An integrative method for identifying potentially dangerous glacial lakes in the Himalayas

Steiner

et al. 2023

Preprint

Abstract. Glacier lake outburst floods (GLOFs) have been intensely investigated in High Mountain Asia (HMA) in recent years and are the most well-known hazard associated with the cryosphere. As glaciers recede and surrounding slopes become increasingly unstable, such events are expected to increase, although current evidence for an increase in events is ambiguous. Many studies have investigated individual events and while several regional inventories exist, they either do not cover all types of GLOF or are geographically constrained. Further, downstream impacts are rarely discussed. Previous inventories have relied on academic sources and have not been combined with existing inventories of glaciers and lakes. In this study, we present the first comprehensive inventory of GLOFs in HMA, including details on the time of their occurrence, processes of lake formation and drainage involved as well as downstream impacts. We document 682 individual GLOFs that occurred between 1833 and 2022. Of these, 20 % were recurring events from just three ephemeral ice-dammed lakes. In combination, the documented events resulted in 6907 fatalities, with 6000 of these linked to a single GLOF, three times higher than a previous assessment for the region. The integration of previous inventories of glaciers and lakes within this database will inform future assessments of potential drivers of GLOFs, allowing more robust projections to be developed. The database and future, updated versions, are traceable, version controlled and can be directly incorporated into further analysis.

Section: Statistics Of Lakes With and Lakes Without Glofsmentioning

confidence: 98%

HMAGLOFDB v1.0 – a comprehensive and version controlled database of glacier lake outburst floods in high mountain Asia

Steiner

et al. 2023

Preprint

“…Combining the lake and GLOF inventories allows for a comparison of topographic as well as meteorological conditions which may have contributed to the occurrence of GLOFs and those that did not. This is useful for the identification of potentially dangerous glacial lakes (Ahmed et al, 2022;Ashraf et al, 2021Ashraf et al, , 2012Bajracharya et al, 2020;Bolch et al, 2008;Duan et al, 2020;Zhang et al, 2022b). The evaluation of meteorological conditions would require an in-depth discussion of the respective datasets and wider synoptic conditions, attempted previously for mudflows (Mamadjanova et al, 2018).…”

Section: Comparisons To Other Regional Datamentioning

confidence: 99%

A comprehensive and version-controlled database of glacial lake outburst floods in High Mountain Asia

Shrestha,

Steiner,

Shrestha

et al. 2023

Earth Syst. Sci. Data

Self Cite

Abstract. Glacial lake outburst floods (GLOFs) have been intensely investigated in High Mountain Asia (HMA) in recent years and are the most well-known hazard associated with the cryosphere. As glaciers recede and surrounding slopes become increasingly unstable, such events are expected to increase, although current evidence for an increase in events is ambiguous. Many studies have investigated individual events, and while several regional inventories exist, they either do not cover all types of GLOF or are geographically constrained. Further, downstream impacts are rarely discussed. Previous inventories have relied on academic sources and have not been combined with existing inventories of glaciers and lakes. In this study, we present the first comprehensive inventory of GLOFs in HMA, including details on the time of their occurrence, processes of lake formation and drainage involved, and downstream impacts. We document 697 individual GLOFs that occurred between 1833 and 2022. Of these, 23 % were recurring events from just three ephemeral ice-dammed lakes. In combination, the documented events resulted in 6906 fatalities of which 906 can be attributed to 24 individual GLOF events, which is 3 times higher than a previous assessment for the region. The integration of previous inventories of glaciers and lakes within this database will inform future assessments of potential drivers of GLOFs, allowing more robust projections to be developed. The database and future, updated versions are traceable and version-controlled and can be directly incorporated into further analysis. The database is available at https://doi.org/10.5281/zenodo.7271187 (Steiner and Shrestha, 2023), while the code including a development version is available on GitHub.

“…The presence of ineffectiveness, corruption or political tensions in any of these bodies could result in inefficiency (Zheng et al, 2021) as observed in the 1941 Huaraz disaster (Carey, 2005). As the proximity of people to glacial lakes increases in HMA, it will be vital that local communities, governments, NGOs, and international research communities work together to prevent and mitigate damages and losses from GLOF, particularly where GLOF runout tracks cross international borders, as observed in the Gongbatongshaco GLOF in 2016 (Nie et al, 2018;Zhang et al, 2021) and by modelling of future potential GLOFs by Allen et al (2022). Currently, transboundary risk mitigation and disaster recovery is inescapably (and detrimentally) linked to global politics and finance.…”

Section: Implications For Early Warning Systemsmentioning

confidence: 99%

The rise of GLOF danger: trends, drivers and hotspots between 2000 and 2020

Taylor

Robinson

Dunning

et al. 2023

Preprint

Between 2000 and 2020, the potential for glacial lake outburst floods (GLOFs) and the exposure and vulnerability of downstream populations to them, have changed across the globe. The impact of these changes on the danger posed by GLOFs, as well as the relative importance of each factor, remains contentious, making the implementation of appropriate management and risk reduction strategies challenging. Here we show that globally, since 2000, the number of people exposed to GLOF impacts has increased by 3.2 million (27% increase), to a total of 15 million people as of 2020. The largest increase in GLOF danger occurred across the Andes, while only nine countries experienced a decrease in GLOF danger, most notably in Nepal and Kyrgyzstan. Importantly, contrary to the notion presented in current research, we find the changes in the threat from GLOFs have not been universally driven by either lake change, exposed population, or vulnerability; instead, the primary driver varies both at regional- and national-scales. Further, we show that vulnerability to GLOF impacts has declined almost everywhere, but this decline has been insufficient to offset the combined growth in the number and area of glacial lakes and downstream exposure. We highlight the Andes as a global hotspot for high, and rapidly increasing, contemporary GLOF danger, and suggest the region be targeted for further research. Critically, we show that mitigating GLOF impacts will require bespoke solutions depending on the relative impact of lake conditions, exposure and vulnerability on changing GLOF danger.