Central Andes Glaciers of Chile and Argentina Nearly Snow Free Again in 2025

**Alto and Baja del Plomo Glacier in false color Sentinel image from 3-17-2025, expanding bedrock areas amidst upper Baja del Plomo Glacier.**

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 (Pelto, 2010). In the Central Andes of Argentina and Chile I have chronicled the near total loss of snowpack, leading to dirty/dark snowcover free glaciers. in 2022 and 2023 (Pelto, 2023). In 2025 this pattern is again apparent. From north of Santiago at Olivares Glaciers and Alta/Baja de Plomo Glacier to east of Santiago at Volcan Overo adn Fiero Glacier to south of the Santiago region at Cobre Glacier and Volcan Peteroa we see glaciers in mid-March with less than 10% snowcover remaining. This is indicative that the 2024/25 mass balance period for the Central Andes will be one of significant loss.

**Olivares Glaciers and Juncal Sur in in false color Sentinel image from 3-17-2025,**

**Volcan Overo Glaciers in false color Sentinel image from 3-17-2025, continued fragmentation and expanded bedrock area amidst glaciers evident.**

**Del Humo and Fiero Glacier in false color Sentinel image from 3-17-2025.**

**CobreaGlacier in false color Sentinel image from 3-17-2025, is retreating both at the top (northwest) and terminus (southeast) of the glacier.**

**Volcan Peteroa Glaciers in false color Sentinel image from 3-17-2025.**

Active Calving Period Northen Patagonia Icefield Revealed in Christmas 2024 image.

On December 27, 2024 By mspeltoIn chile glacier retreat, Glacier Observations

Steffen Glacier calved off the Z group of icebergs at start of December following on a March prodution of X and Y bergs and a December-February 2023/24 breakoff of A,B,C. The Z icebergs have an area of 3 km², **false color Sentinel image.**

Steffen Glacier is the largest south flowing outlet of the 4000 km² Northern Patagonia Icefield (NPI). On December Dec. 6, 2023 the terminus tongue has a narrow unsupported section that appears poised to calve (C). By Dec. 26, 2023 the glacier has calved berg C (0.4km² ), joining other large bergs remaining from previous years D, E and F. Two more pieces A and B appear poised to calve. By Feb. 9 2024 berg B had calved, and by Feb. 24 berg A had calved, together they are 0.3 km². On April 14 two more large bergs X and Y have calved from the terminus. Berg X is the largest of the year at 0.6 km², berg Y is 0.2 km² . Terminus retreat from Dec. 2023-April 2024 is 1.5 km. In noted in April that the terminus tongue was narrow and unsupported (Pelto, 2024) , indicating that more large icebergs should be expected in the 2025 summer season, and in December this happened releasing several icebergs Z1, Z2 and Z3 with a combined area of 3 km² The glacier retreated 2.6 km as a result of this calving event.

**Steffen Glacier in 2024 False Color Sentinel images illustrating calving events yielding bergs A,B,X and Y that have a combined area of 1.5 km².** **Green arrow is Dec. 2023 terminus and yellow arrow April 2024 terminus.**

**Exploradores terminus area on east side collapsing in 2023 and 2024, yellow dots indicate glacier edge, with a melange of bergs beyond** **in this false color Sentinel image.**

Exploradores Glacier is an northern outlet glacier of the Northern Patagonia Icefield. In 2016 Exploradores Glacier had a 12 km² terminus lobe with a couple of small proglacial lakes with a total area of ~1 km². The terminus lobe of the Exploradores Glacier is now collapsing, this is a process that has already occurred at Steffen Glacier, San Quintin Glacier and Colonia Glacier. The terminus lobe is relatively stagnant as indicated by the minimal surface slope. The result will be a new substantial proglacial lake. In 2023 and 2024 an active zone of calving has developed on the east side of the terminus, yellow dots, with an area of 2.1 km². This appears ready to continue expanding west across the glacier tongue expanding this embayment.

