increasing temperature, especially at altitude, the fronts of 32 glaciers have retreated, mass losses of 10 glaciers have been considerable, glacial lakes in six regions have expanded and melt water discharge of four basins has also increased. This is further documented by an inventory of 308 glaciers in the Nam Co Basin, Tibet, where an increased loss of area for the 2001-2009 period, 6% area loss (Bolch et al., 2010) was observed. The nearby Yemayundrung Glacier retreat is similar. Here we examine changes in this glacier using Landsat imagery and Google Earth from 1995-2014.

1995 Landsat image

2014 Landsat image

In the Landsat images above in 1995 the glacier terminates in a proglacial lake at the red arrow. A ridge separates two tributaries each with an icefall creating ogives, purple arrow. There are ogives below a pair of icefalls at the yellow arrow. The tributaries are separated by a medial moraine orange arrow. By 2014 retreat has led to expansion of the lake at the terminus. The retreat is 300 meters during this 20 year period. The icefall on the right, east side of the glacier, is no longer producing significant ogives and the bare glacier ice has been replaced with extensive debris cover, yellow arrow. Both the ridge and medial moraine separating the tributaries have expanded in width as the glacier has thinned.

A series of comparison images from Google Earth in 2001 and 2014 further illustrate the changes noted above.

In the first pair the terminus change and lake expansion is evident at the red arrow. Debris cover expansion at the lateral moraine area with thinning of the eastern tributary is notable at the yellow arrow.

The second pair is the terminus reach. A series of depressions are noted with each yellow arrow, indicated by concentric crevassing. This indicates collapse due to a subglacial basin/lake. Further this indicates a stagnant collapsing terminus area in the lower 1.5 km of the glacier.

The last pair is the icefall region indicating reduced crevassing below the lefthand icefall, pink arrow and the expanding medial moraine yellow arrow. It is clear that this glacier is going to continue to retreat in the coming decades, and the rate is going to increase in the near future as the collapsing sections of the terminus melt away. There is still considerable glacier area that remains snowcovered each year, and it can survive current climate and some additional warming. The snowline on the glacier is at 5000-5100 m and the head of the glacier is at 6100 m.

Midui Glacier comparison from Google Earth

Midui Terminus comparison from Google Earth

Midui Icefall comparison from Google Earth

Retreat forms Embayment at Kropotkina Glacier in Novaya Zemlya

On May 28, 2015May 3, 2024 By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations

Kropotkina Glacier is a tidewater glacier on the southeast coast of Novaya Zemlya that drain into Vlaseva Bay. The glaciers terminate in the Kara Sea and has been retreating like all tidewater glaciers in Novaya Zemlya LEGOS, 2006 . The map shown below from this project indicate the lack of an embayment in 1952, red dashed line and limited retreat from 1952-1988, with 1988 being the yellow line. Carr et al (2014) identified an average retreat rate of 52 meters/year for tidewater glaciers on Novaya Zemlya from 1992 to 2010 and 5 meters/year for land terminating glaciers. Here we examine Landsat imagery from 1988 to 2013 to identify changes in Kropotkina Glacier.

In each image the colored arrows are in the same location. In 1988 the terminus is just beyond the red arrow indicating a peninsula on the east side of the terminus. The yellow arrow indicates a lake beyond an eastern terminus lobe with limited drainage down a river adjacent to the glacier, purple arrow. Two smaller glacier termini are joined at the green arrow. By 1998 there is a minor retreat of the main terminus on both the east and west side. Little change is seen elsewhere. By 2011 a substantial embayment has developed above the red arrow. Retreat is limited on the western side of the terminus. The eastern terminus lobe has retreated as well and the drainage channel adjacent to the glacier is less restricted leading to a less extensive lake. The lake is mostly filling the region occupied by ice 13 years before.

