September 9, 2020
Khasankoi Glacier in 1985, 1998, 2013 and 2020 Landsat imagery with Point 1-4 indicating locations where bedrock expansion is occurring with Point 1 and 3 separating the glacier into three parts. Note complete lack of snowcover on 8-26-2020.
Khasnakoi Glacier is a north facing slope glacier just south of Mount Elbrus that drains into the Kuban River. The Greater Caucasus contain approximately 2000 glaciers with a total area of ~1200 km2(Tielidze and Wheate, 2018). Significant positive trends in annual and summer temperature from 1960-2014 have driven large overall glacier area loss, 0.53% per year, leading to the loss of over 300 glaciers (Tielidze and Wheate, 2018). Here we examine Landsat images from 1985-2020 to identify key changes of the glacier.
In 1985 the glacier extended 4.6 km from east to west without interruption and featured three primary termini. The glacier in 1985 has an accumulation area ratio (percent snowcovered) of 60%. By 1998 there is limited retreat the glacier is still once continuous glacier and the accumulation area ratio is 40. By 2013 at Point 1 a bedrock ridge is emerging. At Point 2 a few outcrops of rock are evident emerging from under the thinning glacier. The same is the case at Point 4. At Point 5 a new lake has developed at the margin. The accumulation area ratio in 2013 is 25%. In 2020 the accumulation area ratio is 0% snowcover. A pair of ridges now bisect the glacier at Point 1 and Point 3. At Point 2 the rock outcrop has expanded into one large region. At Point 4 a bedrock area has expanded at the head of the glacier. At Point 5 retreat has left the newly formed lake of less than a decade ago isolated from the glacier. This is not the first year of poor snowcover.
The mapped boundary of the glacier below provided by Levan Tieldze illustrates the glacier boundary in 1960, 1986 and 2014, illustrating a 29% decline in area. The loss of snowcover in 2020 is not the first summer when this has been observed in the Caucasus in 2017 Gora Gvandra did not retain snowcover. For Dzhikiugankez Glacier on the slopes of Mount Elbrus there has been a persistent low snowcover by end of summer since 2013. Tieldze (2019) explained the connection of climate to receding glaciers in the Caucasus using Tviberi Glacier in Georgia as an example.
Image from Levan Tieldze indicating the extent of the glacier in 1960 (red), 1986 (black) and 2014 (blue) on a 2016 SPOT image. There is still some connection above Point 1.
Map of the region from when Khasankoi Glacier was contiguous.