**Reichert Glacier in false color Sentinel images illustrationg retreat in 2024 to yellow arrows from pink arrows due to calving that also generated many small icebergs.**

Reichert Glacier is an outlet glacier of the Northern Patagonia Icefied that retreated 6.7 km from 1987-2015. Then was nearly stationary to 2023, with a 750 m retreat from 2022 to 2024 and an active calving period spring 2024 note new icebergs in the lake. The terminus is retreating into a narrower fjord reach,, with a pinch point 1.5 km behind the terminus, that should provide short term stability.

Steffen Glacier, Chile Active Calving Season Concludes with Largest Event in 2024

On April 21, 2024 By mspeltoIn Glacier Observations

Steffen Glacier is the largest south flowing outlet of the 4000 km² Northern Patagonia Icefield (NPI). Several key research papers have reported on the spectacular retreat of this glacier in recent years. Glasser et al (2016) reported that Steffen Glacier proglacial lake area expanded from 12.1 km² to 20.6 km² from 1987 to 2015, due in part to a 100 m snowline rise. Dussaillant et al (2018) determined annual mass loss of NPI at ~-1 m/year for the 2000-2012 period, with Steffen Glacier at -1.2-1.6 m/year. The result Steffen Glacier retreat from 1987-2019 was 4.4 km, ~137 m/year (Pelto, 2019).

On December Dec. 6, 2023 the terminus tongue has a narrow unsupported section that appears poised to calve (C). By Dec. 26, 2023 the glacier has calved berg C (0.4km² ), joining other large bergs remaining from previous years D, E and F. Two more pieces A and B appear poised to calve. By Feb. 9 2024 berg B has calved, and by Feb. 24 berg A has calved, together they are 0.3 km².

On April 14 two more large bergs X and Y have calved from the terminus. Berg X is the largest of the year at 0.6 km², berg Y is 0.2 km² . Terminus retreat from Dec. 2023-April 2024 is 1.5 km. The terminus tongue is again narrow and unsupported as the winter season begins, indicating that more large icebergs should be expected in the 2025 summer season. Millan et al (2019) indicate the area of tributary glacier convergence near the northwest terminus and above the glacier is 700 m thick, and that the glacier has been retreating along an area where the glacier bed is below sea level, though the terminus now is close to sea level.

**Steffen Glacier in Dec. 2023 False Color Sentinel images illustrating calving event yielding berg C.** **Green arrow is Dec. 2023 terminus and yellow arrow April 2024 terminus.**

Tupungato Sur Glacier, Argentina Retreat and Detachment

On April 1, 2024 By mspeltoIn Glacier Observations

Central Andean Glaciers Laid Bare for Last Half of Summer 2022

On April 1, 2022April 20, 2024 By mspeltoIn argentina glacier retreat, chile glacier melt

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

For an alpine glacier to survive it must remain mostly snowcovered throughout the year, even at the end of the summer. This is one reason for the majesty of glaciated mountains, they shine brightly even in summer. This year in the Central Andes of Argentina and Chile I have chronicled the near total loss of snowpack in January due to early summer warmth, leading to dirty/dark glaciers. This is a similar story to what we saw in the Pacific Northwest last summer. Here is an update at the end of the summer using Sentinel imagery to highlight that these glaciers have remained largely bare for two months. The darker 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. Earlier observations indicate this is a regional issue this summer with snowpack lost from Bajo del Plomo Glacier, Cortaderal Glacier, Palomo Glacier, Volcan Overo Glaciers, Volcan San Jose Glaciers , Cobre Glacier and Olivares Beta and Gamma Glaciers across the Central Andes of Chile and Argentina

Cortaderal Glacier in Sentinel image with no retained snowcover this summer, and bedrock expansion at Point A.

Volcan San Jose Glaciers in Sentinel image continues to fragment with ~5% retained snowcover this summer, and bedrock expansion at Point A.

