Category: chile glacier retreat

Steffen Glacier, Chile Drainage of Laguna de Los Tempanos

On By mspeltoIn chile glacier melt, chile glacier retreat

Laguna de los Tempanos full on February 9, 2021 and drained on December 6, 2021 in Sentinel 2 images. Point A marks the western margin when full. Point C marks the western margin when drained. 

Steffen Glacier is the south flowing glacier from 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 tin part to a 100 m snowline rise. noted to have risen ~100 m.  Dussaillant et al (2018) determined the annual mass loss of NPI at ~-1 m/year for the 2000-2012 period, with Steffen Glacier at -1.2-1.6 m/year. 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 retreat from 1987-2019 was 4.4 km, ~137 m/year (Pelto, 2019). Aniya et al (2020) reported on 19 glacier drainage events from 1974-2020, with most occurring in late summer or early Fall. They noted the largest in 2016 and 2017 were the first to expose much of the lake bottom.

There are two large ice dammed proglacial lakes on the west side of the glacier.  Laguna de Los Tempanos is the southern one 6 km upglacier of the current terminus and 11 km upglacier of the 1987 terminus position. Here we utilize Landsat and Sentinel imagery to examine the evolution of the lake from 1987-2021, Including the 2021 drainage event.

Laguna de los Tempanos in Landsat images from 1987, 1999, 2012 and 2019. Yellow arrow is western extent of the lake in 1987 and 1999, while Point A is the western extent in 2012 and 2019.

In 1987 the area of the lake is 5.2 km2 extending west past point A to the yellow arrow. In 1999 the water level is lower leading to a peninsula developing at Point A, with a lake area of 5.0 km2.  By 2012 the water level had dropped further and the west margin of the lake was now at Point A and the lake area was 4.8 km2.  The filled size remained unchanged for most of the 2012-2021 period, though there was large drainage events in 2016 and 2017 the lake rapidly refilled.

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On November 17, 2016 the lake is full, but it is drained on April 16, 2017 with evident icebergs on the bottom, the drainage event occurred on March 30/31 2017 (Aniya et al 2020) . 

By January 21, 2018 the lake is again full and is full again on December 7, 2018 in Sentinel 2 images.

The lake is full on March 27, 2019 and on Feb. 20, 2020 in Sentinel 2 images.

 

On March 31, 2021 the lake is still full, by November 16, the lake area had declined from 4.5 km2 to 1.9 km2, in Sentinel 2 images.

The drainage event appears to have been in the early spring as the lake is full on May 20, 2021 at the start of the winter season and at the end of the winter season on August 8, 2021 in Sentinel 2 images. The lake remained largely filled on Sept. 7, 2021, but had drained by Oct. 7, 2021.

By October 7, 2021 the  lake had drained and two months later the lake is still not filling.  As Steffen Glacier thins, its ability to impound this lake has diminished from 1987 to 1999, from 1999 to 2012 it diminished again.   Now we may have another evolution in this process, with the more complete drainage starting in 2016 and now in 2021 the first event where refilling is not progressing.

Bernardo Glacier, Chile Retreat Yields 15 km2 Lake Expansion 1986-2021

On By mspeltoIn chile glacier melt, chile glacier retreat1 Comment

Bernardo Glacier in Landsat images from 1986 and 2021 illustrating retreat at the southern (S), middle (M) and northern (N) terminus respectively. Red arrows are 1986 terminus locations, yellow arrows are 2021 terminus locations. Separation from Tempano occurs at S, while lake expansion occurs at M and N.

Bernardo Glacier is an outlet glacier on the west side of the Southern Patagonia Icefield (SPI) that  currently ends in an expanding proglacial lake system, with three primary termini.  Here we examine changes from 1986 to 2021 using Landsat images. Davies and Glasser (2012) indicate that over the last century the most rapid retreat was from 2000 to 2011. Willis et a (2012)  note a thinning rate of 3.4 meters per year during this period of the Bernardo Glacier region, which drives the retreat. Mouginot and Rignot (2014) illustrate that velocity remains above 200 m/year from the terminus to the accumulation zone on Bernardo Glacier. Eñaut Izagirre visited the glacier in 2019 and provided images of the middle terminus of Bernardo Glacier, below.

Bernardo Glacier in Landsat images from 1998 and 2020 illustrating retreat at the southern (S), middle (M) and northern (N) terminus respectively. Red arrows are 1986 terminus locations, yellow arrows are 2021 terminus locations. Separation from Tempano occurs at S, while lake expansion occurs at M and N.

