Glacial lake changes and the identification of potentially dangerous glacial lakes (PDGLs) under warming climate in the Dibang River Basin, Eastern Himalaya, India

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

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.

“…There have been a few attempts to study glacial lakes in this region [57][58][59], which also reveal similar trends of glacial lake expansion in the region and increasing GLOF hazard. Different studies have used various pre-determined thresholds such as A > 0.1 [61], and A > 0.2 km 2 [57] for selecting glacial lakes for hazard assessment in the Himalayas. We have selected a lower threshold value of A>0.05 km 2 in order to include much smaller lakes for hazard assessment in this study as smaller lakes have witnessed GLOF events in the past [27,28].…”

Section: Discussionmentioning

confidence: 99%

“…The present study attempted to provide a first order hazard scenario for GLOF in Shyok Catchment by taking into consideration nine key criteria found to be the most relevant with lake outburst susceptibility in the region. This must be kept in mind that lakes which have been attributed with medium and Low GLOF susceptibilities can also produce a GLOF event due to some extreme trigger such as a cloudburst or a heavy landslide into the lake [24,61,62]. Hence, this study only provides with a prioritization of glacial lakes in consideration to the GLOF hazard.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Understanding Glacial Lake Evolution and the Associated GLOF Hazard in Shyok Catchment of Upper Indus Basin

Rather

Ahmed

Bateni

et al. 2023

Preprint

As glaciers recede in response to global climate change, a significant growth of glacial lakes is being witnessed in the Himalayan region. Owing to their high elevations, rapid growth and mostly unstable dams constituting of loosely consolidated glacial moraine deposits, these lakes pose a significant threat in the form of Glacial Lake Outburst Floods (GLOFs). This study focused on studying the evolution of glacial lakes in Shyok catchment of Upper Indus basin, over a period of 30 years (1992 to 2022) and assessing their GLOF hazard levels. The Inventorization and Spatio-temporal change detection of the glacial lakes (A≥0.001 km2) was done using multi-temporal medium and high-resolution satellite imagery from the years 1992, 2002, 2012 and 2022. Besides, we have used Google Earth and Planet imagery, to validate the glacier and glacial lakes outlines. The GLOF hazard level assessment was carried out through a multi-criteria approach using Analytical Hierarchy Process AHP to classify the lakes into very-low, low, medium, high and very-high hazard categories. The results reveal a significant increase in the total number of glacial lakes from 143 in 1992 to 240 in 2022 as well as the total glacial lake area that increased from 8.45 km2 (± 0.02 km2) in 1992 to 13.26 km2 (± 0.04 km2) in 2022. Furthermore, out of 63 glacial lakes (A>0.05 km2) selected for the hazard assessment, 7 lakes were identified as very-high hazard lakes with GLOF susceptibility indices greater than 7.0 while 19 more lakes were classified as High-hazard lakes with GLOF susceptibilities in the range of 0.6 to 0.7. Most of these lakes are proglacial lakes and are close to their mother glaciers. The majority of these hazardous lakes have witnessed a high growth rate, which suggests that the GLOF hazard of these lakes is going to increase further in the future owing to the warming climatic trends. This study will act as a precursor to a more detailed and in-depth GLOF risk assessment of highly hazardous glacial lakes in the region and will help in developing mitigation strategies for any potential disasters in future.