Las Vacas Glaciers in Sentinel image continues to fragment with no retained snowcover this summer, and bedrock expansion at Point A.

Olivares Beta and Gamma Glacier in Sentinel image with no retained snowcover this summer, retreating away from proglacial lakes and bedrock expansion at Point A.

Bajo del Plomo Glacier in Sentinel image with no retained snowcover this summer, and rapid bedrock expansion at Point A.

Palomo Glacier in Sentinel image with no retained snowcover this summer, and bedrock expansion at Point A.

Volcan Peteroa Glacier in Sentinel image continues to fragment with ~2% retained snowcover this summer, and bedrock expansion at Point A.

Tic Toc Glacier, Chile Rapid Losses with Time 1986-2019

On January 25, 2019April 25, 2024 By mspeltoIn chile glacier retreat

Tic Toc Glacier (TT) and Oeste Glacier (O) in 1986 and 2018 Landsat images. Red arrow is the 1986 terminus, yellow arrow is the 2018 terminus location, purple dots the snowline.

Tic Toc Glacier at the headwaters of the Rio Tic Toc and the adjacent Rio Oeste headwater glacier Oeste Glacier are in the Parque Nacionale Corcovado of Palena Province of Chile. Davies and Glasser (2012) noted that overall glaciers in this region lost 14% of their area from 1986 to 2011. Carrivick et al (2016) reported the glaciers in the region had an average thickness of 41 m, this is relatively thin. Here we examine glacier change from 1986 to 2018 using Landsat imagery, with a 2019 Sentinel image for further visual identification of features.

In 1986 Oeste Glacier extended downvalley terminating beyond the east end of a basin, near the west end of an adjacent bedrock knob to its south. The glacier has a 3 km long, 1 km wide valley tongue fed by a higher accumulation zone to the north. Tic Toc Glacier has a terminus tongue that turns from west to north extending 800 m downvalley. This glacier has a larger accumulation zone than Oeste Glacier, the snowline in 1986 is at 1350 m the divide between the glaciers. By 1999 Oeste Glacier has retreated from the bedrock knob and a small fringing lake is developing. Tic Toc Glacier has lost much of the northern terminus tongue. The snowline in 1999 is at 1500 m. By 2016 Oeste Glacier has retreated upvalley revealing a new lake. Tic Toc Glacier has retreated out of the north trending valley that it had terminated in. The divide between the glacier is now mostly bedrock indicating it is consistently above the snowline. The snowline in 206 is above 1500. By 2018 Oeste Glacier has retreated 1700 m losing the majority of its valley tongue. It is poorly connected to the upper snowfield as revealed by both Digital Globe imagery and 2019 Sentinel imagery below, indicating the lack of a substantial contributing accumulation zone. Tic Toc Glacier has retreated 1500 m since 1986, most of its valley length. There is still a significant accumulation zone for this glacier. In both cases the majority of the valley portion of these glaciers has been lost since 1986 and the substantial divide connection has been severed. The large scale loss of these two glaciers is typical for the region as noted by the references above and by the examples of Erasmo Glacier and Hornopiren Glacier.

Tic Toc Glacier (TT) and Oeste Glacier (O) in 1999 and 2016 Landsat images. Red arrow is the 1986 terminus, yellow arrow is the 2018 terminus location, purple dots the snowline and purple arrow the divide.

Digital Glacier image indicating Tic Toc Glacier and Oeste Glacier. Red arrows indicate 1986 terminus locations, far from the current terminus location.

A 2019 Sentinel image of Tic Toc and Oeste Glacier. Red arrow 1986 terminus, yellow arrow 2018 terminus and purple arrows bedrock areas separating Oeste Glacier from the accumulation zone.