In 1986 Bernardo the southern terminus of the glacier was in tenuous contact with Tempano Glacier.  The middle terminus primarily ended on an outwash plain with a fringing proglacial lake developing.  The northern terminus had retreated a short distance south from a peninsula that had acted as a pinning point.  By 1998 the northern terminus had retreated into the wider,deeper portion of the lake basin that was now filled with icebergs. The middle terminus remained grounded on an outwash plain, with proglacial lake expansion at the NW corner of the terminus.  A small lake has developed completely separating Bernardo Glacier and Tempano Glacier. By 2003 the northern terminus had retreated 2 km from 1986, the middle terminus 1.5 km and the southern terminus 1.2 km in an expanding proglacial lake.  By 2015 the lake between Tempano and Bernardo Glacier had drained, but a fringing proglacial lake at the margin of Bernardo Glacier was forming.  In 2015 the northern terminus had retreated 3.5 km since 1986, the middle terminus 2.5 km and the southern terminus 2.75 km.   From 2015 to 2020 the change of the southern terminus was limited to a limited expansion of the fringing proglacial lake, a limited retreat of the the northern terminus, while the middle terminus had retreated significantly into a wider portion of the lake basin.  By 2021 the southern terminus had retreated 3 km since 1986, the middle terminus 4.6 km and the norther terminus 4.1 km.  This led to a 8.7 km2 lake expansion at the middle terminus and a 7.8 km2 lake expansion at the northern terminus. Gourlet et al (2016) identify Bernardo Glacier as having thinner ice than other large outlet glaciers such Jorge Montt or O’Higgins, which helps lead to rapid terminus change. The retreat is similar to the extensive retreat observed at Dickson Glacier and Upsala Glacier.

Southern Andean huemel an endemic deer on the foreland beyond Bernardo Glacier (photograph from Eñaut Izagirre).

Middle terminus of Bernardo Glacier in 2019 taken by Eñaut Izagirre who considers this a condor-view.

Bernardo Glacier in Landsat images from 2003 and 2015 illustrating retreat at the southern (S), middle (M) and northern (N) terminus respectively. Lake expansion and then drainage occurs at S. Red arrows are 1986 terminus locations, yellow arrows are 2021 terminus locations.

Melt Severs Northern Patagonia Icefield Glacier Connections

On By mspeltoIn chile glacier retreat

Loss of glacier connection between HPN1 and HPN2 in Landsat images from 2000 and 202o at Point A and B. Glacier tongue retreat at Point A from HPN1 and at Point C from HPN2. Formation of 1.4 km2 lake at HPN1.

HPN1, HPN2 and HPN3 drain adjacent sections of the the Northern Patagonia Icefield (NPI).  HPN2 and HPN3 comprise the Acodado Glacier, with HPN1 being the next glacier to the north is. The lakes at the terminus of HPN2 and HPN3 were first observed in 1976 and had an area of 2.4 and 5.0 km2 in 2011, while HPN1 had no lake in 2000 (Loriaux and Casassa, 2013).   Davies and Glasser (2012) noted that the Acodado Glacier termini, HPN2 and HPN3, had retreated at a steadily increasing rate from 1870 to 2011. Pelto, 2017 reported a retreat from 1987-2015 of 2100 m for HPN2 and 3200 m for HPN3. From 1987-2020 Acodado Glacier terminus HPN2 has retreated 2700 m and HPN3 has retreated 4100 m.  The result of this retreat is an increase in lake area at HPN2 from 2.1 km2 in 1987 to 7.1 km2 in 2020 (Pelto, 2020). Glasser et al (2016) identified a 40% increase in lake area for the NPI from 1987-2015,  and a 100 m rise in the snowline.  Dussailant et al (2018) identified a mass loss rate of -2–2.4 m/year for HPN1, with thinning of over 4 m/year in the lower reaches in the vicinity of Point A and B. Here we examine the impact of the rising snowline, increased melt and resultant thinning on two glacier tongues that connected HPN1 to the accumulation zone region of HPN2 in 2000 and are now disconnected.