In 2014 there is cloud cover over much of the glacier but the terminus is clear. The easternmost terminus lobe is collapsing, and is not surrounded by a lake, yellow arrow. The purple arrow drainage river is no longer necessary as there is lake connectivity. The main terminus to the east has retreated to the entrance to the lake for the eastern terminus lobe, this a 2.8 km retreat. The western side of the glacier remains aground on a peninsula, but has receded 500 m. How long before this part of the terminus to retreats into the expanding embayment. An are of more 7 square kilometers has gone from glacier ice to embayment in the last 25 years, almost all within the last 13 years. The retreat has mainly been via calving, and with an expanding calving front and reduced pinning points along the margin, the rapid retreat and area loss is not over. The beginning of rapid retreat coincides with the onset of rapid decline in sea ice extent in the Kara Sea (Perovich et al., 2014).

This ongoing retreat is illustrated by Krivosheina, Chernysheva, Roze and Sredniy and Taisija Glacier also in northern Novaya Zemlya.

1988 Landsat image

1998 Landsat image

2011 Landsat image

2014 Landsat image

Mack and Velkena Glacier Retreat Novaya Zemlya 1988-2013

On May 26, 2015May 3, 2024 By mspeltoIn glacier climate change, Glacier Observations

Mack and Velkena Glacier are tidewater glaciers on the northwest coast of Novaya Zemlya that drain into Legzdina Gulf. The glaciers terminate in the Barents Sea and have been retreating like all tidewater glaciers in northern Novaya Zemlya LEGOS, 2006). The map shown below from this project indicate the glaciers joined in 1952 and 1976 and separated by less than 1 km in 1988. Carr et al (2014) identified an average retreat rate of 52 meters/year for tidewater glaciers on Novaya Zemlya from 1992 to 2010 and 5 meters/year for land terminating glaciers. This ongoing retreat is illustrated by Krivosheina, Chernysheva, Roze and Sredniy; and Taisija Glacier also in northern Novaya Zemlya. Here we examine Landsat imagery from 1988 to 2013 to identify changes in Mack and Velkena Glacier.

Map of Velkena and Mack Glacier area from Sharov et al (2006) at LEGOS. The red dashed line is 1952, green dashed is 1976, yellow dashed is 1988 and solid purple is 2001.

The arrows and letter in each image are at fixed locations: the yellow arrow indicates the peninsula where Velkena and Mack Glacier separated. The red arrow indicates the 1998 eastern terminus of Mack Glacier and the purple arrow indicates the 1988 position of the western terminus of Velkena Glacier. The green C and pink C respectively indicate areas of intense crevassing in 2013. In 1988 the glaciers are separated by just 500 m adjacent to yellow arrow, the crevassing is limited at both C’s. In 2000 Velkena and Mack Glacier are now separated by 1.4 km, retreat of Mack from the red arrow is 500 m and retreat of Velkena Glacier from the purple arrow is 600 m. In 2006 Mack Glacier has retreated 1000 meters from the red arrow, and Velkena Glacier has retreated 1200 meters from the purple arrow. Extensive crevassing is not yet evident at C.

In 2011 at both locations crevassing is readily apparent in the satellite imagery. Retreat has continued for both glaciers 1250 m for Mack Glacier from red arrow and 1600 m for Velkena Glacier from purple arrow. In 2013 the extensive crevasses zone (C) for both glaciers is within 500 m of the icefront. The increase in crevassing is indicative of glacier acceleration, this is likely due to a steeper slope of the glacier near the current terminus. This also suggests retreat will remain rapid in the near future. Retreat of Mack Glacier from 1988-2013 has been 1.8 km on the east side, red arrow, and 2 km on the west side. On Velkena Glacier retreat has been 2.8 km on the west side, purple arrow, and 1 km on the east side. Both glaciers have been receding at a rate greater than the 50 meters/year noted as average by Carr et al. (2014). Anomalies for sea surface temperature along this section of sea ice free Novaya Zemlya are well above average in May 2015, which should lead to continued calving retreat.

