Temporal Variation inventory of Glacier and Pro-glacial Lake and (GLOFs) in Teesta basin (Sikkim) using GIS and Remote Sensing technique

Abstract In high mountainous terrains, with the melting of glaciers, the risk of glacial related hazards increases. One of these risks is Glacial Lake Outburst Floods (GLOFs). As glaciers retreat, glacial lakes form behind moraine or ice ‘dams’. These ‘dams’ are comparatively weak and can breach suddenly, leading to a discharge of huge volume of water and debris. Such outbursts have the potential of releasing millions of cubic meters of water in a few hours causing catastrophic flooding downstream with serious damage to life and property. Mass of the pro-glacial lakes are rapidly growing in response to climate change and glacier retreat which may lead to catastrophic socio-economic disasters. The failure of moraine-dammed lakes is associated with hazard for mountain communities due to high velocity and depth with destructive ability of glacial lake outburst foods (GLOFs). Therefore, assessment of pro- glacial lake development and food impacts in downstream. As a result, total 23 glacial are found in upper Teesta basin area is 5536.48 km2. 4500 to 6000 meters height area is 2036.25 km2 and more than 6000 meters area is 124.93 km2 and the entire glacier are located at above 4500 meters. In addition,. Glacier lake code 14, 13, 2, 15, 18,4 and area are 1.24, 0.49, 0.37, 0.22, 0.8, 0.09 Km2 respectively during 1976 to 2020. Due to increasing lake size could increase the frequency of outburst and cause socio-economic damages in downstream area. The flooding contributed due to lack of awareness of GLOF hazard and non-existence of land-use planning. Therefore, this study anticipated supporting the decision-makers to prepare the management plan in response to futuristic climate scenario and risk measures with inclusive of GLOFs; also suggested to utilize the glacial lakes as reservoir to reduce the risk for mountain communities. Based on the future project ions of snowmelt, the earlier snow-melting or shifts have been observed in extreme high and low elevation areas of the Sikkim Himalaya.