In the 2000 Landsat image glacier tongues extending from the accumulation zone region of HPN2 connect with HPN1 at Point A and Point B. At Point C an ice tongue extends 2.7 km upvalley from HPN2. By 2016 there is a disconnection at Point A with ice flowing south from HPN1 no longer joining the north flowing tongue.  Point B is still connected. At Point C the ice tongue extends 1.8 km upvalley.  By 2020 the connection at Point B has also been severed. At Point A ice no longer flows south into the valley from HPN1 and there is a 3.25 km long deglaciated valley between the two formerly connected ice tongues. At Point C the ice tongue from HPN2 has also been lost, a 2.7 km retreat.  From 2000-2021 HPN1 has retreated 1.8 km leading to the formation of a 1.4 km2 lake. We can anticipate the rapid retreat of the glacier tongue from HPN1 at Point B during this decade.  There is potential of short term formation of glacier dammed lakes at Point A and C now, and Point B in the future.  There is not a hazard from drainage of these lakes that both reach tidewater via Rio Acodado within 15 km.

Loss of glacier connection between HPN1 and HPN2 in Landsat images from 2016 and 2021 at Point B. Glacier tongue retreat at Point A from HPN1 and at Point C from HPN2. Expansion of 1.4 km2 lake at HPN1.

HPN1 in Sentinel 2 image from Nov. 9, 2021 illustrating the 1.4 km2 lake at HPN1 that has formed this century and the deglaciated valley at Point A.

Queulat Glacer Complex, Chile Recession 1987-2021

On By mspeltoIn chile glacier melt, chile glacier retreat

Seven outlet glaciers of the Queulat glacier complex, Chile in 1987 and 2020 Landsat images. A=Rosselot Glacier and D=Colgante Hanging Glacier are the only ones in 1987 not terminating in a proglacial lake. The other five retreated from a proglacial lake since 1987 and Rosselot Glacier retreat has led to formation of two lakes. 

Nevado Queulat, Chile is the centerpiece of the Queulat National Park in the Aysen Region.  This massif is host to the Queulat glacier complex, which has a number of outlet glaciers. Rosselot Glacier is the largest glacier and it flows north draining into Lago Rosselot and then the Rio Palena. Colgante Hanging Glacier flows south and is the second largest terminating at the top of a cliff  as a hanging terminus creating a spectacular waterfall.  Paul and Molg (2014) observed a rapid retreat in general of 25% total area lost from glaciers in the Palena district of northern Patagonia from 1985-2011. Meier et al (2018) note a 48% reduction in glacier area in the Cerro Erasmo and Cerro Hudson region, since 1870 with half of that occurring since 1986. The 3.8 km retreat of Erasmo Glacier from 1998 to 2018 is a rate of ~200 m/year.   Here we examined the changes from 1987 to 2021 of seven outlet glacier locations around the ice cap.

Seven outlet glaciers of the Queulat glacier complex in Queulat National Park in Chile in 2021 Sentinel 2 image. A=Rosselot Glacier and D=Colgante Hanging Glacier are the only ones in 1987 not terminating in a proglacial lake. The other five retreated from the proglacial lake since 1987 and Rosselot Glacier retreat has led to formation of two lakes. 

In 1987 Rosselot (A) terminates against the valley where the valley turns to the east,and there is no lake at the terminus.  In 1999 glacier retreat has exposed a new lake that is 900 m across.  By 2015 the glacier has retreated south of a second lake that is 700 m across.  In 2021 the glacier has retreated 250 m from the edge of the lake terminating at an elevation of 650 m. The total retreat from 1987-2021 has been 2100 m, ~60 m per year.  This is the loss of  15% of the entire glacier length.

Seven outlet glaciers of the Queulat glacier complex, Chile in 1999 and 2015 Landsat images.

Outlet Glacier B terminates in a lake at 750 m.  In 1999 the glacier has retreated to the top of a steep slope above the lake terminating at 850 m.  In 2015 the glacier is terminating at 925 m and is receding up a north-south oriented valley. By 2021 the glacier has retreated 1100 m from the shore of the lake.

Outlet Glacier C terminates in a small fringing proglacial lake.  By 1999 the glacier has retreated ~400 m to the base of a steeper slope, there is still ice cored moraine beyond the terminus. By 2015 a 500 m lake has formed beyond the terminus.  In 2021 the glacier has retreated ~1000 m since 1987.

Colgante Hanging Glacier (D) terminates at the top of a steep cliff in 1987.  The glacier reamins at the top of this cliff up to 2021, with considerable avalanching off the front into the valley below.  A reconstituted glacier at the bottom of the cliff is thinning.

Outlet Glacier (E) terminated in a proglacial lake  at 700 m elevation in 1987.  By 1999 the glacier had a tenuous connection to the lake with a reconstituted stagnant area in contact with the lake. In 2015 the glacier no longer reaches the lake. In 2021 the terminus of the glacier is 400 m from the lake.