Glaciar Olvidado, Chile Retreat Lake Expansion 1985-2017

On January 12, 2018April 28, 2024 By mspeltoIn chile glacier melt, chile glacier retreat

Glaciar Olvidado (O) retreat illustrated in 1985 and 2017 Landsat images. Red arrow is 1985 terminus location, yellow arrow is 2017 terminus location and purple dots are the snowline. This illustrates an 1800 m retreat.

Glaciar Olvidado (G) is a glacier in the southeast portion of the Southern Patagonia Icefield (SPI), adjacent to Grey Glacier (G). The glacier terminates in a proglacial lake. Rivera and Casassa (2004) report the glacier terminating in a newly formed lake in 1986 and retreating slowly from 1986 to 2000. Here we examine changes in the glacier from 1985 to 2017 using Landsat imagery.

In 1985 the glacier terminates in small newly formed proglacial lake that is just 200 m long. The snowline in 1985 is at 1050 m. In 2000 the lake has expanded to a length of 900 m. The snowline in 2000 is at 950 m. By 2016 the proglacial lake has expanded to a length of 2 km. The snowline in 2016 is at 1100 m. In 2017 the glacier has retreated 1800 m since 1986. The snowline is at the base of the steep slopes at 1150 m. The high snowline leaves less than 30% of the glacier in the accumulation zone. The high snowlines indicate a limited accumulation zone, which generates a negative mass balance and drives retreat. The glacier continues to calve into this terminus lake adding to the negative mass balance and consequent retreat. This glacier adds to the growth of proglacial lakes seen in the Northern Patagonia Icefield (Glasser et al 2016) and SPI (Iribarren et al 2014). Olvidado Glacier retreat in terms of distance is similar to the adjacent Grey Glacier, but does represent 20% of its total length. The retreat is much less than the HPS-12 glacier on the west side of the SPI.

Glaciar Olvidado retreat illustrated in 2000 and 2016 Landsat images. Red arrow is 1985 terminus location, yellow arrow is 2017 terminus location and purple dots are the snowline.

Olvidado Glacier in 2016 Google Earth image.

Gabriel Quiroz Glacier, Chile Retreat Forms New Lake

On July 13, 2017April 28, 2024 By mspeltoIn chile glacier melt, chile glacier retreat

Gabriel Quiroz Glacier, Chile in 1987 and 2016 Landsat images illustrates the retreat. Red arrow is 1987 terminus, yellow arrow the 2016 terminus, purple arrow a retreating northern tributary and purpe dots the snowline.

Gabriel Quiroz Glacier is a northern outlet glacier of the Southern Patagonia Icefield that drains into the Rio Pascua. The glacier in 1987 terminated within 250 m of Lago Gabriel Quiroz. Willis et al (2012) observed that between February 2000 and March 2012 that the Southern Patagonia Icefield is rapidly losing volume and that thinning extends even to high elevations. The overall retreat has been driven by increasing calving rates from the 1975-2000 to the 2000-10 period (Schaefer et al, 2015). The pattern of retreat is consistent between these glaciers and the region as noted by Davies and Glasser (2012), annual rates of shrinkage in the Patagonian Andes increased in from 0.10% year from 1870-1986, 0.14% year from 1986-2001, and 0.22% year from 2001-2011, though they note Gabriel Quiroz Glacier retreat rate from 1870-2011 was low. Glasser et al (2016) observed both an increase in glacier proximal lakes and in debris cover on glaciers with glacier retreat from 1987-2015. In this case the glacier is now terminating in a new and expanding proglacial lake, but has limited debris cover.

