The Sierra Nevada del Cocuy is the second largest concentration of glaciers in Colombia. The glaciated area in Colombia is at 6º30′ N and 72º20′ W and extends along the crest of this range. Morris et al (2006) documented the decline in total area from 39.1 square kilometers to 16.3 square kilometers in 2003. Poveda and Pineda (2009) estimated glacier area of as 28.6 km2 in 1989, 22.9 km2in 2000, and 17.00 km2 in 2007. A 40% decline in area in two decades. This post follows up on an earlier post that examined changes in southern half of the glaciated range. This post looks at the glaciers at the northern edge of the range using Landsat images from 1988 and 2012 and a Geoeye image from 2009. The glaciers are on the flanks of Ritacuba Blanco Peak and Aguja Peak, inside the burgundy circle in the map below. The image below is a combined Landsat image with a 1988 image on top and a 2012 image below. Each arrow is a different color and number, pointing to the same glacier or feature. Glaciers 1-3 are on the east flank of Aguja Peak, Glacier 4 on the norhwest side of Ritacuba Blanco. In 1988 glaciers 1-4 have respective areas of: 1=0.3 km2, 2=0.4 km2, 3=1.1 km2 and 4=0.35 km2. By 2012 the areas are: 1=0.05 km2, 2=0.2 km2, 3=0.5 km2 and 4=0.08 km2. Glaciers 1 and 4 are nearly gone. Glacier 1 and 2 exhibit limited snowcover, lighter blue, indicating a lack of accumulation, and even short term survival is not possible (Pelto, 2010). Glacier number 5 and 6 are on the west side of Ritacuba Blanco. In 1988 the two main glaciers end near the margin of recently formed lakes indicated by the blue and orange arrows. By 2012 retreat from the the margin of these lakes exceeds 500 meter in both cases. For glaciers that were less than 1500 meters long, this is a substantial retreat. An additional view of the region is provided in Google Earth and Glacier 5 is seen at the northern edge of a Geoeye image from 2009. Indicating the distance of retreat from the lake near the 1988 glacier margin. Both glaciers on the west flank of Ritacuba Blanco exhibit consistent snowcover presence on their upper reaches above 5000 meters, indicating they have the potential to survive current climate at a reduced size. An expedition to the mountain and the glacier indicate what the area looks like. The bottom image is from a 2012 expedition to Ritacuba Blanco
The Sierra Nevada del Cocuy is the second largest concentration of glaciers in Colombia. The glaciated area in Colombia is at 6º27′ N and 72º18′ W and extends along the crest of this range. Morris et al (2006) documented the decline in total area from 39.1 square kilometers to 16.3 square kilometers in 2003. Poveda and Pineda (2009) estimated glacier area of as 28.6 km2 in 1989, 22.9 km2in 2000, and 17.00 km2 in 2007. A 40% decline in area in two decades. This post examines Landsat images from 1988 and 2012 and a Geoeye image from 2010. In the first image from 1988 identifies key local geographic localities, Laguna Grande de la Sierra (LGS), Laguna Grande de la Plaza (LGP), Concavo (C) Pulipito del Diablo (PD). The purple arrow indicates the separation of the main ice mass on PD from the arm extending north in 2010 (middle) and 2012 (bottom). The yellow arrow indicates the retreat of the glacier descending from Concavo toward LGS, from 1988 to 2012 the retreat has been 300 meters from 1988 to 2012. The glacier has declined from 1500 meters to 1200 meters in length. The red arrows indicate the separation of the Concavo glaciated summit and the arm of the glacier that extended to the north. What we see is the separation of a continuous ice mass along the crest of the Sierra del Concuy. Poveda and Pineda (2009) ask whether the glaciers will disappear during the 2010-2020 decade. Glaciers disappear because they lack a consistent and persistent accumulation zone (Pelto, 2010), we cannot just extrapolate onn glacier area decline. In this case the losses indicate continued segmentation and separation, but clearly there are several key areas that have substantial area and will not disappear within the decade. There is insufficient data to identify if any of the glacier retain sufficient snowcover to be sustained with current climate.