Outlet Glacier (F) terminated in a proglacial lake at 750 m elevation in 1987.  In 1999 the glacier still connected to the lake. By 2015 the glacier had receded from this lake. In 2021 the glacier has retreated 350 m from the lake and terminates at  1000 m.

Outlet Glacier G is a stagnant debris covered glacier tongue that is in contact with a proglacial lake in 1987 and 1999.  By 2015 the glacier has retreated from contact with the lake.  In 2021 the glacier has retreated 600 m across an outwash plain from the lake.

Barcaza et al (2017) indicate that Colgante Hanging Glacier did not retreat from 2000-2015, while Rosselot Glacier lost 0.9 km2.

Benito Glacier, Chile 2021 Calving Event Drives Further Retreat

On By mspeltoIn chile glacier retreat, climate change glacier retreat, glacier climate change

 

Benito Glacier in 2000 and 2021 Landsat images. Locations 1-6 are current or former distributary terminus locations. Red arrow is the 2000 terminus location and yellow arrow the 2021 terminus location.  A small cloud is obscuring an iceberg near terminus.  Purple dots are the snowline.

Benito Glacier is a temperate outlet glacier on the west side of the North Patagonian Icefield terminating in an expanding lake. The glacier is south of  San Quintin Glacier and north of Acodado Glacier. Loriaux and Casassa (2013) examined the expansion of lakes of the Northern Patagonia Ice Cap. From 1945 to 2011 lake area expanded 65%, 66 square kilometers. Ryan et al (2018) identified thinning of 2.8 m/year in the ablation zone from 2000-2013, and that thinning of over 120 m extended from the terminus to ~750 m from 1973-2017. Mouginot and Rignot (2015)  indicate that the velocity of Benito Glacier is between 200-500 m per year along the center line below the snowline. Glasser et al (2016) note the glacier has limited debris cover and that the average transient snowline in 2013-2016 is at 1000 m, substantially above the ~900 m average from earlier.

Benito Glacier in 1987 main terminus was on an outwash plain.  The glacier has five distributary termini (1,2,34,5,6) two of which had open proglacial lakes in 1987.  At Point 3 the glacier flows around a nunatak and reconnects. In 2000 a 1 km long proglacial has formed at the main terminus.  Distributary termini 1,2 and 4 all have proglacial lakes.  The snowline in 1987 and 2000 is 800-825 m. By 2015 there are  five ending in lakes, with Lake 6 having retreated out of a lake basin. A lake has formed at the new distributary terminus at Lake 3. The two tributaries to the north indicated with arrows each retreat approximately 1 km from 1987 to 2015 and in both cases are no longer calving termini.  The main glacier terminus has retreated into a proglacial lake, with a retreat of 2 km from 1987 to 2015. The lowest 1.5 km  has a low slope and peripheral lakes suggesting the lake will expand substantially as Benito Glacier retreat continues. The transient snowline in 2015 is at  900 m. In 2021 a significant iceberg 0.4 km2 has calved off the terminus.  The terminus has retreated 2900 m from 1987-2021 with the lake area expanding to 2.8 km2.  The lower 1.5 km of the glacier remains low sloped suggesting significant lake expansion is ongoing. The glacier no longer reaches the former proglacial lake 2 or 6. Proglacial lake 1 has drained. Proglacial lake 2,3, and 4 continue to expand. The snowline on Feb. 6 2021 is at 875-900 m, rising to 925-950 m by March 16, 2021.

March 17, 2021 Landsat image indicating iceberg located off front of Benito Glacier

 

Benito Glacier comparison in Landsat images from 1987 and 2015 indicating the terminus position in 1987 red arrows, yellow arrows the 2015 terminus positions. Locations 1-6 are current or former distributary terminus locations. purple arrows where glacier thinning is expanding bedrock areas. The snowline is indicated by purple dots

Gorra de Nieve East Glacier, Chile Retreat-Lake Expansion

On By mspeltoIn chile glacier retreat

Gorra de Nieve East Glacier in 1986 and 2021 Landsat images. Red arrow is the 1986 terminus location, yellow arrow is the 2021 terminus location, orange arrows the three main tributaries.

