Outburst flood forecasting by monitoring glacier-dammed lake using satellite images of Karakoram Mountains, China

Glacier lake outburst floods (GLOFs) that originate in the Shaksgam Valley on the northern slope of the Karakoram Mountains (China) occur frequently and they cause many local and regional disasters in the Yarkant River basin. In order to monitor and assess their hazard potential, this study used both HJ-1A/B and Landsat TM/ETM+/OLI satellite images to investigate the formation-drainage processes of the Kyagar glacier-dammed lake since 2009. Results show that four formation-drainage processes of the lake occurred with estimated maximum lake water volumes of 50.7 × 106, 49.8 × 106, 49.2 × 106, and 34.9 × 106 m3 in 2009, 2015, and in July and August 2016, respectively. A statistical relationship based on the observed lake water volume and peak discharge at the hydrometric station during 1959-2008 was found relatively effective for forecasting peak GLOF discharge with an average relative error of ∼24% in comparison with observed values at the hydrometric station. Dynamic changes of the Kyagar Glacier, especially its advances since 2013, were directly responsible for the repeated thickening of the glacial dam and formation of the lake. This study provides an effective method for monitoring and forecasting GLOFs in the Yarkant River basin.