In 1987 the glacier terminates 250 m beyond the western shore of Lago Gabriel Quiroz there is no sign of a proglacial lake at the terminus. The snowline is at 950 m in 1987, A tributary from the north almost joins the main glacier, purple arrow. In 2000 a small proglacial lake is evident at the terminus, which has retreated 300 m. The snowline is at 950 m. By 2015 a substantial proglacial lake has formed with an island in it. The lake is 1.6 km long, which represents the retreat of the glacier since 1987. The snowline in 2015 is at 1050 m. In 2016 the proglacial lake is filled with icebergs indicating continue calving driven terminus retreat totaling 2.1 km since 1987. The snowline in 2016 is at 950 m. The terminus remains poised for additional calving retreat, though the calving front has narrowed. The upper limit of the lake basin is not evident. The northern tributary has retreated up valley away from the main glacier. This indicates that even without calving the mass balance of the glacier would be negative and there would be retreat. The retreat is similar to that seen at Balmaceda Glacier, Bernardo Glacier and Glacier Onelli.

Gabriel Quiroz Glacier, Chile in 2000 and 2015 Landsat images illustrates the retreat. Red arrow is 1987 terminus, yellow arrow the 2016 terminus, purple arrow a retreating northern tributary and purpe dots the snowline.

Bernal Glacier, Retreating from Chilean Fjord

On April 7, 2017May 1, 2024 By mspeltoIn chile glacier retreat

Bernal Glacier terminus looking towards Estero las Montañas from Eñaut Izagirre and Camilo Rada.

Bernal Glacier drains east from the Sarmiento de Gamboa Range in Southern Patagonia terminating a short distance from the Estero las Montañas. The glacier is in the Alacalufes National Reserve and can be seen from boats traveling up the fjord. Davies and Glasser, (2012) indicate extensive recession of almost all glaciers in the range from 1870-2011. The fastest recession rate of recession of Bernal Glacier is from 2001-2011. Melkonian et al (2013) observed that the Cordillera Darwin Icefield (to the south) had an average thinning rate of −1.5 m w.e/year from 2001-2011, while Willis et a (2012) quantify a rapid volume loss of the Southern Patagonia Icefield (SPI-to the north) from 2000-2012. Incognita Patagonia has been exploring and mapping glaciers in the region since 2015 including a visit to Bernal Glacier in March 2017 that inspired this post Izagirre (2017).

In 1986 there is no proglacial lake evident at the terminus of the glacier, red arrow. By 2013 the glacier has thinned and retreated enough to reveal a pair of proglacial lakes separated by a moraine where the glacier terminated in 1986, red arrow. By 2017 the proglacial lake has further expanded and glacier thinning has revealed larger areas of bedrock at the purple arrows. There is not significant calving in the shallow proglacial lake and the retreat is driven by surface melting. The revegetation of the proglacial outwash areas in 2017 is also apparent. The amount of retreat from 1986 to 2017 is best viewed in the Google Earth image below. The vegetation trimline from the 1980’s is evident. Total retreat from 1986 to 2017 is meters. It is The glacier drains the same ice field as the retreating Dama Blanca Glacier and Balmaceda Glacier.

Landsat comparison of Bernal Glacier in 1986, 2013 and 2017 with the red arrow indicating the 1986 terminus. Purple arrows indicate two areas of bedrock that will be exposed.

Bernal Glacier in Google Earth image from 2015. Red arrow is the 1986 terminus, note the vegetation trimline at that point.

Looking at the Bernal Glacier from the base camp Eñaut Izagirre and Camilo Rada.

Dama Blanca Glacier Retreat, Southern Chile

On April 3, 2017May 1, 2024 By mspeltoIn chile glacier melt, chile glacier retreat, climate change glacier retreat

Dama Blanca Glacier in Landsat images from 1986 and 2017. Red arrow is the 1986 terminus, yellow arrow the 2017 terminus, purple dots the snowline and purple arrows a bedrock ridge.

