Glacial lake outburst floods (GLOF) occur due to the failure or overtopping of the dam of a glacial lake. These floods are characterised by low frequency of occurrence but high magnitude. Peak discharge of GLOF may overcome peak discharge of „classical“ hydrometeorologically-induced flood by several times, thus GLOFs represent significant hazardous process, especially in high mountain areas where glacier retreat leads to the formation and evolution of glacial lakes. Understanding to the spatiotemporal patterns of GLOFs occurrence is essential for more advanced GLOF risk management.
The main objective of the study published in top-ranked glaciological journal The Cryosphere in April 2018 was to analyse occurrence of GLOFs from moraine-dammed lakes and the relationship to climate change since the end of Little Ice Age (LIA) on global scale. The international team of authors led by Stephan Harrison (Uni Exeter) with the contribution of CzechGlobe (Adam Emmer), built globally most complete database of GLOFs from moraine-dammed lakes and put the frequencies of their occurrence into the context of changing climate.
It was shown that individual regions react to post-LIA climate change with different lag times on three levels: (i) the lag time between the LIA and the formation of a lake; (ii) the lag time between lake formation and the occurrence of GLOF; and (iii) the lag time between LIA and the peak frequency of GLOF occurrence on regional scale. While some regions have already undewent the period of peak frequency of GLOF occurrence (e.g., peruvian Cordilera Blanca from late 1930’s to early 1950’s), in other regions is still yet to come (e.g. Central Himalayas). The results of the study are also noted by GlacierHub portal.
Harrison, S., Kargel, J.S., Huggel, C., Reynolds, J., Shugar, D.H., Betts, R.A., Emmer, A., Glasser, N., Haritashya, U.K., Klimeš, J., Reinhardt, L., Schaub, Y., Wilyshire, A., Regmi, D., Vilímek, V. (2018): Climate change and the global pattern of moraine-dammed glacial lake outburst floods. The Cryosphere, 12, 1195-1209.