1988 Landsat Image

2000 Landsat Image

2006 Landsat Image

2011 Landsat Image

2013 Landsat Image

Nooksack River: Glacier Runoff Maintains Suitable Aquatic Conditions for Salmon

On May 21, 2015May 3, 2024 By mspeltoIn glacier climate change, Glacier Observations, North Cascade Glaciers

Illustration from Megan Pelto above left

Sholes Glacier from our runoff measurement station above right.

Glaciers are a critical water resource in the North Cascades of Washington for hydropower, irrigation , municipal supply and aquatic life. In dry summers glaciers play an even larger role in the overall water budget and maintaining suitable aquatic conditions. The summer of 2015 will pose particular challenges due to the drought emergency that is likely to persist and we will be investigating the role glaciers play. During the last three years in an ongoing study with the Nooksack Indian Tribe we have been working on quantifying the role glaciers play in that watershed. Glaciers comprise the headwaters of the Nooksack River and are a critical source of summer discharge and greatly influence summer stream temperatures. There are nine species of salmon in the watershed that the Nooksack Indian Tribe depends on for cultural, subsistence, and economic uses. Climate change is an additional new threat to salmon that has caused and will continue to cause an increase in winter flow, decreased summer baseflow, and increased summer water temperatures as noted by (Isaak et al, 2011). Abatzaglou et al (2014) note a reduction in summer and autumn precipitation coupled with increased potential evapotranspiration causing larger climatic water deficits over the past four decades in the Pacific Northwest.

Nooksack Watershed map with Mount Baker glaciers.

This post will focus on the changing impact of glaciers on streamflow and the evolving water temperature threat. The Nooksack River watershed has three significant watersheds, South Fork, Middle Fork and North Fork. The South Fork has no glaciers. The Middle Fork has four significant glaciers and 2% of the watershed area above the USGS gage is glaciated. The North Fork has 12 significant glaciers that cover 6% of the watershed area above the USGS gage. This difference in glacier cover allows identification of the role of glaciers when combined with measurements of melt on and runoff from the glaciers. Here we examine stream discharge and water temperature at USGS gages on each stream to illustrate the different response to 12 warm weather events during the summers of 2009, 2010, 2012 and 2013. During each of these periods we have, along with Oliver Grah and Jezra Beaulieu, working for the Nooksack Tribe, been observing the ablation and runoff directly from the glaciers. The largest area of glaciers are those on Mount Baker, a strato volcano that is the highest mountain in the North Cascades. Pelto and Brown (2012) note that terminus observations on the nine principal Mount Baker glaciers, 1984–2009, indicate retreat ranging from 240 to 520 m, with a mean of 370 m or 14 m/year. Pelto and Brown (2012) observed that this is the result of a sustained mass balance loss averaging -0.5 m/year during the 1990-2010 period. This equates to an 11-m loss in glacier thickness, 12–20% of the entire 1990 volume of glaciers on Mount Baker. This summer we will for the 32nd consecutive year be measuring glacier mass balance on Mount Baker.

Measuring snow depth in crevasse on Mount Baker glacier.

Jezra Beaulieu at Runoff measurement Gage

During each of these warm weather events ablation was measured on glaciers in the basin. For stream discharge, a 10% increase is set as the key threshold for significant response to each warm weather event. For the North Fork 10 of 12 warm weather events exceeded the limit, in the Middle Fork 4 of 12 events had a significant response and for the South Fork none of the 12 events led to a 10% flow increase. It is apparent that warm weather events increase glacier melt, thus enhancing flow in the North Fork. In a basin without glacier runoff the hydrologic system consistently experiences reduced discharge.

2009 stream discharge variation of the three Nooksack forks, warm water events within ellipse.

2010 stream discharge variation of the three Nooksack forks, warm water events within ellipse.

