Mittelaletsch Glacier Retreat, Switzerland

Mittelaletsch Glacier was a tributary to the Alps largest glacier Grosser Aletsch, until separation in 1990. The map of the glacier represents changes in the glacier from 1926 to 1957, indicating the connection of the two glaciers at that time. By 1970 Mittel had separated from Grosser, and experienced 420 m of retreat from 1970 to 2000 as noted by the Swiss Glacier Monitoring Network. mittel 1957
Map showing 1957 glacier extent with elevation changes from 1926 in yellow.

Here we examine changes in the glacier using Landsat imagery from 1990 to 2013. In each image an upper and lower green arrow point to the same location where expanding bedrock areas are separating the upper and lower portion of the glacier. Point A is at the lower end of a prominent rock rib. In 1990 the glacier ends at the red arrow separated from Grosser Aletsch by 600 m. At the lower green arrow the glacier is flowing across this slope contributing snow and ice to the lower glacier. In 1999 the area of exposed bedrock between the upper and lower glacier has expanded by at least 500 m at both green arrows. By 2007 Google Earth imagery indicates a continued expansion at the lower green arrow. The glacier terminates at the yellow arrow 1050 m from a connection to the Grosser Aletsch Glacier. The lower 1 kilometer of the glacier is stagnant as seen in the closeup view of the terminus, pink arrow indicates start of stagnant section. In 2013 the glacier has retreated 1400 m from the Grosser Aletsch Glacier, terminating at yellow arrow versus 1990 terminus red arrow. The margin of the Grosser Aletsch has contracted 150-200 m, hence the actual retreat since separation is 1200-1250 m. By 2013 at the lower green arrow the bedrock strip separating this section of the upper and lower glacier has expanded to a length of 1 km. This is equivalent to a company losing income from an important division, or a family losing one income stream. The lower glacier is recieving less snow and ice contribution and will continue to retreat, quickly loseing the stagnant area the comprises the lowest 700-100 m of the glacier. Jouvet et al (2011) reconstruct the behavior of the Aletsch Glacier system to various climate scenarios and find that any scenario leads to 2 km of retreat by 2040 for Grosser Aletsch and somewhat less for Mittelalestch. This glaciers behavior is similar to that of nearby Gauli and Oberaar. mittel 1990
1990 Landsat image

mittel 1999
1999 Landsat image

mittelaletsch ge
2007 Google Earth Image

mittelaletsch profile
2007 Google Earth image

mittel 2013
2013 Landsat image

Cavagnoli Glacier Retreat, Swiss Alps

Ghiacciaio dei Cavagnoli (Ghiacciaio dei Cavagnöö) drains south into Lago dei Cavagnoli (Lago dei Cavagnöö), which is impounded by a dam that was 111 meters high. This hydropower plant provides 174 MW of power. The glacier itself has separated into five separate ice masses that are each melting quickly away. The Swiss Glacier Monitoring Network has observed the annual retreat of this glacier since 1980. A chart of this retreat from the data of the Swiss Glacier Monitoring Network is below. The total retreat of the main ice mass has been 343 meters. The top of the glacier has also been retreating this is a symptom of a glacier that will not survive (Pelto, 2010). The glacier as viewed from below and from directly above in Google Earth Imagery indicates a thin glacier with few crevasses. The five separate ice masses are all indicated by stars. This glacier has no accumulation zone in 2009. This has become a reoccurring pattern for this glacier, and also is a sign of a glacier that cannot survive. This glacier is a small relic of its former mapped extent. when the glacier was a single ice mass. Today the largest ice mass is 0.4 square kilometers and none of the ice masses appear destined for surviving. On the main ice mass there is a meltwater stream from the top to the bottom of the glacier indicating that even the top of the glacier is usually snow free by summer’s end. This glacier is in similar shape to the glaciers in the Rotondo area just to the north

Chüebodengletscher and Ghiacciaio del Pizzo Rotondo, Switzerland nearly gone

Chüebodenhorn is 3,070 meter high in the Lepontine Alps. The Ghiacciaio del Pizzo Rotondo lies at the foot of its north face and Chüebodengletscher is on its south side. Chüebodengletscher is confined to a small cirque, and currently ends in a lake . In several recent years including 2010 the glacier lost all of its snowcover. The glacier is currently 500 meters long and has an elevation range of 75 meters. The lake which fringes the glacier will turn into a circular alpine lake as the glacier melts away. At present the crescent shaped lake is 140 meters wide. The annual layers in this glacier are evident much like tree rings, that the are all emergent at the surface indicates that all the snow and firn that is supposed to cover most of a glacier at the end of the summer, has been lost from all of the glacier. There are at least 75 annual layers evident. The youngest layer (y) is at the top of the glacier and oldest (o) at the bottom.
Ghiacciaio del Pizzo Rotondo is a thin slope glacier. This glacier also has a short elevation span of 80 meters from the terminus to its head in a distance of 500 meters. The glacier is a slope glacier that has little apparent thickness. The glacier will be lost faster than the thicker Chüebodengletscher. Ghiacciaio del Pizzo Rotondo also has lost all of its snowcover, and without a persistent and consistent accumulation zone it cannot survive. These two glaciers are losing mass like many neighboring such as the large Gries Glacier monitored by the In the graph below From the Swiss Glacier Monitoring Network the cumulative mass loss of Gries Glacier has been 20 meters. Swiss Glacier Monitoring Network. This mass loss of Swiss Glaciers led to 86 of the 95 glacier observed to retreat, while six were stationary and three advanced. The lack of an accumulation zone indicates that the glaciers will follow the path of Presena Glacier and Dosde Glacier unlike Oberaar Glacier which retains an accumulation zone.

