The West Barun Glacier flows southwest from Baruntse Peak at 7100 meters ending at Barun Khola (lake) at 4500 meters. Comparison of images from 1992, 2003 and 2009 indicate the retreat of the glacier and expansion of the lake. In the early 1990’s the lake was observed to be 1100 meters long with an area of 0.66 square kilometers (ICIMOD, 2010). In 2003 the lake was 1500 meters long. In 2009 the lake was 2000 meters long and had an area of 1.4 square kilometers having doubled in size. In 2013 the maximum length of the lake is 2700 m and the area 1.5 to 1.6 square kilometers. The importance of such lakes impounded in part by moraines, is the potential for glacier lake outburst floods (GLOF). The Barun Khola has no specific date for a GLOF observed, but does pose a risk and has produced floods as indicated by Pradeep Mool (2001) in Figure 1 of the ICIMOD (2010) report, reproduced here, Band C are Barun Khola. ICIMOD has examined this hazard extensively in Nepal and particularly the Dudh Khosi Basin. To date the Dudh Khosi does not have main stem hydropower, but a 210 MW plant is in development. An examination of Landsat imagery from 1992 and 2009 along with Google Earth imagery from 2003 and 2009 is used to identify the retreat. The red line in the Google earth images is the 1992 terminus, the orange line the 2003 terminus and the green line the 2009 terminus. The glacier is outlined in magenta in the Landsat images. The glacier retreated 270 meters, 25 m/year), from 1992 to 2003. From 2003 to 2009 the glacier retreated an additional 480 meter, 80 meters per year. In the 2013 Landsat image the southern portion of the terminus has not markedly retreated since 2009, but the lake expansion continues on the northern shore of the lake., pink arrow.
1992 Landsat image
2003 Google earth image
2009 Google Earth image
2009 Landsat image
2013 Landsat image
A closeup view of the terminus from Google Earth indicates lots of icebergs near the ice front, magenta arrows. The icebergs in the Landsat image later in 2009 have drifted further from the glacier. The angular nature of the icebergs indicates recent large calving event. There are also some small lakes on the surface of the glacier, yellow arrows.
This glaciers retreat and lake expansion is like the nearby North Lhonak Glacier, Middle Lhonak Glacier, Imja Glacier and Nobuk Glacier.
Colonia Glacier drains east from the Northern Patagonia Icefield feeding the Baker River, Chile. The recent substantial retreat of Colonia Glacier like Glacier Nef just to its north is posing new hazards. The glacier is unusual in the number of lakes that are adjacent to or feed into the adjacent glacier damed or proglacial lakes. In the image below Lake A=Arco Lake, Lake B=East Terminal Lake, Lake C=Cachet 1 , Lake D= West terminal Lake, Lake E=Colonia Lake and Lake F=Cachet 2. The glaciers recent retreat and glacier lake outburst floods have been closely monitored by the Laboratorio de Glaciología in Valdivia, Chile.Aniya and others (1999)observed that Colonia Glacier began a rapid retreat after 1985
Superimposition of a RADARSAT image from 1997 and a Landsat 1987 image indicated a retreat of
400 m, from 1997-2005 the retreat has further accelerated, with a general frontal retreat of 2.5 km. Rivera and others (2007) observed that the Colonia Glacier had lost 9.1 square kilometers of area from 1979-2001, which is 3% of the total glacier area. The Laboratorio de Glaciologia’s
In the spring of 2008 Baker River suddenly tripled in size, in less than 48 hours, roads, bridges, and farms were severely damaged. Lake Cachet 2 had vanished the 5 square kilometer glacial lake had emptied 200 million cubic meters of water in just a matter of hours. This lake drained beneath the glacier after sufficient water had filled the lake to buoy part of the glacier and subglacial conduits had begun to develop. Since Cachet 2 emptied in April 2008, the lake has emptied five more times October,
December 2008, March and September 2009 and March 2010, with peak flows released of 3000 cubic meters per second. Below are images of Cachet 2 half- full in Google Earth Imagery from Sept 2008 (note trimline above lake), and full after the flood on 5/28/2008 and empty on 4/8/2008, and lastly the image of the Colonia River’s wide fresh braided stream channel flowing into the Baker River. The newly deposited material from the flood is what makes the wide braided valley such a fresh sediment brown color. The two lakes at the terminus of the glacier did not exist in 1979, the western most terminus lake (B) drained into the easternmost terminus lake (D) via a sub-glacial tunnel after formation in the late 1980’s until 2005 when a channel was cut right through the glacier terminus. This is evident in the image below, there is still glacier ice on both sides of this drainage channel. The development and demise of glacier dammed lakes and the resultant problem of glacier lake outburst floods is not rare today, Imja Glacier, and Tulsequah Glacier are other examples. In the case of Baker River the outburst floods are a threat to the planned hydropower developments as documented by Dusaillant and others (2009). The Colonia Glacier retreat mirrors that of Glacier Nef the next major glacier to the north. Hidroaysen Project is proposing 5 dams on the Baker and Pascua River generating 2750 MW of power. Glacier Nef retreated 3400 m from 1945-2000, 2400 m retreat of the retreat occurred in the 1994 collapse of the terminus tongue into the proglacial lake, which is now 3.5 km long. This retreat includes that of , Gualas GlacierReichert Glacier, Steffen Glacier, and Nef Glacier.