The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade

Ashim Sattar; Kristen L. Cook; Shashi Kant Rai; Etienne Berthier; Simon Allen; Sonam Rinzin; Maximillian Van Wyk de Vries; Wilfried Haeberli; Pradeep Kushwaha; Dan H. Shugar; Adam Emmer; Umesh K. Haritashya; Holger Frey; Praful Rao; Kori Sanjay Kumar Gurudin; Prabhakar Rai; Rajeev Rajak; Faruk Hossain; Christian Huggel; Martin Mergili; Mohd. Farooq Azam; Simon Gascoin; Jonathan L. Carrivick; Louie Elliot Bell; Rakesh Kumar Ranjan; Irfan Rashid; Anil. V. Kulkarni; Dave Petley; Wolfgang Schwanghart; C. Scott Watson; Nazimul Islam; Moushumi Das Gupta; Stuart N. Lane; Shahid Younis Bhat

doi:10.1126/science.ads2659

The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade

Ashim Sattar^*
, Kristen L. Cook
, Shashi Kant Rai
, Etienne Berthier
, Simon Allen
, Sonam Rinzin
, Maximillian Van Wyk de Vries
, Wilfried Haeberli
, Pradeep Kushwaha
, Dan H. Shugar
, Adam Emmer
, Umesh K. Haritashya
, Holger Frey
, Praful Rao
, Kori Sanjay Kumar Gurudin
, Prabhakar Rai
, Rajeev Rajak
, Faruk Hossain
, Christian Huggel
, Martin Mergili

Mohd. Farooq Azam, Simon Gascoin, Jonathan L. Carrivick, Louie Elliot Bell, Rakesh Kumar Ranjan, Irfan Rashid, Anil. V. Kulkarni, Dave Petley, Wolfgang Schwanghart, C. Scott Watson, Nazimul Islam, Moushumi Das Gupta, Stuart N. Lane, Shahid Younis Bhat

^*Corresponding author for this work

Geography

Research output: Contribution to journal › Article › peer-review

Abstract

On 3 October 2023, a multihazard cascade in the Sikkim Himalaya, India, was triggered by 14.7 million m³ of frozen lateral moraine collapsing into South Lhonak Lake, generating an ~20 m tsunami-like impact wave, breaching the moraine, and draining ~50 million m³ of water. The ensuing Glacial Lake Outburst Flood (GLOF) eroded ~270 million m³ of sediment, which overwhelmed infrastructure, including hydropower installations along the Teesta River. The physical scale and human and economic impact of this event prompts urgent reflection on the role of climate change and human activities in exacerbating such disasters. Insights into multihazard evolution are pivotal for informing policy development, enhancing Early Warning Systems (EWS), and spurring paradigm shifts in GLOF risk management strategies in the Himalaya and other mountain environments.

Original language	English
Article number	eads2659
Journal	Science
Early online date	30 Jan 2025
DOIs	https://doi.org/10.1126/science.ads2659
Publication status	E-pub ahead of print - 30 Jan 2025

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SDG 13 Climate Action

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Sattar, A., Cook, K. L., Rai, S. K., Berthier, E., Allen, S., Rinzin, S., Van Wyk de Vries, M., Haeberli, W., Kushwaha, P., Shugar, D. H., Emmer, A., Haritashya, U. K., Frey, H., Rao, P., Gurudin, K. S. K., Rai, P., Rajak, R., Hossain, F., Huggel, C., ... Bhat, S. Y. (2025). The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade. Science, Article eads2659. Advance online publication. https://doi.org/10.1126/science.ads2659

@article{d4a07abc9aa7416f83b87b90d2a278fd,

title = "The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade",

abstract = "On 3 October 2023, a multihazard cascade in the Sikkim Himalaya, India, was triggered by 14.7 million m3 of frozen lateral moraine collapsing into South Lhonak Lake, generating an \textasciitilde{}20 m tsunami-like impact wave, breaching the moraine, and draining \textasciitilde{}50 million m3 of water. The ensuing Glacial Lake Outburst Flood (GLOF) eroded \textasciitilde{}270 million m3 of sediment, which overwhelmed infrastructure, including hydropower installations along the Teesta River. The physical scale and human and economic impact of this event prompts urgent reflection on the role of climate change and human activities in exacerbating such disasters. Insights into multihazard evolution are pivotal for informing policy development, enhancing Early Warning Systems (EWS), and spurring paradigm shifts in GLOF risk management strategies in the Himalaya and other mountain environments. ",

