Findelengletscher, Switzerland Retreat & Hydrology Insights from David Collins

On October 3, 2016May 1, 2024 By mspeltoIn glacier climate change, switzerland glacier retreat

Landsat image comparison of Findelengletscher from 1988 to 2015. Red arrow indicating the 1988 terminus location and yellow arrow the 2015 terminus location. The purple arrows indicate two tributaries connected to the main glacier in 1988 and now disconnected.

Findelengletscher along with Gornergletscher drains the west side of the mountain ridge extending from Lyskamm to Monte Rosa, Cima di Jazzi and Strahlhorn in the Swiss Alps. It is the headwaters of the Matter Vispa. This glacier was also the favorite field location for David Collins, British Glaciologist/Hydrologist from University of Salford who passed away last week. David had a wit, persistence and insight that are worth remembering. This post examines both David’s findings reaching back to the 1970’s gained from a study of glaciers in this basin and changes of the glacier since 1988 as evident in Landsat images. Findelengletscher drains into the Vispa River which supports for hydropower project, with runoff diverted into two hydropower reservoirs, Mattmarksee operated by the Kraftwerke Mattmark producing 650 Gwh annually, and Lac de Dix operated by Grande Dixence that produces 2000 Gwh annually. There are two smaller run of river projects as well.

The Swiss Glacier Monitoring Network has monitored the terminus change of Findelengletscher since the 1890’s. The glacier advanced 225 m from 1979-1986, retreated 450 m from 1988-1999 and retreated 850 m from 1999-2015. This is illustrated above with the red arrow indicating the 1988 terminus location and the yellow arrow the 2015 terminus location. The purple arrows indicate two tributaries connected to the main glacier in 1988 and now disconnected. The more limited retreated from 1988-1999 is evident in images below. The retreat is driven by mass losses with Huss et al (2012) noted as 1 m/year in the alps from 2001-2011. The snowline has typically been above 3250 m too high for equilibrium in the last decade. Melt at the terminus has typically been 7-8 m (WGMS).

Collins (1979) in work funded through hydropower looked at the chemistry of glacier runoff and found that glacier meltwater emerging in the outlet stream was enriched in Calcium, Magnesium and Potassium in particular versus non-glacier runoff, this led to a much higher conductivity. Collins (1982) noted the reduction in streamflow below Gornergletscher from summer streamflow events that reduced ablation for up to a week after the event. Collins (1998) noted that a progressive rise of the transient snow line in summer increases the snow-free area, and hence the area of basin which rapidly responds to rainfall. Rainfall-induced floods are therefore most likely to be largest between mid-August and mid-September and in this period of warmer temperatures and higher snowlines. Collins (2002) Mean electrical conductivity of meltwater in 1998 was reduced by 40%. In the same 60 day period in 1998, however, solute flux was augmented by only 2% by comparison with 1979. Year-to-year climatic variations, reflected in discharge variability, strongly affect solute concentration in glacial meltwaters, but have limited impact on solute flux. Collins (2006) identified that in highly glacier covered basins, over 60%, year-to-year variations in runoff mimic mean May–September air temperature, rising in the warm 1940s, declining in the cool 1970s, and increasing by 50% during the warm dry 1990s/2000s. In basins with between 35–60% glacier cover, flow also increased into the 1980s, but declined through the 1990s/2000s. With less than 2% glacier cover, the pattern of runoff was inverse of temperature and followed precipitation, dipping in the 1940s, rising in the cool-wet late 1960s, and declining into the 1990s/2000s.. On large glaciers melting was enhanced in warm summers but reduction of overall ice area through glacier recession led to runoff in the warmest summer (2003) being lower than the previous peak discharge recorded in the second warmest year 1947. Collins (2008) examined records of discharge of rivers draining Alpine basins with between 0 and ∼70% ice cover, in the upper Aare and Rhône catchments, Switzerland, for the period 1894-2006 together with climatic data for 1866-2006 and found that glacier runoff had peaked in the late 1940s to early 1950s.

These observations have played out further with warming, retreat and more observations. Finger et al (2012) examine the impact of future warming on glacier runoff and hydropower in the region. They observe that total runoff generation for hydropower production will decrease during the 21st century by about one third due glacier retreat. This would result in a decrease in hydropower production after the middle of the 21st century to keep Mattmarksee full under current hydropower production. Farinotti et al (2011) noted that the timing of maximal annual runoff is projected to occur before 2050 in all basins and that the maximum daily discharge date is expected to occur earlier at a rate of ~4 days/decade. Farinotti et al (2016) further wondered if replacing the natural storage of glacier in the Alps could be done with more alpine storage behind dams.

Google Earth image indicating flow of the Findelengletscher.

Landsat image comparison of Findelengletscher from 1999 to 2016. Red arrow indicating the 1988 terminus location and yellow arrow the 2015 terminus location. The purple arrows indicate two tributaries connected to the main glacier in 1988 and now disconnected.

