Posts Tagged georgia glacier retreat

Khimsa Glacier Retreat, Georgia

Khimsa Glacier is a rare significant glacier south of the main crest of the Caucasus Mountains in Georgia. The glacier drains north to the Bzyb River, and then the Black Sea. The rivers upper reach is quite undeveloped and there is no hydropower along the river to date. The glacier flows from an elevation of 3000 m to 2650 m. In 1998 the glacier was 1.6 km long with a narrow terminus at the red arrow. At the transition to the glacier’s upper eastern slopes at Point A, there is only one small rock exposure. By 2013 the glacier has retreated 400 m to the yellow arrow, having lost 25% of its length in 15 years. The area of bedrock exposed on the upper eastern slope, at Point A, is significant now indicating thinning even high on the glacier. The glacier will soon separate near Point A into an upper and a lower section. In the Google Earth image the current terminus is indicated with orange dots and the glacier flow with blue arrows. Like Psysh Mountain glaciers 25 km north Khimsa Glacier thinning high on the glacier indicates it cannot survive current climate. Caucasus Mountain glaciers are in a period of rapid retreat (Shagedenova et al, 2009), that is attributed mainly to rising summer temperatures. Khimsa Glacier’s retreat parallels that of glaciers along the main crest of the Caucasus such as Kirtisho or Azau Glacier, though as a percent of total area lost it is greater.

khimsa glacier 1998
1998 Landsat image

khimsa glacier 2013
2013 Landsat image

khimsa ge

2010 Google Earth image

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Kirtisho Glacier Retreat, Georgia

The southern flank of the Caucasus Mountains is in the nation of Georgia. Ten kilometers southwest of the Lednik Karaugom Glacier, Russia from the previous post is Kirtisho Glacier a 4.5 km long valley glacier, a small subglacier KS is also examined in this post.caucasus submap The glaciers in the Causcasus Mountains have been undergoing a significant retreat, the USGS, (2010) Satellite Image Atlas of Asia, noted that nearly all of the 65 glaciers examined in this region experienced significant retreat from 1987-2004. Shahgedanova et al, (2009) noted a 8 meters per year average retreat rate for the 1985-2000 period. To get a feel for the terrain watch the trailer for the On the Trails of the Glaciers- Caucasus 2011. The video does not show Kirtisho Glacier but does indicate the nature of the terrain. This is a project of an Italian group Macromicro, that had contacted me about an upcoming expedition to Alaska in 2013. Landsat images from 1986 (second image) and 2012 (third image) along with 2011 Google Earth imagery (top and bottom image) are shown below. Kirtisho Glacier has a top elevation of 3700 meters and a terminus that in 2012 is at 2600 meters, and was 2400 m in 1986. The snowline has typically been at 3300 meters, blue arrow, which is too high to sustain the terminus at 2600 m. The terminus position in 1986 is indicated by a red and yellow arrow that are also used in the 2012 imagery and the 2011 terminus closeup. The magenta arrow in the Landsat images indicates the beginning of a separation from an northern tributary, which is close to the snowline. The terminus itself is not crevassed in the lowest 400 meters, suggesting retreat will continue for this nearly stagnant section. KS the small glacier to the south, has decreased in area from 0.45 km2 in 1986 to 0.20 km2 in 2012. We also examine this more below. kirtisho glacier profile

kirtisho 1986Kirtisho 2012

kirtisho terminus The KS glacier viewed up close is quite thin, with limited crevasses. The red arrows indicate rock protruding through this glacier in many locations. These rocks indicate how thin the ice is, and will help absorb heat and hasten melting as the rock outcrops expand. In 2011 and in the 2012 imagery there is no remaining snow on the glacier. A glacier without a persistent accumulation zone cannot survive (Pelto, 2010). KS glacier will not survive much longer. ks 2011

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