Oberaar Glacier Retreat and Hydropower

The Oberaar Glacier at the headwaters of the Aare River is one of the key glaciers whose runoff feeds the complex hydropower system built by Kraftwerke Oberhasli (KWO) from the 1930’s thorugh 1979. The Glacier ended in the artificial lake Oberaarsee created by damming the glacier outflow in 1932. Oberaarsee (O) is dominantly a glacier fed reservoir, which is evident in this 2002 image from Jürg Alean This dam is close to two other largely glacier fed reservoirs Grimselsee (G) and Raterichsbodensee (R). The upper watershed of the Aare provides ideal natural conditions for hydropower generation, abundant water, deep broad glacial valleys for water storage and a 1700 m elevation drop from the Oberaarsee down to Innertkirchen. KWO’s constellation of power plants, seven hydro dams, a natural lake and around 130km of water carrying pipes was completed only in 1979. The total output of the KWO system is 1100MW, equivalent of a large nuclear plant. The network that supplies 7% of the hydropower for Switzerland is fascinating as seen in the schematic below from KWO.
Oberaar Glacier has retreated 1500 meters since the building of the dam and now no longer reaches the shores of Oberaarsee. The glacier from 1953-1967 retreated at a rate of 42 meters per year, calving into the lake with the average depth of 17 meters. The presence of the lake enhanced retreat, the glacier velocity was 8 meters per year, while calving retreat was 42 meters per year. The lake did not cause the retreat though, as Gauligletscher the next glacier to the north has experienced a large retreat since 2000. The Swiss Glacier Commission’s retreat history indicate that by the 1970’s the glacier was in shallow water near the edge of the lake and retreat was minor. More recently though the lake is no longer enhancing retreat, the retreat rate has again risen to more than 20 meters per year from 1998-2010. The glacier has retreated 460 meters from the edge of Oberaarsee. By 2013 Landsat imagery indicates the glacier has retreated approximately 1 km from the lake, black arrow indicates terminus and red arrow the end of the stagnant zone. . oberaar 2013 The Swiss Glacier Commission monitored the glacier surface and found the lower section of the glacier below 2700 meters, thinned by 7.3 meters from 2001-2005 representing a volume loss of 13.5 million cubic meters. Given that lower glacier thickness averages somewhere close to 75-100 meters, this was 7-10% of the glacier lost in four years. Compared to the 1960’s the glacier near the terminus has slowed from 8 to 4 meters per year. It is evident that terminus tongue is thin nearly stagnant moving at 2 meters per year in 2005. The glacier thinning is rapid which is also indicated by the degree to which the lateral margin of the glacier is higher due to the higher debris cover. This occurs only during periods of rapid retreat. The retreat will continue due to the recent snow line rise that has reduced the area of the accumulation zone. The glacier has an icefall at 2800 meters and and above this at 3050 meters is a significant consistent accumulation zone; however not large enough to maintain the large lower elevation glacier tongue. This is similar to all Swiss Glaciers, the average mass balance from 2000-2010 has been consistently and substantially negative as reported to the WGMS, -0.8 meters per year. This has led to retreat of 98% of all glaciers in the Alps such as Maladeta, Italyand Ochsentaler in Austria. The Swiss have the best annual terminus survey system and the graph at bottom indicates the percent retreating in red, advancing in blue, and stationary in green. It is clearly a red tide. With glacier area loss the summer melt will decline and summer inflow to Oberaarsee will decline. The total annual inflow is determined by annual precipitation and is not changed by loss of glacier area. This decline in natural glacier storage is one reason KWO is contemplating expanding the reservoir storage of Grimselsee.

Triftgletscher spectacular retreat and lake formation 2000-2008

The Triftgletscher in the Bernese Alps of Switzerland has undergone a swift alteration in the last decade. The Swiss have been the most methodical chroniclers of glacier changes over the last century. The Swiss Glacier Commission faithfully recording the annual terminus change of approximately 100 glaciers. In 2009 81 glaciers retreated, 2 advanced and 5 were stationary. One of the retreating glaciers is the Trift, which after a period of limited retreat from 1955-1995 punctuated by a small advance, began a spectacular retreat in 1998, note the below graph from the Swiss Glacier Commission. The retreat began to expose a new glacier lake at 5700 feet (1750 meters) at its terminus in 2000 and then as observed in photographs by Jürg Alean (Glaciers Online) the lake quickly grew to its full size from 2002 into 2003. The summer of 2003 featured remarkably high melt rates in the Swiss Alps mean losses of more than 2 meters of thickness, and no retained snowpack on two of the three glaciers examined for mass balance. and retreat of 99 of the 100 glacier examined, one was stationary. The lake is now 900 m long. By 2007 the glacier no longer was in contact with the lake, and had by 2008 retreated 180 meters from the lake margin. This is a retreat of 1100 meters since 2000. The lake will shrink as the river outlet from beneath the glacier fills part of the northern end of the lake with glacier sediment.The glacier has a large upper accumulation zone above 9000 feet that retains substantial snowcover (2750 Meters), an upper icefall immediately below this point. The lower icefall descends from 7700 feet (2350) m to 6600 feet (2000 meters). the lower icefall has thinned considerably in the last decade feeding little new ice to the terminus tongue below the icefall the terminus tongue has become stagnant as a result and retreat of this tongue will continue. The story is similar to that of Rotmoosferner Glacier and is driven by the same melt conditions that has led to use of blankets to protect Stubai Glacier.A new suspension bridge has been built to restore access to the glacier that was lost with the rapid retreat.