author = "Ashim Sattar and Cook, \{Kristen L.\} and Rai, \{Shashi Kant\} and Etienne Berthier and Simon Allen and Sonam Rinzin and \{Van Wyk de Vries\}, Maximillian and Wilfried Haeberli and Pradeep Kushwaha and Shugar, \{Dan H.\} and Adam Emmer and Haritashya, \{Umesh K.\} and Holger Frey and Praful Rao and Gurudin, \{Kori Sanjay Kumar\} and Prabhakar Rai and Rajeev Rajak and Faruk Hossain and Christian Huggel and Martin Mergili and Azam, \{Mohd. Farooq\} and Simon Gascoin and Carrivick, \{Jonathan L.\} and Bell, \{Louie Elliot\} and Ranjan, \{Rakesh Kumar\} and Irfan Rashid and Kulkarni, \{Anil. V.\} and Dave Petley and Wolfgang Schwanghart and Watson, \{C. Scott\} and Nazimul Islam and Gupta, \{Moushumi Das\} and Lane, \{Stuart N.\} and Bhat, \{Shahid Younis\}",

year = "2025",

month = jan,

day = "30",

doi = "10.1126/science.ads2659",

language = "English",

journal = "Science",

issn = "0036-8075",

publisher = "American Association for the Advancement of Science",

}

Sattar, A, Cook, KL, Rai, SK, Berthier, E, Allen, S, Rinzin, S, Van Wyk de Vries, M, Haeberli, W, Kushwaha, P, Shugar, DH, Emmer, A, Haritashya, UK, Frey, H, Rao, P, Gurudin, KSK, Rai, P, Rajak, R, Hossain, F, Huggel, C, Mergili, M, Azam, MF, Gascoin, S, Carrivick, JL, Bell, LE, Ranjan, RK, Rashid, I, Kulkarni, AV, Petley, D, Schwanghart, W, Watson, CS, Islam, N, Gupta, MD, Lane, SN & Bhat, SY 2025, 'The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade', Science. https://doi.org/10.1126/science.ads2659

TY - JOUR

T1 - The Sikkim flood of October 2023

T2 - Drivers, causes and impacts of a multihazard cascade

AU - Sattar, Ashim

AU - Cook, Kristen L.

AU - Rai, Shashi Kant

AU - Berthier, Etienne

AU - Allen, Simon

AU - Rinzin, Sonam

AU - Van Wyk de Vries, Maximillian

AU - Haeberli, Wilfried

AU - Kushwaha, Pradeep

AU - Shugar, Dan H.

AU - Emmer, Adam

AU - Haritashya, Umesh K.

AU - Frey, Holger

AU - Rao, Praful

AU - Gurudin, Kori Sanjay Kumar

AU - Rai, Prabhakar

AU - Rajak, Rajeev

AU - Hossain, Faruk

AU - Huggel, Christian

AU - Mergili, Martin

AU - Azam, Mohd. Farooq

AU - Gascoin, Simon

AU - Carrivick, Jonathan L.

AU - Bell, Louie Elliot

AU - Ranjan, Rakesh Kumar

AU - Rashid, Irfan

AU - Kulkarni, Anil. V.

AU - Petley, Dave

AU - Schwanghart, Wolfgang

AU - Watson, C. Scott

AU - Islam, Nazimul

AU - Gupta, Moushumi Das

AU - Lane, Stuart N.

AU - Bhat, Shahid Younis

PY - 2025/1/30

Y1 - 2025/1/30

N2 - On 3 October 2023, a multihazard cascade in the Sikkim Himalaya, India, was triggered by 14.7 million m3 of frozen lateral moraine collapsing into South Lhonak Lake, generating an ~20 m tsunami-like impact wave, breaching the moraine, and draining ~50 million m3 of water. The ensuing Glacial Lake Outburst Flood (GLOF) eroded ~270 million m3 of sediment, which overwhelmed infrastructure, including hydropower installations along the Teesta River. The physical scale and human and economic impact of this event prompts urgent reflection on the role of climate change and human activities in exacerbating such disasters. Insights into multihazard evolution are pivotal for informing policy development, enhancing Early Warning Systems (EWS), and spurring paradigm shifts in GLOF risk management strategies in the Himalaya and other mountain environments.

AB - On 3 October 2023, a multihazard cascade in the Sikkim Himalaya, India, was triggered by 14.7 million m3 of frozen lateral moraine collapsing into South Lhonak Lake, generating an ~20 m tsunami-like impact wave, breaching the moraine, and draining ~50 million m3 of water. The ensuing Glacial Lake Outburst Flood (GLOF) eroded ~270 million m3 of sediment, which overwhelmed infrastructure, including hydropower installations along the Teesta River. The physical scale and human and economic impact of this event prompts urgent reflection on the role of climate change and human activities in exacerbating such disasters. Insights into multihazard evolution are pivotal for informing policy development, enhancing Early Warning Systems (EWS), and spurring paradigm shifts in GLOF risk management strategies in the Himalaya and other mountain environments.

U2 - 10.1126/science.ads2659

DO - 10.1126/science.ads2659

M3 - Article

SN - 0036-8075

JO - Science

JF - Science

M1 - eads2659

ER -

The Sikkim flood of October 2023: Drivers, causes and impacts of a multihazard cascade

Abstract

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