Cortaderal glacier retreat – From a Glaciers Perspective

Bajo del Plomo Glacier, Argentina in Sentinel image with no retained snowcover this summer, and rapid bedrock expansion at Point A-C. This is 2nd consecutive year without retained snowcover for this glacier at the head of the Rio Plomo.

For an alpine glacier to thrive it must remain 50-60% snowcovered throughout the year, even at the end of the summer. To survive it must have consistent significant snowcover at the end of summer, indicative of a persistent accumulation zone. This year in the Central Andes of Argentina and Chile I have chronicled the near total loss of snowpack through February, leading to dirty/dark snowcover free glaciers. This is a same story we observed in 2022, though snowcover was lost in January last year (Pelto, 2022). The consecutive summers with glaciers laid bare results in significant losses. The darker bare surfaces of the glacier melt faster leading to more rapid area and volume loss. This includes fragmentation and rapid expansion of bedrock areas amidst the glacier. We saw in the Pacific Northwest two consecutive summers with limited snowcover retained. Hopefully the Central Andes region will experience a good winter much as the Mount Shasta, CA area has in winter 2023.

Here is an update at the end of the summer using false color Sentinel imagery to highlight a sample of these glaciers that have remained largely bare for two months. Individual posts during 2022 or 2023 include: Volcan Peteroa glaciers, Rio Atuel glaciers, Sollipulli Glacier, Palomo-Cipreses Glacier, Bajo del Plomo Glacier, Cortaderal Glacier, Volcan San Jose Glaciers , Cobre Glacier, Olivares Beta and Gamma Glaciers and Volcan Overo Glaciers,

Olivares Beta and Gamma Glacier, Chile in Sentinel image with no retained snowcover this summer, retreating away from proglacial lakes and bedrock expansion. This is 2nd consecutive year without retained snowcover for these glaciers.

Nevado Piquenes, Argentina has less than 5% snowcover retained in this Sentinel image, right near the 6000+ m summit.

Bello and Yeso Glacier, Chile have no trace of snowcover for 2nd consecutive summer. The dirtier surface is leading to faster melt.

El Morado Glacier, Chile has no trace of snowcover for 2nd consecutive summer. The dirtier surface is leading to faster melt, and fragmenting.

Volcan San Jose Glaciers in Sentinel image continues to fragment with a 2nd consecutive year without retained snowcove.

Cortaderal Glacier, Chile in Sentinel image with no retained snowcover this summer, leading to terminus tongue loss at Point A.

Corto, Fiero and Humo Glacier, Argentina with no retained snowcover in 2023, for 2nd consecutive summer. These glaciers feed the Rio Atuel, and their rapid retreat will lead to less summer glacier runoff.

Volcan Overo in Sentinel image continues to fragment with no retained snowcover this summer, and bedrock expansion causing fragementation at Point A, B and C.

Tinguiririca Glacier, Chile drains into the river of the same name. In 2023 this fragmenting glacier lost all its snowcover for 2nd consecutive summer.

Cobre Glacier, Argentina lost all its snowcover in 2023, just like 2022. Here it has separated at Point B and nearly so at Point A.

Volcan Peteroa Glacier, Chile/Argentina border in Sentinel image continues to fragment at Point A with no retained snowcover, this is also leading to lake expansion at Point B.

Map of Central Andes indicating glacier locations from 33-36° S that we focus on here.

Cortaderal Glacier in Landsat images from 2014 and 2022. The glacier retreated 1400 m during this interval. The snowline in January 2014 is at 3750 m. On January 15, 2022 the snowline averages 4100 m with less than 15% snowcovered with 2.5 months left in the melt season. Red arrow is 2014 terminus and yellow arrow is 2022 terminus.

Cortaderal Glacier is a large valley glacier in Central Andes of Chile. Adjacent to the Universidad Glacier, it flows from Volcan Paloma (4860 m) and Nevado Penitente (4350 m) and drains into the Rio Cortaderal. Rio Cortaderal joins the Cachapoal River, that supplies two Pacific Hydro projects; a 110 MW run of river project at Chacayes and the 78 MW Coya run of river project a short distance downstream. The glacier is an important water resource from December-March. Bravo et al (2017) noted for Universidad Glacier that it supplied 10-13% of all runoff to the Tinguirica Basin during the melt season. La Quesne et al (2009) reported that Cortaderal Glacier retreated 110 m from 1970-2000 and 450 m from 2000-2007. Here we examine the retreat of this glacier from 2014-2022 and the unusually high snow lines in mid-January of 2022 due to the recent January heat wave (Washington Post, 2022).

Cortaderal Glacier in Sentinel images from 2016 and 2022. Point A is the bedrock area that emerged in 2016 and was at the glacier front by 2022. Point T marks the 2016 terminus position, Point B is at 3750 m and Point C is at 4200 m. Snowline on January 22, 2016 is at 3200 m and averages 4100 m on January 13, 2022.

In February of 2014 the glacier terminated on the outwash plain at 2800 m. The snowline in mid January was at 3750 m. On January 9, 2016 the snowline was at 3200 m. At Point A a small bedrock area has emerged from beneath the ice 1 km upglacier of the terminus. On January 16, 2017 the snowline is at 3750 m. On January 19, 2019 the snowline is at 3700 m. The bedrock exposed at Point A is no longer surrounded by ice due to expansion and glacier retreat. On December 14th the snowline is at 3700 m and the glacier is 50% snowcovered. By January 15 there is less than 15 % snowcover, and the snowline averages 4100 m, nearly at the top of the glacier. With 10 weeks left in the melt season snowcover will decline further. This is reminiscent of reduced snowcover on glaciers in the Pacific Northwest due to the summer 2021 heat wave (Pelto, 2021).

The glacier has retreated to Point A, with an average frontal recession of 1300 m from 2014-2022. This is greater than the retreat from 1990-2014 of ~800-900 m (Pelto, 2014). The glacier now terminates at 3050 m in a region of much steeper slope that will reduce the retreat rate in the near future.

Cortaderal Glacier snow covered area change in two Landsat images one month apart. Snowcover declined from ~50% to 15%.

Cortaderal Glacier in Sentinel images from 2017 and 2019. Point A is the bedrock area that emerged in 2016 and was at the glacier front by 2022. Point T marks the 2016 terminus position, Point B is at 3750 m and Point C is at 4200 m. Snowline on January 16, 2017 is at 3750 m and averages 3700 m on January 19, 2019.