Dama Blanca Glacier drains west from Chile’s Sarmiento de Gamboa Range in Southern Patagonia. terminating in Lago Verde in the Alacalufes National Reserve. Alacalufes NR features kelp rich fjords, Northofagus coastal forests and glacier clad alpine zones. Davies and Glasser, (2012) indicated extensive recession of almost all glaciers in the range from 1870-2011. They indicate the fastest recession rate of Dama Blanca is from 1986-2001. This range is between the Southern Patagonia Icefield to the north and the Cordillera Darwin Icefield to the south. Incognita Patagonia has been exploring and mapping glaciers in the region since 2015, and have provided a map shown below in coordination with Camilo Rada and Natalia Martinez of the UNCHARTED project . On Marinelli Glacier, in the Cordillera Darwin Icefield, Koppes et al (2009) indicated a retreat of 13 km from 1960 to 2005. More recently Marinellli Glacieri retreated ~3.75 km from 1998 to 2014. Melkonian et al (2013) observed that the Cordillera Darwin Icefield had an average thinning rate of −1.5 m w.e/year with more rapid losses north and west. This is a continuation of the trend noted by Holmund and Fuenzelida (1995) that glaciers on the northern side have a trend of receding fronts. On the southern side the present extent of some glaciers are similar to their 20th century maximum extents. The region is characterized by strong climatic gradients, with high rates of precipitation on the southwestern side of the range where glaciers are faring better and drier conditions on the northern side. Given that the Sarmiento de Gamboa Range is north of Cordillera Darwin it would be expected this area would have substantial recession.

Here we compare satellite images from 1986-2017 to determine the changes of Dama Blanca Glacier. In 1986, the glacier terminated at the end of a peninsula on the south side of Lago Verde, red arrow. The snowline was at 500m. In 2013 the terminus has retreated significantly from the peninsula and the snowline is at 650 m. By 2017 the terminus has retreated 700 m since 1986. The snowline is obscured by clouds in the Landsat image. In February 2017 the snowline is at 700 m. There is also expansion of a bedrock rib on the west side of the glacier that extends to 800 m, purple arrow. The glacier remains actively crevassed to the glacier front as illustrated by the Google Earth image. The glacier will continue to retreat as long as calving continues; however, there is an increase in slope 200-300 m from the current glacier front suggesting the limit for lake development. Izagirre (2017) and the UNCHARTED project explored a number of glaciers in the Sarmiento de Gamboa Range this spring, that will lead to a detailed current map. The retreat here is similar to that of Balmaceda Glacier.

Dama Blanca Glacier in Landsat imags from 2013 and Sentinel image from Dec. 2016 Red arrow is the 1986 terminus, yellow arrow the 2017 terminus, purple dots the snowline and purple arrows a bedrock ridge.

Map from the UNCHARTED Project indicating glaciers of the Sarmiento de Gamboa Range and exploration routes.

Google Earth image of Dama Blanca Glacier in 2013, with the 1986 terminus position at the red arrow.

Erasmo Glacier, Chile Terminus Collapse

On January 17, 2017May 1, 2024 By mspeltoIn chile glacier melt, chile glacier retreat

Erasmo Glacier, Chile, comparison in 1987 and 2016 Landsat images. The red arrow indicates the 2016 terminus and the yellow arrow the 1987 terminus location. Purple dots indicate the snowline and purple arrows locations of upglacier thinning.

Cerro Erasmo at 46 degrees South latitude is a short distance north of the Northern Patagonia Icefield and is host to a number of glaciers the largest of which flow northwest from the mountain. This is referred to as Erasmo Glacier with an area of ~40 square kilometers. Meltwater from this glacier enters Cupquelan Fjord, which is host to farmed salmon. This remote location allows Cooke Aquaculture to protect its farm from environmental contamination. Runoff from Erasmo Glacier is a key input to the fjord, while Rio Exploradores large inflow near the fjord mouth limits inflow from the south. Davies and Glasser (2012) mapped the area of these glaciers and noted a 7% decline in glacier area from 1986-2011 of Cerro Erasmo. The recent retreat of the largest glacier in the Cerro Erasmo massif indicates this area retreat rate has increased since 2011. Paul and Molg (2014) observed a more rapid retreat in general of 25% total area lost from glaciers in the Palena district of northern Patagonia from 1985-2011, a region at 43-44 south, north of Cerro Erasmo.