Terminus of Findelengletscher in Google Earth. The lower several hundred meters has limited crevasses, but is not particularly thin.

Vallelunga and Barbadorso Glacier Retreat, South Tyrol Italy

On May 12, 2016May 2, 2024 By mspeltoIn climate change glacier retreat, Italy glacier retreat

Vallelunga (above) and Barbadorso di Dentro Glacier (below) retreat from 2003 (orange line) to 2015 yellow dots. Blue arrows indicate flow path and pink arrow the junction of main two tributaries of Vallelunga Glacier.

Vallelunga Glacier and Barbadorso di Dentro Glacier are at the headwaters of the Vallelunga watershed which feeds the Reschensee. Reschensee is a reservoir famous for the church tower that emerges above its surface. This artificial lake was completed after World War II and is the reservoir for the 105 MW Glurns Hydroproject owned by Seledison. These two glaciers are examined as part of the annual campaign of the Italian Glacier Committee. The annual reports for 2011-2013 indicate a retreat of 78 m for Vallelunga and 60 m for Barbadorso. Here we examine Google Earth images from 2003 and 2015 to indicate the change in a twelve year period.

In 2003 Vallelunga Glacier terminus was at an altitude of 2500 m. The glacier is comprised of two tributaries that join at the pink arrow. The orange line is the 2003 terminus location. By 2015 the smaller western tributary has nearly separated from the main glacier. the terminus has retreated 460 m in the 12 year period. Barbadorso Glacier terminated at 2690 m in 2003. By 2015 the terminus has retreated 250 m and terminates 100 m higher in elevation at nearly 2700 m. On July 31, 2015 the snowline on the two glaciers is at 3100-3200 m with 6-8 weeks left in the melt season. This indicates another year of negative mass balance that will continue to drive retreat.

These glaciers are just across the border from Gespatcherferner one of the fastest retreating Austrian Glacier’s in recent years. Carturan et al (2016) examining long term Italian glacier mass balance series note the 2004-2013 period as particularly negative. They further observe that this is mainly due to increased ablation and that annual balance is becoming more closely correlated with accumulation season (October-May) temperature suggesting warmer winters extending melt season and leading to an increased ratio of winter rain events. The continued reduction in glacier area reduces late summer water flow to the reservoir, which will either cause reduced power output or the need for more storage early in summer (Pelto, 2014).

Vallelunga watershed feeding Reschensee (R). Vallelunga Glacier (V) and Barbadorso Glacier (B).

July 31, 2015 Landsat indicating a high snowline, purple dots, with nearly half the summer to go.

Lex Blanche Glacier Recession, Mont Blanc Massif, Italy

On December 28, 2015May 2, 2024 By mspeltoIn climate change glacier retreat, Glacier Observations, Italy glacier retreat

Lex Blanche Glacier (Lb) comparison in a 1990 and 2015 Landsat image. Red arrow indicates 1990 terminus, yellow arrow the 2015 terminus and the purple arrow a separated tributary. Debris covered Miage Glacier (M) is adjacent.

Lex Blanche Glacier descends from 3500 m on the southeast flank the Aiguille de Glaciers of the Mont Blanc Massif into the Vale Veny of Italy. The glacier is adjacent to Miage Glacier (M). The glacier advanced over 700 m from 1970 to 1990. In 1990 the glacier extended to the base of a steep slope and turned north to terminate at 1980 m. By 2001 the glacier has retreated up a steep slope to near where the 1970’s advance had begun. By 2009 and 2011 further retreat has left the terminus just above a particularly steep bedrock slope. By 2015 the glacier has retreated 1100 m and terminates at 2450 m remaining on a relatively steep slope. The glacier is heavily crevassed a short distance above the terminus suggesting the period of rapid retreat should be ending. A tributary from the north has detached from the main glacier at the purple arrow. In recent warm summers the glacier has retained snowcover above 3150 m. The mass balance noted in Figure 8 (see below) of a paper by Berthier et al (2014) indicates the thinning is glacier wide but most prominent on glacier tongue. Berthier et al (2014) used the Pléiades satellites to identify a negative region wide mass balances of glaciers in the Mont-Blanc area of -1.04 m/year for the 2003-2012 period. The meltwater runoff from this glacier feeds the Dora Baltea River and then the Po River. Both rivers feature extensive hydropower including the Champagne and Nus hydropower plant on the Dora Baltea that produce 41 MW. The retreat of this glacier mirrors that of other glaciers of Mont Blanc including Taconnaz, Bionnassay, Mer de Glace and Tour Glacier.

Figure 8 from Berthier et al (2014) on glacier wide mass change with thinning in browns, and darker browns greater thinning.

Google Earth image from 2001 indicating the 1990 terminus at red arrow and 2001 terminus at yellow arrow.

Google Earth image from 2009 indicating the 1990 terminus at red arrow and 2009 terminus at yellow arrow.

Google Earth image from 2011 indicating the 1990 terminus at red arrow and 2011 terminus at yellow arrow. Blue arrow indicates the lowest heavily crevassed region.