For water temperature, an increase of 2° C is the threshold of significance used for response to warm weather events. In each the North Fork and Middle Fork, 2 of 12 events exceeded this threshold, and for the South Fork 12 of 12 events exceeded this threshold, each event is a gold ellipse on the charts below. Warm weather events consistently generate a significant increase in stream water temperature only in the non-glaciated South Fork Basin. During 6 of these 12 warm events, runoff measurements below Sholes Glacier and ablation measurements on Sholes and Easton Glacier indicate daily ablation ranging from 0.05-0.06 meters per day, which for the North Fork currently yields 9.5-11 m3/second. This is 40-50% of the August mean discharge of 24 m3/second, despite glaciers only covering 6% of the watershed. Increased glacier discharge largely offset the impact of increased air temperature on stream water temperature during the warm weather events. In the charts below note the red line with diamond markers that is the South Fork stream temperature and the in the graph above the top brightest blue line that is North Fork discharge and what happens during the warm events, gold ellipses. Also note the South Fork discharge bottom blue line in the graph above does not respond nor does the North Fork stream temperature red line with triangles, below.

The frequency of significant response of each watershed to the 12 warm weather events.

Daily and cumulative ablation during the 2014 melt season.

2009 Temperature record for the South Fork, North Fork and Middle Fork, warm water events within ellipse.

2010 Temperature record for the South Fork, North Fork and Middle Fork, warm water events within ellipse.<

As the glaciers continue to retreat the North Fork will trend first toward the more limited impact of the Middle Fork and then the highly sensitive South Fork where warm weather leads to declining streamflow and warming temperatures. Our ongoing measurements of daily runoff and daily streamflow below Sholes Glacier allow determination of the contribution of glaciers to the North Fork Nooksack, which peaked in 2014 at 80% of total streamflow. Reductions in glacier runoff will put stress on the salmon in the watershed. The Washington Dept of Fish and Wildlife monitors the salmon population, which in the North Fork migrate 40 km upstream of the junction with Nooksack River to Nooksack Falls. The salmon population which is threatened, shows no sign of recovery in the last decade, the good returns in 2002 reflect good water conditions in 1999-2000 for salmon fry. Continued glacier loss and reduced summer streamflow will lead to a situation similar to the Skykomish River where the number of low flow days has sharply increased. The retreating glaciers include the Sholes, Roosevelt,Deming and Mazama.

Glacier runoff in the North Fork Nooksack in 2014, product of observed ablation and glacier area, also percent of total flow.

WFDW Governor’s Salmon Recovery Office data for North Fork Nooksack.

Skykomish River, Washington Reduced Minimum River Flow and Glacier Retreat

On May 19, 2015May 3, 2024 By mspeltoIn glacier climate change, Glacier Observations, North Cascade Glaciers

Fording the outlet of Blanca Lake, headwater North Fork Skykomish River.

The focus this spring has been on the developing drought in Washington as a result of record low snowpack, the winter was a record warmth though not dry. The focus of this article is on another component of many alpine watersheds, glacier runoff, both the ameliorating role and their reduced ability as they shrink to augment flow during low flow periods. 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 of 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. This is the first of two posts looking at the response of specific alpine watersheds to glacier change and glacier runoff, the second will look at the Nooksack River.

Watersheds in mountainous Pacific Northwest are comprised of pluvial, nival and glacial segments. The pluvial segments have peak flows in the winter due to the winter storm events (Dery et al., 2009). Nival streams peak in the May and June with the high snowmelt, and glacially fed streams peak in July and August during peak glacier melt (Pelto, 2008; Dery et al., 2009). The loss of glaciers from a watershed then reduces streamflow primarily during minimum flow periods The amount of glacier runoff is the product of surface area and ablation rate. The glacier retreat and loss of glacier runoff has been quite pronounced in the Skykomish River Basin, North Cascades, Washington from 1950-2014 (Pelto, 2011). This summer we will return to make observations on 4 glaciers in this watershed for the 32nd consecutive year. We will be measuring flow with the Nooksack Indian Tribe again this year below glaciers, and we will observe the drought impact on the glaciers and downstream.