The Gorra de Nieve massif is 50 km southwest of Monte San Lorenzo, draining its eastern flank the largest glacier of this massif is unnamed and referred to here as Gorra de Nieve East Glacier. The glacier consists of three main tributaries that join shortly above the proglacial lake the glacier has terminated in, which drains into the Rio Bravo. In this region glaciers thinned by ~0.5 m/year from 2000-2012 with most of the thinning on  Gorra de Nieve East Glacier occurring on the lower sloped valley section below 1100 m (Falaschi et al 2017). The glacial history of the region is detailed in a visual map that includes moraines and trimlines including around the expanding proglacial lake discussed here Davies et al (2020).  Here we examine the changes of the glacier and the expanding proglacial lake from 1986 to 2020.

In 1986 the glacier terminated in a 3 km long proglacial lake, red arrow.  Three primary tributaries joined ~2 km above the terminus at 900 m, orange arrows. By 2003 the glacier has retreated ~500 m and the lateral moraines have become more prominent covering a majority of the glacier width.  By 2016 the glacier has retreated ~900 m from the 1986 position and lateral moraine debris covers nearly the entire lower 1 km of the glacier.  In 2021 the tributaries are separating with the northern tributary the only one feeding the terminus. The glacier has retreated 1500 m since 1986 and the proglacial lake is 4.5 km long.  The two southern tributaries will separate soon and the northern tributary will also retreat from the lake.

The retreat is similar to that  at San Lorenzo Sur Glacier or Calluqeuo Glacier.

Gorra de Nieve East Glacier in 2003 and 2016 Landsat images. Red arrow is the 1986 terminus location, yellow arrow is the 2021 terminus location, orange arrows the three main tributaries.

HPN4 Glacier, Chile New Lake Forms and Drains in 2021

On By mspeltoIn chile glacier melt, chile glacier retreat

Glacier dammed lake formation at HPN4 Glacier, Chile between Landsat images of Feb. 2020 and Feb. 2021, yellow arrows indicating new calving fronts on either end of lake. 

HPN4 Glacier drains the southern side of NPI just east of Steffen Glacier. The terminus retreated little from 1987-2015, see below (Pelto, 2015 and 2017). The main change is in the eastern tributary 1-2 km north of the terminus. In 1987 there were five separate feeder ice tongues descending from the ice cap into this valley.  By 2015 there was just one.  Further this tongue has narrow and downwasted and a new lake is developing.

In February 2020 the lake has still not formed, note yellow arrows. In February 2021 the lake has formed between the yellow arrows and is 2 km long and has an area of 1.1 km2. The drainage of this lake was reported by on Claudio Bravo Lechuga comparing PlanetLab images from 2-15-2021 and 2-23-2021.

HPN4 and glacier dammed lake in Sentinel2 Image from 2-9-2021.

HPN4 Glacier in 1987 and 2015 Landsat imagery.  Red arrow indicates 1987 terminus, yellow arrow 2015 terminus, purple arrows indicate medial moraines

The below is from Pelto (2015 and 2017). In 1987  and 2004 there were five contributing glacier tongues to the downwasting tributary, see below. It is like a bathtub being filled with five taps at once. The purple arrow indicates a medial moraine at the mouth of the valley, signaling the lack of current contribution of the downwasting tributary to HPN4 Glacier.  The medial moraine has shifted east indicating that the main HPN4 Glacier is now flowing into the valley instead of the downwasting tributary being a contributing tributary to HPN4.  By 2015 there is only one contributing glacier tongue to the downwasting tributary, only one tap for this draining bathtub, the other four contributing tongues have retreated from contact with the downwasting tributary.  The medial moraine has spread eastward and some fringing proglacial/subglacial lakes are evident  A closeup 2013 Digital Globe image indicates both fringing ponds-blue arrows, rifts caused by varying flotation-green arrows and expanding supraglacial ponds, red arrows.  The rifts are a sign of instability and typically lead to break up of this portion of the terminus. The downwasting tributary continues to demise faster than HPN4 Glacier, which crosses the valley mouth, hence it is likely that a glacier dammed lake will form and that HPN4 Glacier will continue to flow further east up this valley.

Schaefer et al (2013) discuss the HPN4 Glacier because the main terminus has changed little given its modeled mass balance, and the modeled mass balance to the east appears too negative, which they suggest indicates wind redistribution from the HPN4 to the Pared Sud Glacier just east. Davies and Glasser, (2012)  identify this region of the icefield as retreating faster from 2001-2011 than during any measured period since 1870.  This has led to the formation and expansion of many lakes in the basin Loriaux and Cassasa (2013) . Glasser et al (2016) observed that proglacial and ice-proximal lakes of NPI increased from 112 to 198 km2. The largest expansion this century being at San Quintin Glacier at ~24 square kilometers.

hpn-4 2004

2004 Landsat image showing five contributing tributaries

hpn4-ge

Google Earth image 2013

Tres Puntas Glacier, Chile Loses 50% of its Length this Century

On By mspeltoIn chile glacier melt, chile glacier retreat

Tres Puntas Glacier, Chile in 1999 and 2021 Landsat imagery. Red arrow is 1999 terminus location, yellow arrow the 2021 location, Point A is where tributaries joined in 1999 and Point B is where an adjacent glacier drains west.

