Tag: Switzerland glacier mass balance

Breney Glacier Switzerland Accelerating Retreat 1988-2018

On By mspeltoIn switzerland glacier retreat

Breney Galcier, Switzerland in Landsat images from 1988 and 2018.  Red arrow = 1988 terminus location, yellow terminus =2018 and purple dots the snowline.  B=Breney Glacier, G=Gietro Glacier, L=Lateral Moraine, M=Lac Mauvoisin and O=Otemma Glacier.

Breney Glacier (B) is in the next valley to the north of Otemma Glacier (O) and south of Gietro Glacier (G), it  flows southwest into Lac de Mauvoisin (M). Breney Glacier is one of the glaciers where the terminus is monitored annually by the Swiss Glacier Monitoring Network (GLAMOS:VAW/ETH). Here we examine changes in this glacier from 1988 to 2018 including changes in the terminus using Landsat Imagery.  GLAMOS:VAW/ETH reports that Breney Glacier retreated 175 m from 1988-1999, and a further 625 m from 1999-2015.   The Mauvoisin Dam can produce 363 MW of power, and typically provides 1030 millionKWh of power each year. The reservoir can store 200 million cubic meters of water.

Here we examine Landsat images to identify changes in this glacier during the last three decades 1988-2018.  In 1988 the glacier extended onto an outwash plain at 2600 m and the snowline was at 3300 m.  In 1999 the snowline is at 3200 m, the terminus has experienced limited retreat across the low slope outwash plain.  By 2015 the terminus has retreated to ~2700 m, the snowline is at 3500 m.  In 2018 the snowline is at 3500-3600 m too high to sustain the glacier at its current length.  The glacier has retreated from the outwash plain that is still accumulating sediment.  There is significant retreat from 2015 to 2018, more than 100 m. There are regions of ice cored moraine (ICM).  The current lateral moraine that is visible on both margins of the glacier illustrates the recent rapid thinning and the insulating effect of the debris.  There is limited crevassing on the lower glacier which is dissected by a supraglacial stream, note detailed Google Earth image below. The northern arm of Breney is Serpentine Glacier, which is thinning and appears close to separation from Breney Glacier. The retreat is similar in magnitude to adjacent Otemma Glacier (O) and south of Gietro Glacier (G), all driven by high glacier melt and the resulting high snowlines.  The mass balance of Swiss Glaciers has had a sustained strongly negative trend since 2003 (Huss et al 2015).

Breney Galcier, Switzerland in Landsat images from 1988 and 2018.  Red arrow = 1988 terminus location, yellow terminus =2018 and purple dots the snowline. 

Google Earth image from 2016 of the terminus area of Breney Glacier. K=Kettle, OP=Outwash Plain, T=Terminus, S=Supraglacial stream, ICM=ice cored moraine.

Basodino Glacier, Switzerland Mass Balance Loss & Hydropower

On By mspeltoIn switzerland glacier retreat

Basodino Glacier in August and September of 2016 illustrating the upward shift of the snowline in the 15 days between the Landsat (left) and Sentinel (right) image. purple dots mark snowline. 

Basodino Glacier is a small northeast facing slope glacier in the southern Swiss Alps.  The glacier is in the Ticino River watershed and supplies the Robiei Hydropower system. The glacier is in the same basin as Cavagnoli Glacier, which is fading away. The main branch presently covers an area of 1.8 km2 and extends from 2562 to 3186 m.  In 1973 the glacier had an area of 2.3 km2 .  Detailed mass balance investigations have been carried out since 1990.  During this period the glacier has lost more than 11 m w.e. thickness.  In seven years from 1980-2014 the glacier has had an AAR below 10 (Bauder, 2016).  This is indicative of minimal retained accumulation and not a consistent accumulation zone (Pelto, 2010) .  Huss (2012) noted that mean glacier mass balance in the European Alps was −0.31  m w.e./ year from 1900–2011, and −1 m w.e. /year over the last decade.  For Basodino Glacier the loss during this enite period averaged ~-0.2 m w.e./year (Huss, 2012).  The glacier advanced 95 m from 1967-1986 and has retreated 260 m since, front observations are completed and submitted by Claudio Vallegia of Ticino, Sezione Forestale (Swiss-ETHZ, 2016).

Water from glacier melt  is channelled to the Robiei-Zött reservoirs and hydro plants, generating enough electricity for a city. The Cavagnoli and Naret reservoirs at 2310 m feed the Robiei power station, situated 400 m below. The Robiei power station is also capable of pumping the water from the Robiei-Zött up to the higher Cavagnoli-Naret reservoirs.

Basodino Glacier in late August of 2016 had 5-60% of the glacier still in the accumulation zone. two weeks later on Sept. 9, 2016 the glacier had 35% of the glacier in the accumulation zone.  This is the accumulation area ratio, which needs to be above 55% for equilibrium.  For Basodino Galcier 2016 will be another year of mass balance loss and retreat.  The detailed monitoring will provide specific values for each reporting to the Swiss Glacier Monitoring Network system and the WGMS.

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