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Hazard assessment of glacial lake outburst floods from Kyagar glacier, Karakoram mountains, China

HAEMMIG C., HUSS M., KEUSEN H.R., HESS J., WEGMÜLLER U., AO Z., KULUBAYI W. (2014)

Annals of Glaciology (55)66 2014

Kyagar glacier is located in the Chinese Karakoram mountains. The glacier tongue entirelyblocks the riverbed in the upper Shaksgam valley and impounds a glacial lake, which was the source ofseveral violent and disastrous glacial lake outburst floods (GLOFs).

A GLOF early warning system wasimplemented between 2011 and 2013. We present an integrative analysis of the hazard potential ofKyagar lake, taking into account the ice flow dynamics of Kyagar glacier as well as the recent surfacemass-balance response to climate change. Comparison of two high-resolution digital elevation models(DEMs) for the ice dam shows surface lowering rates of >5ma–1 between 2002 and 2011, leading to asignificant reduction in the maximum potential lake volume.

However, two DEMs covering the entireglacier for the period 2000–10 indicate mass gains in its central part, and flow speed measurementsshow an acceleration in this region. This pattern of local ice-thickness changes combined with varyingice flow velocities is typical for surge-type glaciers. The velocity of the glacier surface and of the ice dambetween 2011 and 2012 are analyzed at high temporal and spatial resolution, based on feature trackingof synthetic aperture radar (SAR) images.