Skykomish Basin Map-Light blue arrows indicate the four main glaciers: 1=Columbia, 2=Hinman, 3=Foss, 4=Lynch

An analysis comparing USGS streamflow records for the Skykomish River at Gold Bar for the 1950-1985 to the 1985-2009 period indicates that during the recent period the Skykomish River summer streamflow (July-September) has declined 26% in the watershed, spring runoff (April-June) has declined 6%, while winter runoff (November-March) has increased 10% (Figure 1). The reduction of the glacial melt component augmenting summer low flows is already resulting in more low-flow days in the North Cascade region. In the Skykomish River watershed from 1958-2009 glacier area declined from 3.8 km2 to 2.1 km2, a 45% decline (Pelto, 2011). Columbia, Foss, Hinman and Lynch Glacier, the primary glaciers in the basin, declined in area by 10%, 60%, 90% and 35% respectively since 1958. Annual mass balance measurements completed from 1984-2009 on Columbia, Foss and Lynch Glacier indicate a mass loss of 13.1 m w.e. Despite 15% higher ablation rates during the 1985-2009 period, the 45% reduction in glacier area led to a 38% reduction glacier runoff between 1958 and 2009. This means less glacier runoff in late summer.

Change in seasonal discharge in the Skykomish River. Increase in winter, decrease in summer.

Foss Glacier retreat.

Lynch glacier Retreat

Hinman Glacier, view from former terminus

Columbia Glacier losing its snowcover in the accumulation zone.

Columbia Glacier Retreat. Detailed report.

A key threshold of in-stream flow levels considered insufficient to maintain short term survival of fish stocks is below 10% of the mean annual flow (Tennant, 1976). For the Skykomish River 10% of mean annual flow is 14 m3s-1. In the Skykomish River from 1950-2013 there have been 230 melt season days with discharge below 14 m3s-1. Of these 228, or 99% of the low flow days, have occurred since 1985. The loss of 30-40% of the glacier runoff is a key reason for the onset of critical low flow days. Of more concern for aquatic life is the occurrence of extended periods of low flow (Tennant, 1976). From 1929-2009 in the Skykomish River basin there have been eight years where streamflow dropped below 14 m3s-1 for 10 consecutive days during the melt season, 1986, 1987, 1992, 1998, 2003, 2005, 2006 and 2007. It is likely that 2015 will join this list.

Number of days when flow fell below 10% of the long term mean annual flow. Only one day from 1950 to 1985 met this criteria. Precipitation has not declined substantially during this interval, hence earlier snowmelt, reduced glacier runoff and greater evapotranspiration must be causing the increase in late summer low flow periods. The 38% reduction in glacier runoff did not lead to a significant decline in the percentage summer runoff contributed by glaciers under average conditions; the contribution has remained in the range of 1-3% from July-September. The glacier runoff decline impacted river discharge only during low flow periods in August and September. In August, 2003 and 2005 glacier ablation contributed 1.5-1.6 m3s-1 to total discharge, or 10-11% of August discharge. While declining glacier area in the region has and will lead to reduced glacier runoff and reduced late summer streamflow, it has limited impact on the Skykomish River except during periods of critically low flow, below 14 m3s-1 when glaciers currently contribute more than 10% of the streamflow.

For 2015 the lack of snowpack in the Skykomish Basin is evident from a comparison of images from April 20th 2015 and June 4th, 2014. Snowpack during 2014, an average winter, was higher in mid-June than in mid-April in 2015. Arrows in each side by side are in same location. This indicates that the pluvial and nival segment of flow to the Skykomish River will be at a minimum late this summer. Currently flow at the USGS gage in Gold Bar is 28% of normal at 2050 CFS, which is an all time low for the record that begins in 1929, previous low in 1977 at 2755 CFS. The river has not reached 2750 CFS the entire month of May. Glacier flow has continued to decline with area extent losses. This combination makes it likely, that the Skykomish River will have an extended period of low flow this summer and into the fall. If the summer is drier than average, flows will likely reach a new minimum.

Snowpack comparison in the area of the North Fork Skykomish near Columbia Glacier (C) in April 2015 compared to a snowier June, 2014.