Tres Puntas Glacier flow south from Cerro Tres Puntas draining south into Lago O’Higgins in Patagonia. The icefield is east of the Patagonia icefields where Davies and Glasser (2012) noted the nearby (50 km se) Lago Del Desierto glaciers lost 0.6% of its glacier area from 2001-2011, a much higher rate than from 1986-2000.

In 1999 the glacier is 5.6 km long with two significant tributaries joining at 850 m (Point A) before terminating in a proglacial lake at 600 m. The glacier shares a broad divide near Point B with glacier flowing west. In 2002 the snowline is at 1100 m, the terminus is still terminating in the proglacial lake. By 2020 the glacier tributaries have separated and now terminates at 900 m, above Point A. At Point B there is a separation between this glacier and the glacier draining west. By mid-February of 2021 the west tributary has retreated 2.8 km, 50% of its 1999 length, while the eastern tributary has retreated 2.4 km of its 5.0 km length. The snowline in mid-February of 2020 and 2021 has been at 1200 m, above the median glacier elevation. Further retreat of the eastern arm should lead to an additional alpine lake forming.

The retreat of this glacier is more extensive than that of the nearby Sierra Sangra glaciers,  Argentina.  The retreat from an expanding proglacial lake also has played out at Cordillera Lago General Carrera Icefield, Chile

Tres Puntas Glacier, Chile in 2002 and 2020 Landsat imagery. Red arrow is 1999 terminus location, yellow arrow the 2021 location, Point A is where tributaries joined in 1999 and Point B is where an adjacent glacier drains west.

Rio Frio Glacier, Chile Retreat-Lake Formation 1990-2020

On By mspeltoIn chile glacier retreat

Rio Frio Glacier (RF) in 1990 and 2020 Landsat images. Red arrow 1990 terminus, yellow arrow 2020 terminus, orange arrow new lakes formed after 2000, purple dots snow line.

The “Rio Frio” Glacier is at the headwaters of the Rio Frio a tributary to Rio Palena in Parque Nacionale Corcovado of Palena Province of Chile.  Davies and Glasser (2012) noted that overall glaciers in the region lost 14% of their area from 1986 to 2011. Paul and Molg (2014)  assessed changes of glaciers in the Palena district, Chile revealing a  total area loss of 25% from 1985 to 2011.  Area loss below 1000m elevation was 50–100% and the number of proglacial lakes increased from 223 to 327. Carrivick et al (2016) reported the glaciers in the region had an average thickness of 41 m, this is relatively thin allowing for the rapid area loss. Here we examine glacier change from 1990 to 2020 using Landsat imagery.

The Rio Frio Glacier terminated in a proglacial lake in 1990 at 720 m and the snowline is at 1100 m.  The next glacier to the south has two arms terminating at 900 m with no proglacial lakes at the terminus see orange arrows. In 2000 there is limited retreat and Rio Frio Glacier still terminates in the lake, and the snowline is at 1150 m. At the next glaciers south there is no proglacial lakes evident at the terminus. By 2019 Rio Frio Glacier has retreated from the lake and the snow line is at 1100 m at the start of February.  The next glacier south two new proglacial lakes have developed at orange arrows. By 2020 the glacier terminus has retreated 500 m to an elevation of ~880 m.  Rio Frio glacier has lost more than 50% of its area below 1000 m.  The glacier still has maintained an accumulation zone each year indicating that without further warming it can survive. The next glacier south has retreated exposing two new proglacial lakes that now are no longer reached by the glacier.

The large scale loss of these two glaciers is typical for the region as noted by the references above and by the examples of Tic Toc Glacier, Erasmo Glacier and Hornopiren Glacier. In this case the two new proglacial lakes are small and no longer in contact with the glacier, result they pose little glacier outburst flood risk. The lake beyond the terminus of Rio Frio Glacier has neither adjacent significant steep slopes or ice in contact and poses little risk as well.

