Spatial and Temporal Evolution of Glacier Lakes in the Hindukush Region of Afghanistan (HKA)

Abstract

Rapid climate change is leading to global loss of snow and ice from the world’s cryosphere and mountain glaciers. Of particular concern is the changing risk related to rapid melt of snow and ice, shrinking of glaciers, and eventual expansion and formation of new glacial lakes. If these breach then glacial lake outburst floods (GLOFs), potentially catastrophic, may result. One region in the Himalayas-Hindukush where glacier lake formation and GLOF behavior is very poorly known is Afghanistan. The country’s geographical location and climate leave it highly exposed to GLOFs. Several lakes have burst and caused GLOFs as reported across the HKH region. In Afghanistan, a catastrophic GLOF recently occurred in Panjshir, upstream of Kabul (on 12 July 2018), with an impact foot print of 55126m2 that devastated the village of Peshghor with significant socio- economic losses and also dammed the Panjshir River up to 1.7 km from the river confluence.The absence of an up-to-date, multi-temporal and high-resolution inventory of Afghanistan's glacier lakes is seen as a significant obstacle. Such lakes are extremely remote and difficult to map and to monitor in the ground. In this study the spatial and temporal evolution of glacier lakes in the Hindukush region of Afghanistan (HKA) is conducted from Landsat imagery to make a time series with three dates; 1990, 2015 and 2020. For this purpose, we applied geospatial techniques using Landsat 8, Operational Land Imager (OLI) and the Normalized Difference Water Index (NDWI) is proposed in this paper.Initial findings indicate that the number and area of glacial lakes increased continuously from 1990 to 2015, increased by 8% and 10% respectively to give a total of 1942 glacier lakes covering an area of 89km2 by 2015.The outcomes of the proposed study will be useful and effective for GLOF risk reduction management and development of an overall strategy to address possible risks from future GLOFs events in the country, in order to develop the capacity of downstream vulnerable communities to mitigate impacts of this events.Key words: Glacier Lakes, Glacier Lake outburst flood, Landsat data, NDWI, Peshghor GLOF, Hindukush region, Afghanistan.