Snowpack comparison in the area of the South Fork Skykomish near Lynch Glacier (D) in April 2015 compared to a snowier June, 2014.

Terminus image of Columbia Glacier in March 2015 (below) with less overall snow than in the image above from August, 2013. (picture below from Rowan Stewart)

Developing Instability of Verdi Ice Shelf, Antarctica: Extensive Rift Formation

On May 17, 2015May 3, 2024 By mspeltoIn Antarctic Glacier retreat, glacier climate change, Glacier Observations

The Verdi Ice Shelf is a small ice shelf on the Beethoven Peninsula of Alexander Island on the Antarctic Peninsula. Its small size limits its global importance, but it does provide an excellent example of the rapid development of rifting that indicates potential instability. An ice shelf is a floating portion of a glacier, it buttresses glaciers that drain into it and is in turn buttressed by pinning points along the margin and within the ice shelf provided by islands and ice rises. Ice Shelf processes are well described by Davies (2014).

Cook and Vaughan (2010) observed that in recent decades, seven out of twelve larger ice shelves around the Antarctic Peninsula have retreated significantly or been almost entirely lost. This is a pattern of behavior that indicates the ability of ice shelves to collapse entirely or significantly in a short period of time. A recent paper by Holland et al (2015) noted that the much larger Larsen C Ice Shelf is thinning from above and below. The thinning of an ice shelf is the essential pre-conditioning for collapse (Pelto, 2008). NASA last week also predicted the demise within five years of the remaining portion of Larsen B.

Holt et al (2013) outlined several key glaciological characteristics as typically preceding recent ice shelf collapses:

(1) Sustained ice-front retreat, resulting in a frontal geometry that bows inwards towards its centre from both lateral pinning points (Doake et al., 1998);

(2) Continued thinning from atmospheric or oceanic warming (Shepherd et al., 2004);

(3) An increase in flow speed:

(4) Structural weakening, such as rifting along suture zones (Glasser and Scambos, 2008), and also rifting transverse-to-flow due to changing stress regimes within the ice shelf (Braun et al., 2009). Braun et al (2009) note that for Wilkins Ice Shelf just to the north of Verdi Ice Shelf surface melt and drainage of melt ponds into crevasses were not relevant for break-up. Increased buoyancy forces from thinning caused rift formation before the break-up in February 2008 was the key. Glasser et al (2011) examined the Röhss Glacier following the 1995 collapse of the Prince Gustav Ice Shelf, Antarctic Peninsula identifying the development of numerous structural discontinuities: rifts, crevasses and melt ponds on the ice shelf before the collapse.

Here we examine Landsat imagery of Verdi Ice Shelf from 2000-2014. To identify both frontal changes and structural changes.

Map of the Verdi Ice Shelf region taken from the USGS Palmer Land Map.

The above map indicates retreat of 1.5-2 km of the ice front from 1973-2001 and that the front is bowed inward at the center meeting the first criteria noted above. In each image the yellow arrow indicates the 2001 ice front of Verdi Ice Shelf on the northeast side. The pink dots in each image is the complete ice front. The red arrow indicate large rifts visible in the Landsat images, which have a 30 m resolution. In 1999 there are no major visible rifts. There are a few minor rifts close to the ice front. The maximum length of the ice shelf is 14.5 km. In 2001 the frontal position has not changed significantly and no significant rifts are visible. In 2003 the ice front has retreated 0.5-1 km, there are two minor visible near the ice front, to the left (west) of the yellow arrow. In 2013 and 2014 the maximum length of the ice shelf has declined to 12.5 km, a 2 km retreat in 15 years. More importantly there are now six significant rifts in the ice shelf, including two well back of the ice front. The rifts range from 2-4 km in length, a significant portion of the entire ice shelf width. The most inland rifted area noted occurs at the inland edge of the ice shelf and instead of a single rift is an area of numerous smaller rifts. The rapid development of the rifts suggests the ice shelf has thinned to a point of instability. This does not mean it will disintegrate entirely or immediately, but does suggest that most of the ice shelf is poised to collapse in the next decade.

