Preprints
https://doi.org/10.5194/egusphere-2024-565
https://doi.org/10.5194/egusphere-2024-565
21 Mar 2024
 | 21 Mar 2024
Status: this preprint is open for discussion.

Predicting the Risk of Glacial Lake Outburst Floods in Karakorum

Nazir Ahmed Bazai, Paul A. Carling, Peng Cui, Wang Hao, Zhang Guotao, Liu Dingzhu, and Javed Hassan

Abstract. Glacier snouts respond to climate change by forming proglacial meltwater lakes, thereby influencing glacier mass balance and leading to advancements and surges. The positive feedback of climate change results in more frequent ice-dammed glacial lake outburst floods (GLOFs) in the Karakorum and surrounding regions, often facilitated by englacial conduits. However, the complex and multi-factor processes of conduit development are challenging to measure. Determining the lake depths that might trigger GLOFs and the numerical model specifications for breaching are still being determined. Empirical estimates of lake volumes, along with field-based monitoring of lake levels and depths and the assessment of GLOF risks, enable warnings and damage mitigation. Using historical data, remote sensing techniques, high-resolution imagery, cross-correlation feature-tracking, and field-based data, we identified the processes of lake formation, drainage timing, and triggering depth. We developed empirical approaches to determine lake volume and trigger water pressure leading to a GLOF. The correlation of glacier surge and lake volume reveals that glacier surge velocity plays a crucial role in lake formation and controlling the size and volume of the lake. Lake volume estimation involves geometric considerations of the lake basin shape. A GLOF becomes likely when the lake's non-dimensional depth (n’) exceeds 0.60, correlating with a typical water pressure on the dam face of 510 kPa. Additionally, we identified the critical risk zone of lakes, where all lake outburst floods occur, as the point where the lake volume reaches or exceeds 60 % of its capacity. These field-based and empirical findings not only offer valuable insights for early warning procedures in the Karakorum but also suggest that similar approaches can be effectively applied to other mountain environments worldwide where GLOFs pose a hazard.

Nazir Ahmed Bazai, Paul A. Carling, Peng Cui, Wang Hao, Zhang Guotao, Liu Dingzhu, and Javed Hassan

Status: open (until 02 May 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on egusphere-2024-565', Taigang Zhang, 25 Mar 2024 reply
    • AC1: 'Reply on CC1', Nazir Ahmed Bazai, 25 Mar 2024 reply
  • RC1: 'Comment on egusphere-2024-565', Wilhelm Furian, 28 Mar 2024 reply
Nazir Ahmed Bazai, Paul A. Carling, Peng Cui, Wang Hao, Zhang Guotao, Liu Dingzhu, and Javed Hassan
Nazir Ahmed Bazai, Paul A. Carling, Peng Cui, Wang Hao, Zhang Guotao, Liu Dingzhu, and Javed Hassan

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Short summary
Research on ice-dammed glacier lake outburst floods (GLOFs) tackles the growing global threat. Identifying field-based key factors and promoting and establishing a 95 % accurate empirical model unveils the relationship between lake volume and glacier surge, which controls lake size and level. Critical findings, including GLOF likelihood, triggering depth, and risk zones, provide insights for global early warning systems, highlighting the need to address cryospheric risks and protect communities.