Rio Frio Glacier in 2000 and 2019 Landsat images. Red arrow 1990 terminus, yellow arrow 2020 terminus, orange arrow new lakes formed after 2000, purple dots snow line.

Is San Quintin Glacier Lake the fastest expanding lake this century in South America?

On By mspeltoIn chile glacier retreat

Landsat images of San Quintin Glacier from 2001 and 2020 indicate the expansion of both Lake A and Lake B due to glacier retreat. The Lake A basin as defined by the transect at the eastern narrow point, yellow line, has a total area of 41 km2 with the lake surface area now comprising 35.1 km2.

San Quintin is the largest glacier of the Northern Patagonia Icefield (NPI) at 790 km2 in 2001, flowing ~50 km west from the ice divide in the center of the ice cap.  San Quintin Glacier terminated largely on land until 1991 (Davies and Glasser, 2012). The velocity at the terminus has increased from 1987 to 2014 as the glacier has retreated rapidly into the expanding proglacial lake (Mouginot and Rignot, 2015).  As Pelto (2016) noted 19 of the 24 main outlet glaciers of the Northern Patagonia Icefield ended in a lake in 2015, all the lake termini retreated significantly in part because of calving losses leading to lake expansion in all cases. Glasser et al (2016) observed that proglacial and ice-proximal lakes of NPI increased from 112 to 198 km2. Loriaux and Cassasa (2013) reported that the combined area of the multiple San Quintin Glacier lakes expanded the most of any NPI from 1945-2011 increasing by 18 km2. The large evident crevasses/rifts perpendicular to the front indicate the terminus tongue has been partially afloat since at least 2014  Here we examine Landsat images from 1987-2020 to illustrate the changes. NASA’s Earth Observatory has high resolution images indicating the terminus in June 2014 and April 2017

In 1987 it is a piedmont lobe with evident minimal marginal proglacial lake development beginning, with an area in Lake A of  3.2 km2 and Lake B of 2.2 km2.  The main lake, Lake A, in 2001 had expanded to an area of 14 km2, while Lake B had expanded to 6.5 km2. The main lake, Point A, had an area of 23.8 km2 in 2011 (Loriaux and Cassasa, 2013) . Lake B developing on the north side of the glacier, due to a 3500 m retreat, by 2015 had an area of 9.2 km2.  For Lake A the main terminus retreat of  2200 m from 1987-2015 and led to lake expansion to 34.3 km2. The southern terminus at Point C, has a narrow fringing lake and a retreat of 1100 meters from 1987-2015.

A narrow terminus tongue extending from the main terminus had an area of 0.6 km2 and extended to within ~1.5 km of  the Lake A western shore in March 2018.   By November 10, 2018 this narrow tongue had disintegrated.   In February 2020 the area of Lake A is 35.1 km2 and Lake B is 9.7 km2, a combined area of 44.8 km2 vs 20.5 km2 in 2001.  Gourlet et al (2015) examined the thickness across sections of the NPI, weather prevented the survey of the terminus area of San Quintin Glacier, but there results do hint that the bed is below sea level between Lake A and B basins, and they should connect. In the Landsat images of 2001 and 2015 a transect across the narrow point at the east end of Lake A indicates an area of 41 km2 if the entire main terminus tongue collapses. The ~24 km2 lake expansion at the two main terminus locations of San Quintin Glacier from 2001-2020 represent the fastest lake expansion from glacier retreat, is it the fastest overall for South America? Steffen Glacier is another example of rapid retreat and lake expansion. The retreat is much less than at HPS-12, but that is an example of fjord expansion.

Landsat images of San Quintin Glacier from 1987 and 2015 indicate the expansion of both Lake A and Lake B due to glacier retreat as well as retreat at Point C.

San Quintin in  March and November 2018 Landsat images indicating loss of narrow terminus tongue pink dots.

Soler Glacier Retreat and Lake Expansion

On By mspeltoIn chile glacier melt, chile glacier retreat

Soler Glacier in 1987 and 2020 Landsat images.  Red arrow indicates 1987 terminus location, yellow arrow indicates 2020 terminus location on north side of glacier.  Yellow dots indicate margin of lake and purple arrows indicate specific locations where glacier thinning is evident.