Similar recent ice shelf changes reviewed are: Jones Ice Shelf and Wordie Ice Shelf. The understanding of the processes has taken detailed field work by many field teams. Examples being the LARsen Ice Shelf System, Antarctica (LARISSA) team and the British Antarctic Survey supported research at James Ross Island and Wilkins/Larsen Ice Shelf.

1999 Google Earth image

2001 Landsat image

2003 Landsat image

2013 Landsat image

2014 Landsat image

Retreat of Grewingk Glacier, Alaska 1986-2014

On May 13, 2015May 3, 2024 By mspeltoIn alaska glacier retreat, climate change glacier retreat, glacier climate change, Glacier Observations2 Comments

Grewingk Glacier drains west toward the Kachemak Bay, Alaska terminating in a proglacial lake in Kachemak Bay State Park. The glacier drains an icefield on the Kenai Peninsula, glaciers draining west are in the Kenai Fjords National Park. The glaciers that drain east toward are in the Kenai Fjords National Park, which has a monitoring program. Giffen et al (2008) observed the retreat of glaciers in the region. From 1950-2005 all 27 glaciers in the Kenai Icefield region examined are retreating. Giffen et al (2008)observed that Grewingk Glacier retreated 2.5 km from 1950-2005. Here we examine Landsat imagery from 1986-2014 to illustrate the retreat of the glacier. The icefront continues to calve into the expanding pro-glacial lake.

1951 based USGS Topographic map Seldovia C-3

The red arrow is the 1986 terminus location at the midpoint, the yellow arrow is the 2014 mid-point terminus location. In 1951 the glacier extended beyond the peninsula at the red arrow into the wider portion of the lake. By 1986 the glacier had retreated into the narrow section of the lake extending east into the mountains, the southern margin of the terminus is further advanced than the northern margin. The orange dots indicate discoloration of the glacier surface from volcanic ash deposited on the glacier surface from Augustine Volcano in 1986. In 1989 there is not a marked change. In a 1996 Google Earth image, there is considerable icebergs indicating a recent collapse of a section of the terminus. The pink arrow indicates concentric crevasses, indicating a depression, the red line is the terminus in 1996 and the brown line the 2003 terminus.

By 2001 the terminus has retreated m, and the glacier front is now oriented north-south across the lake. In 2003 the depression from 1996 now has a small supraglacial lake, the terminus has retreated 500 m on the southern margin and 200 m on the northern margin. In 2013 the glacier has retreated an additional 600 m and the southern margin has now receded further upvalley than the northern margin. Blue arrows indicate direction of glacier flow. By 2014 the glacier has retreated 1.4 km since 1986, 50 m per year. There is an increase in the glacier slope 2.5 km above the terminus where crevassing increases. This suggests the lake will end by or at this point, which would then lead to a reduction in retreat rate.

This retreat follows that of Pederson Glacier, Four-Peaked Glacier and Spotted Glacier. The continued reduction in glacier size leads to changes to the Kachemak Bay estuary. Kachemak Bay is the largest estuarine reserve in the National Estuarine Research Reserve System. It is one of the most productive, diverse estuaries in Alaska, with an abundance of Steller sea lions, seals, sea otters, five species of Pacific salmon, halibut,herring, dungeness crabs and king crabs (NERRS, 2009). The estuary salmon fishing industry is, one of Kachemak Bay’s most important resources and livelihoods.

1986 Landsat Image

1989 Landsat Image

1996 Google Earth Image

2001 Landsat Image

2003 Google Earth Image

2013 Landsat Image

2014 Landsat Image

Disaggregation of Austria’s Third Largest Glacier, Obersulzbach Kees

On May 11, 2015May 3, 2024 By mspeltoIn glacier climate change, Glacier Observations, Uncategorized

The Obersulzbach Glacier, is situated in the uppermost part of the Obersulzbach Valley, which feeds the Salzach River system in Austria. The glacier drains the northeastern flank of Großvenediger. The glacier was the third largest glacier in Austria in the 1980’s, but in the last several decades separated into five distinct sections. Now that it is in five parts, should it be listed as such?

