Viki at 16:34, 6 October 2023

2023-10-06T16:34:25Z

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{{Short description|Natural disaster in Northeast India}}
{{Merge|2023 Sikkim Flash Floods|discuss=Talk:2023 India flash floods#Proposed merge of 2023 Sikkim flash floods with 2023 India flash floods|date=October 2023}}
{{Infobox flood
| name = 2023 Sikkim flash floods
| duration = 4 - 5 October 2023
| total damages = 15 bridges, one hydroelectric dam destroyed
| total fatalities = At least 40
| areas affected = {{ubl|'''[[Sikkim]] districts'''|[[Mangan district|Mangan]], [[Gangtok district|Gangtok]], [[Pakyong district|Pakyong]], and [[Namchi district|Namchi]]|'''[[West Bengal]] districts'''|[[Cooch Behar district|Cooch Behar]], [[Jalpaiguri district|Jalpaiguri]], [[Darjeeling district|Darjeeling]], and [[Kalimpong district|Kalimpong]]}}
| cause = [[Glacial lake outburst flood|Outburst]] of the [[South Lhonak lake]] due to heavy rainfall
}}
On 4 October 2023, heavy rains caused the glacial [[South Lhonak lake]] in [[Sikkim]], a [[States and union territories of India|state]] in [[Northeast India|northeastern]] [[India]], to breach its banks, causing a [[glacial lake outburst flood]].<ref name=":0">{{Cite news |last=Choudhury |first=Subrata Nag |last2=Hussain |first2=Zarir |date=4 October 2023 |title=Floods in India's Sikkim state leave 10 dead, 82 missing |language=en |work=Reuters |url=https://www.reuters.com/world/india/nearly-two-dozen-indian-troops-missing-after-flash-flood-ani-2023-10-04/ |access-date=4 October 2023}}</ref> The flood reached the [[Teesta Barrage|Teesta III Dam]] at [[Chungthang]] at midnight, before its gates could be opened, destroying the dam in minutes.<ref name=":1">{{Cite web |date=4 October 2023 |title=Sikkim dam washed away in 10 minutes after flash flood: Official |url=https://www.hindustantimes.com/cities/others/sikkims-biggest-hydro-project-suffers-massive-damage-in-flash-flood-101696420752235.html |access-date=4 October 2023 |website=Hindustan Times |language=en}}</ref> Water levels downstream in the [[River Teesta]] rose by up to twenty feet, causing widespread damage.<ref>{{Cite news |date=4 October 2023 |title=8 dead, 22 army men among 48 missing as flash flood wreaks havoc in Sikkim |work=[[The Tribune India]] |url=https://www.tribuneindia.com/news/india/lake-burst-at-sikkims-chungthang-flash-flood-alert-as-teesta-river-water-levels-rise-550329 |access-date=4 October 2023}}</ref>

==Course of events==
===Background===
The South Lhonak Lake is a [[moraine-dammed lake]] fed by the meltwater of the [[Lonak Glacier|Lhonak glacier]]. It was first seen in [[CORONA (satellite)|CORONA]] satellite images from 1962 as a [[supraglacial lake]]. [[Landsat 2|Landsat MSS]] images show that it became a separate lake by 1977, with a surface area of 17 [[Hectare|hectares]]. In four decades, as the glacier [[Retreat of glaciers since 1850|retreated]] 1.9km, the lake swelled in size, covering nearly a hundred hectares by 2008.<ref>{{Cite journal |last=Babu Govindha Raj |first=K. |last2=Remya |first2=S. N. |last3=Vinod Kumar |first3=K. |date=10 February 2013 |title=Remote sensing-based hazard assessment of glacial lakes in Sikkim Himalaya |url=https://www.jstor.org/stable/24089638 |journal=[[Current Science]] |volume=104 |issue=3 |pages=359-364 |via=JSTOR}}</ref> It was identified as potentially being at risk of causing glacial outburst floods, and in 2018 pipelines were carried up by [[yak]] and installed to pump water out of it.<ref>{{Cite web |last=Singh |first=Jyoti |date=2018-09-26 |title=Glacial lake flood keeps disaster managers on toes in Sikkim |url=https://www.thehindubusinessline.com/news/science/glacial-lake-flood-keeps-disaster-managers-on-toes-in-sikkim/article25048865.ece |access-date=2023-10-06 |website=BusinessLine |language=en}}</ref>

[[Sentinel-1A]] images from 28 September 2023 showed the lake covering an area of 167.4 hectares.<ref>{{Cite web |date=2023-10-05 |title=Sikkim flash floods {{!}} Over half the area drained: ISRO satellite images show before, after of South Lhonak lake |url=https://indianexpress.com/article/india/sikkim-flash-floods-south-lhonak-lake-before-after-satellite-image-8969255/ |access-date=2023-10-06 |website=The Indian Express |language=en}}</ref>