Soler Glacier is an outlet glacier on the east side of the Northern Patagonia Icefield (NPI). The terminus response of this glacier has been slower and more limited than on most NPI glaciers.  Aniya and Fujita (1986)  reported a total retreat of 200-350 m from 1944 to 1984.  Glasser et al (2016) note the recent 100 m rise in snowline elevations for the NPI, which along with landslide transport explains the large increase in debris cover since 1987 on NPI from 168 km2 to 306 km2 .  Loriaux and Casassa (2013) examined the expansion of lakes on the Northern Patagonia Ice Cap reporting that from 1945 to 2011 lake area expanded 65%, 66 km2. For Soler Glacier lake formation did not occur until the last decade and debris cover has changed little as well. Willis et al, (2012) identified thinning of ~2 m/year in the ablation zone from 1987-2011. This thinning is now leading to the development of a significant proglacial lake that is examined using Landsat images from 1987-2020.

In 1987 the glacier is still up against the Little Ice Age moraine, though it had thinned considerably resulting in retreat down the slope of this vast moraine. By 2000 a small lake had developed both on the north and south side of the main terminus with a total area of ~0.3 km2, red dots. In 2016 and 2019 this lake had expanded, with the northern arm mostly filled with ice, orange dots.  In October 2020 the lake has an area of ~1 km2 and is mostly open water. The extensive thinning of the terminus tongue continues to drive both retreat and lake expansion.  The thining is evident at Point A where bedrock knobs have emerged from the ice near the snowline.  The three purple arrows on the south side of the glacier indicate thinning as these bedrock features are increasingly distant from the glacier. The terminus has retreated 500 m in the glacier center, 2100 m on the north side and 1300 m on the south side from 1987-2020.  The terminus tongue in its lowest 1.5 km continue to thin and will collapse in the lake in the near future. The end of summer snowline has averaged 1450 m in recent years leading to continued mass loss without calving in the lake (Glasser et al 2016).

Lake development here lags that of other glacier around the NPI such as Exploradores, Nef, Steffen and San Quintin.

Soler Glacier in 2000 and 2019 Landsat images.  Red arrow indicates 1987 terminus location, yellow arrow indicates 2020 terminus location on north side of glacier.  Red dots  and orange dots indicate margin of lake.

Soler Glacier in 2016 Landsat image.  Red arrow indicates 1987 terminus location, yellow arrow indicates 2020 terminus location on north side of glacier.  

Darwin Glacier, Chile 1986-2020 Retreat Opens New Fjord Arm

On By mspeltoIn chile glacier melt, chile glacier retreat

Darwin Glacier in Landsat images from 1986 and 2020. Red arrow indicates 1986 terminus location, yellow arrow 2020 terminus location, purple dots the snowline.  Point 1,2 and 3 indicate the same specific location.

Darwin Glacier flows east from the main divide of the Cordillera Darwin entering the head of Fjord Parry. Here we examine changes illustrated by Landsat images from 1986-2020.   Melkonian et al (2013) note widespread thinning of four large glaciers in the Cordillera Darwin Range from 2000-2011; Ventisquero Grande, Marinelli, Darwin and Roncagli, while the Garibaldi Glacier increased in volume.  They note a maximum velocity of 9.6 m/day at Darwin Glacier and thinning of over 3 m/year during the 2000-2011 period, which emcompasses a period of rapid retreat noted below. Davies and Glasser (2012) note that during the 1870-2011 period the Cordillera Darwin area loss was most rapid from 1986 to 2001. Dussaillant et al (2019) note the mass loss for the central Cordillera Darwin at -0.4 to -0.6 m/year from 2000-2018.

In 1986 Darwin Glacier extended beyond the end of a southwest trending valley (Point 3) and had fully separated from the former tributary flowing eastward. Tributaries at Point 1 and 2 join the main glacier within a 2 km of the current terminus. The snowline is at 500 m. By 2000 the glacier had retreated into the southwest trending valley, with a peninsula emerging on the west side at point 3.  The snowline is at 500 m. By 2019 the glacier had retreated beyond the former tributaries at Point 1 and 2. The snowline in 2018 is at 750 m.  In 2020 the peninsula at Point 3 has greened up with new vegetation, the glacier has retreated 3100 m since 1986 exposing a new fjord arm. Point 2 is largely a glacier free valley bottom.  The snowline is at 800 m.  A further 1 km retreat will lead to another tributary separation much as has happened at Ventisquero Grande.

Darwin Glacier in Landsat images from 2000 and 2019. Red arrow indicates 1986 terminus location, yellow arrow 2020 terminus location, purple dots the snowline.  Point 1,2 and 3 indicate the same specific location.

GLIMS view of Darwin Glacier with 1986-2007 margins indicated (Bethan Davies delineated margins).  Flow arrows added.