Yes, given that the Austrian Glacier Inventory has reclassified the glacier as five separate glaciers (Fischer et al, 2014). In this post they are numbered 1=Krimmlertorl Kees, 2=Obersulzbach Kees, 3=Bleidacher Kees, 4=Sulzbacher Kees, 5=Venediger Kees.

Nick Fisher sent me a map of the glacier prepared by the Austrian Military in the early 1930’s this is compared to the GE image of the glacier from 2012, below. According to this map, in 1934 the ice was at least 150 m deep over the current lake surface, where all the glacier streams united before heading down the ice fall. In 1934 the five branches of the Obersulzbach all joined and continued downglacier past a prominent rib on the east side of the glacier, light blue arrow, to terminate at 1980 meters, green arrow. The two western most glaciers Krimmerlertorl and Obersulzbach on the images, were joined at the pink arrow in 1934 and are well separated in 2012. At the orange arrow in 1934 Bleidacher (3) flowed over a steep cliff and joined the other segments. Today the glacier section ends at the top of a steep cliff. Glacier Sulzbacher and Venediger are the largest and easternmost draining the actual slopes of Großvenediger. They joined the other segments in 1934. By 1988 they had retreated to the red arrow but the two were still joined, by 2012 they had separated at the yellow arrow. Hence, we now have separate glaciers that formerly joined together. The World Glacier Monitoring Service reports indicate this glacier retreated 140 meters from 1991-2000 and 345 m from 2001-2010, a substantial increase. Here we examine Landsat imagery from 1988, 1998, 2012, 2013 and 2014 to identify the retreat andand separation of the glacier into. By 1998 a small lake less than 100 m long has formed at the end of the glacier, blue arrow.

Map of the Obersulzbach Region in 1934 from Nick Fisher

Google Earth image from 2012

In 1988 there is no lake visible at the end of the main terminus. The glacier has retreated 1.4 km since 1934. At the pink arrow glacier Krimmerlertorl and Obersulzbach are still joined in 1988. Glacier Sulzbacher and Venediger are also still joined at the yellow arrow and terminate at the red arrow. Glacier section Bleidacher has become detached.

By 1998 Krimmerlertorl and Obersulzbach are separated but the eastern glaciers Sulzbacher and Venediger are still joined at the yellow arrow. No lake yet exists at the terminus. Obersulzbach Glacier receded in a narrow bedrock basin since the late 1990’s and a shallow lake, Obersulzbach-Gletschersee, has formed since 1998 (Geilhausen et al, 2012). They observed that in 2009, the lake had an area of 95,000 m2 with a maximum depth of 42 m.

By 2013 all the glacier segments are separate. By 2013 the lake, Obersulzbach-Gletschersee,has grown to a length of 450 m and a with of over 200 meters. The retreat from 1988-2013 of glaciers Krimmerlertorl=0.8 km, Obersulzbach=0.6 km, Bleidacher=1.3 km, Sulzbacher=1.4 km, Venediger=1.6 km. The 2014 image is not as clear, but further retreat did occur. The Austrian Alpine Club 124th annual survey indicated 86% of Austrian glaciers retreated from 2013-2014.

The Salzach is fed by many glaciers covering over 100 square kilometers (Koboltschnig and Schoner, 2011). These glaciers melt all summer providing considerable runoff to the numerous hydropower projects along the Salzach, that can produce 260 MW of power. The Verbund Power Plant producing 13 MW is seen below, at blue arrow. Glacier area loss will lead to declines in summer runoff. A mass balance program has been started on Venediger Kees.

This glaciers retreat fits the pattern of other glaciers in the Austrian Alps, Oberaar Glacier, Rotmoosferner and Ochsentaler.

1988 Landsat image

1998 Landsat image

2013 Landsat image

2014 Landsat image