Abstract. Formation and development of glacial lakes in mountain regions is one of the consequences of glacier recession.
10Such lakes may drain partially or completely when the stability of their dam is disturbed. We presented a case study from Central-Asian mountain range of Tien Shan, a north-oriented tributary valley Adygine, where a glacier retreat resulted in formation of several generations of lakes. The aim of this study was to analyse past development of different types of glacial lakes influenced by the same glacier, to project site's future development, and to evaluate the hazard of individual lakes with an outlook for expected future change. We addressed the problem with a combination of methods, namely bathymetric, 15 geodetic, and geophysical on-site survey, satellite image and DEM analysis, and modelling of glacier runoff evolution. Based on the case of glacial lakes of varied age and type, we demonstrate the significance of glacier ice in lake's development. Lake 3, which is in contact with glacier terminus, has changed rapidly over the last decade, expanding both in area and depth and increasing its volume more than 13 times (7 800 m 3 to 106 000 m 3 ). Hydrological connections and routing of glacier meltwater proved to be an important factor as well, since most lakes in the region are drained by subsurface channels. Within the hazard 20 evaluation of lakes, we highlighted the importance of field data which can provide crucial information on lake stability. In our case, the understanding of site's hydrological system and its regime helped to categorise Lake 2 into low outburst hazard, while Lake 1 and Lake 3 were labelled as medium hazard lakes. Further development of the site will be driven mainly by rising air temperature and increasingly negative glacier mass balance. All three scenarios predict a significant glacier area decrease by 2050, specifically leaving 73.2 % (A1B), 62.3 % (A2), and 55.6 % (B1) of the 2012 glacier extent. The glacier retreat will be 25 accompanied by changes in glacier runoff with first peak expected around the year 2020.