In 1987 Erasmo Glacier had a land based terminus at the end of a 6 km long low sloped valley tongue. The snowline was at 1100 m. In 1998 there is thinning, but limited retreat and the snowline is at 1250 m. In 2001 a lake has still not formed and retreat is less than 500 m since 1987. By 2013 a proglacial lake has formed and there are numerous icebergs visible in the lake. The snowline is at 1200-1250 m in 2013 at the top of the main icefall. In 2015 a large lake has formed and the snowline is at 1200 m again at the top of the icefall. By 2016 the terminus has retreated 2.9 km since 1987 generating a lake of the same length. The collapse is ongoing as indicated by large icebergs in the lake. The snowline in 2016 is at 1200 m at the top of the icefall The purple arrows indicate locations of expanded bedrock amidst the glacier since 1987. Each location is above 1000 m indicating upglacier thinning and reduced retained snow accumulation is driving the retreat. The west most purple arrow indicates where a glacier formerly was joined to the Erasmo Glacier and is now separated. The retreat is consistent with retreat documented at Reichert Glacier, Hornopirén Glacier and Cord.illera Lago General Carrera Glacier. The rapid retreat will continue until the head of the developing lake basin is reached.

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Hornopirén Glaciers, Chile in Spectacular Retreat

On November 28, 2016May 1, 2024 By mspeltoIn chile glacier melt, chile glacier retreat

Landsat comparison of Rio Blanca Glaciers in Hornopirén National Park, Chile from 1985 to 2016. Red arrow 1985 terminus, yellow arrow 2016 terminus, purple dots the snowline and purple arrows expanding bedrock areas amidst the glacier.

Hornopirén National Park is in the Los Lagos region of Chile. The park is host to a number of glaciers that are in rapid retreat. Davies and Glasser (2012) mapped the area of these glaciers with 113 square kilometers in 1986 and 96 square kilometers in 2011. The retreat of the largest glaciers in the park is nothing short of spectacular in recent years. Here we examine Landsat imagery to identify changes in two or the larger valley glaciers from 1985-2016. These glaciers from the headwaters of the Rio Blanco and are designated Rio Blanco North (RBN) and Rio Blanco South (RBS). Rio Blanco enters the ocean just east of the community of Hornopirén.

In 1985 the two glaciers merged just before the western terminus of the icefield at 820 m, red arrow. The snowline was at 1300 m. There is also an eastern outlet of RBN, terminating at the north end of a basin, red arrow. By 1998 RBN and RBS had separated by over 1 km with the formation of a new lake at the former terminus. The eastern terminus of RBN has begun retreat and is now ending in a proglacial lake. RBS is developing a nunatak at the purple arrow. The snowline was again near 1300 m. By 2016 RBN has retreated 4.5 km, and now terminates at 1200 m, yellow arrow. The deglaciated valley now hosts three alpine lakes that did not exist in 1985. The eastern terminus of RBN has retreated 1100 m and is still terminating in an expanding alpine lake, yellow arrow. By 2016 RBS had retreated 3.4 km since 1985, terminating at 1180 m, yellow arrow. The nunatak in the lower section of RBS, purple arrow, has continued to expand. RBN has lost 56% of its length since 1985 and RBS 37% of its length.The snowline in 2015 and 2016 is at 1600-1700 m. This leaves only a small percentage of the glacier area above the snowline. The large valley glaciers that just 30 years dominated the headwaters of Rio Blanco have lost much or their area and will soon be small slope glaciers clinging to the highest peaks. Retreat here is more extensive than seen 100 km to the northwest at Calbuco Volcano and for the Northern Patagonia Icefield.

Landsat comparison of Rio Blanca Glaciers in Hornopirén National Park, CVhile from 1998 to 2015. Red arrow 1985 terminus, purple dots the snowline and purple arrows expanding bedrock areas amidst the glacier.