Inventory and evolution of glacial lakes since the Little Ice Age: Lessons from the case of Switzerland

Abstract

Retreating glaciers give way to new landscapes with lakes as an important element.In this study, we combined available data on lake outlines with historical orthoimagery and glacier outlines for six time periods since the end of the Little Ice Age (LIA; $1850). We generated a glacial lake inventory for modern times (2016) and traced the evolution of glacial lakes that formed in the deglaciated area since the LIA. In this deglaciated area, a total of 1192 lakes formed over the period of almost 170 years, 987 of them still in existence in 2016. Their total water surface in 2016 was 6.22 AE 0.25 km 2 . The largest lakes are > 0.4 km 2 (40 ha) in size, while the majority (> 90%) are smaller than 0.01 km 2 . Annual increase rates in area and number peaked in 1946-1973, decreased towards the end of the 20th century, and reached a new high in the latest period 2006-2016. For a period of 43 years , we compared modelled overdeepenings from previous studies to actual lake genesis.For a better prioritization of formation probability, we included glacier-morphological criteria such as glacier width and visible crevassing. About 40% of the modelled overdeepened area actually got covered by lakes. The inclusion of morphological aspects clearly aided in defining a lake formation probability to be linked to each modelled overdeepening. Additional morphological variables, namely dam material and type, surface runoff, and freeboard, were compiled for a subset of larger and ice-contact lakes in 2016, constituting a basis for future hazard assessment.

Progress and challenges in glacial lake outburst flood research (2017–2021): a research community perspective

“…Aggarwal et al, 2017;Muneeb et al, 2021;Rinzin et al, 2021), while statistic-based studies building on rigorous analysis of previous GLOFs are rare (McKillop and Clague, 2007a, b;Fischer et al, 2021). For a given lake, characterizing the current conditions and those prior to outburst remains challenging, highlighting the need for comprehensive regional lake inventories and lake evolution studies (Petrov et al, 2017;Buckel et al, 2018;Wilson et al, 2018;How et al, 2021;Lindgren et al, 2021;Mölg et al, 2021;Wood et al, 2021;Andreassen et al, 2022), global lake inventories (Shugar et al, 2020), regional GLOF inventories (e.g. Bat'ka et al, 2020;Emmer et al, 2022) and global GLOF inventories (Veh et al, 2022).…”

The 28 November 2020 Landslide, Tsunami, and Outburst Flood – A Hazard Cascade Associated With Rapid Deglaciation at Elliot Creek, British Columbia, Canada

“…Further, surface inversion techniques for predicting topography below current glaciers (Farinotti et al., 2019) have evolved to allow mapping of future lake locations (Zheng et al., 2021). Combining these data with existing (Clarke et al., 2015) and new (Edwards et al., 2021) glacier evolution projections will allow researchers to assess recently exposed lakes (Mölg et al., 2021; Shugar, Burr, et al., 2021) and model future lakes as they develop throughout the remainder of this century. Modeled and measured permafrost degradation and debuttressing data could be used to classify dangerous slopes (e.g., Allen et al., 2022; Deline et al., 2021; Haeberli et al., 2017).…”

The role of thermokarst evolution in debris flow initiation (Hüttekar Rock Glacier, Austrian Alps)

“…Dividing the latest lake water volume estimate (∼166,000 m 3 ) by the drainage time (∼1 day) indicates a drainage rate on the order of ∼m 3 s -1 , supplying a substantial amount of water to the debris flow initiation zone. In contrast to many hazardous glacial lakes evolving over time scales of years to decades (Haeberli, 1983;Mölg et al, 2021), the thermokarst lake in Hüttekar-cirque unfolded its destructive power already two months after its formation.…”

“…Moreover, glacier retreat enhances the accumulation of loose, unstable sediment at high elevations (Stoffel and Huggel, 2012;Deline et al, 2015;Buckel et al, 2018;Hock et al, 2019;Mölg et al, 2021). These changing environmental conditions alter the geotechnical and hydraulic ground properties, and modify the characteristics and seasonality of landslides accordingly (Stoffel and Huggel, 2012;Gariano and Guzzetti, 2016;Beniston et al, 2018;Patton et al, 2019).…”