Rapid advance of two mountain glaciers in response to mine-related debris loading

Abstract

Rapid glacier advance is known to occur by a range of mechanisms. However, although large-scale debris loading has been proposed as a process for causing rapid terminus advance, it has rarely been observed. We use satellite remote sensing data to observe accelerated glacier terminus advance in response to massive supraglacial loading on two glaciers in Kyrgyzstan. Over a 15year period, mining activity has led to the dumping of spoil of up to 180m thick on large parts of these valley glaciers. We find that the termini of these glaciers advance by 1.2 and 3.2km, respectively, at a rate of up to 350myr-1. Our analysis suggests that although enhanced basal sliding could be an important process, massive supraglacial loads have also caused enhanced internal ice deformation that would account for most, or all, of the glacier terminus advance. In addition, narrowing of the glacier valley and mining and dumping of ice alter the mass balance and flow regime of the glaciers. Although the scale of supraglacial loading is massive, this full-scale experiment provides insight into glacier flow acceleration response where small valley glaciers are impacted by very large volumes of landslide debris. Key Points Mining spoil is dumped on two glaciers in Kyrgyzstan The glaciers advance rapidly due to massive supraglacial debris loading Glacier behavior is an analogue for large landslides impacting small glaciers