===The flood===
In early October 2023, a cloudburst caused Sikkim to receive more than double its normal rainfall;<ref name=":2" /> between 3 and 4 October alone, the state received five times the usual precipitation.<ref name=":0" /> The South Lhonak burst its shores, causing a flash flood. Satellite images from the [[ISRO|Indian Space Research Organisation]]'s [[RISAT-1A]] show that the lake's surface area shrunk by more than a hundred hectares. Based on a warning from the [[Indo-Tibetan Border Police]] at midnight, the operators of the Teesta III Dam at Chungthang rushed to open the dam's gates, but were too late; the flood quickly destroyed the dam, as well as the bridge to its 1200[[MegaWatt|MW]] hydroelectric powerhouse, which went underwater.<ref name=":1" />

Water levels downstream in the River Teesta subsequently rose by fifteen to twenty feet, inundating many areas in [[Mangan district|Mangan]], [[Gangtok district|Gangtok]], [[Pakyong district|Pakyong]], and [[Namchi district|Namchi]] districts in Sikkim, and [[Kalimpong district|Kalimpong]], [[Cooch Behar district|Cooch Behar]], [[Jalpaiguri district|Jalpaiguri]] and [[Darjeeling district|Darjeeling]] districts in West Bengal.<ref name=":3">{{Cite news |last= |date=2023-10-04 |title=Sikkim flood {{!}} 10 dead, 22 army men among 82 missing as flash flood wreaks havoc; PM Modi dials CM Tamang |language=en-IN |work=The Hindu |url=https://www.thehindu.com/news/national/other-states/several-dead-and-missing-as-flash-flood-wreaks-havoc-in-sikkim-pm-modi-dials-cm/article67382079.ece |access-date=2023-10-06 |issn=0971-751X}}</ref> The flood also went onwards to Bangladesh, where it affected hundreds of villages along the Teesta River and Char areas.<ref name="Indian soldier’s body found in Teesta handed over to BSF" />

Fifteen bridges across the state were washed away, and the north of the state, including the capital [[Gangtok]], was cut off from the rest of India as parts of [[National Highway 10 (India)|National Highway 10]] collapsed.<ref name=":0" /> 3,000 tourists were stranded across the state.<ref name=":4">{{Cite news |date=2023-10-05 |title=Sikkim: Race against time to save 102 missing in India floods |language=en-GB |work=BBC News |url=https://www.bbc.com/news/business-66997995 |access-date=2023-10-06}}</ref>

==Relief operations==
The government of Sikkim declared the flood a disaster, and the Indian central government released [[Indian rupee|₹]]48 crore ([[United States dollar|$]]5.76 million){{efn|Based on an exchange rate of 1 USD <nowiki>=</nowiki> 83.26 INR as on 6 October 2023}} in disaster relief funds.<ref name=":3" /><ref name=":5">{{Cite news |date=2023-10-06 |title=Sikkim flash floods: Centre approves release of Rs 44.8 crore in funds |work=The Economic Times |url=https://economictimes.indiatimes.com/news/india/sikkim-flash-floods-centre-approves-release-of-rs-44-8-crore-in-funds/articleshow/104204325.cms?from=mdr |access-date=2023-10-06 |issn=0013-0389}}</ref> The [[National Disaster Response Force]] and the [[Indian Army]] are involved in the ongoing relief operations.<ref name=":5" /> 2,400 people were evacuated from flood-hit areas, and 7,600 others were in relief camps.<ref name=":2" /> 10,000 more were evacuated in West Bengal.<ref name=":4" />

Fourteen people were believed to be trapped inside the tunnels of the destroyed Teesta III Dam; a 60-strong team of the NDRF - including scuba divers - was assembled to rescue them.<ref>{{Cite web |date=2023-10-06 |title=Sikkim floods: NDRF faces great unknown in bid to save 14 trapped in tunnels |url=https://www.hindustantimes.com/india-news/sikkim-floods-ndrf-faces-great-unknown-in-bid-to-save-14-trapped-in-tunnels-101696533026443.html |access-date=2023-10-06 |website=Hindustan Times |language=en}}</ref>

==Casualties==
At least 40 people were killed and 22 injured, while 75 were reported missing as of 6 October.<ref name=":2">{{Cite news |last=Choudhury |first=Subrata Nag |last2=Ahmed |first2=Aftab |date=2023-10-06 |title=Death toll rises to 40 after glacial lake flooding in Indian Himalayas, dozens still missing |language=en |work=Reuters |url=https://www.reuters.com/world/india/least-40-killed-after-glacial-lake-flooding-indian-himalayas-officials-2023-10-06/ |access-date=2023-10-06}}</ref> Of the missing were 23 [[Indian Army]] personnel, of whom seven were subsequently found dead and one rescued alive.<ref>{{Cite web |date=4 October 2023 |title=Sikkim Flash Floods Updates: One out of 23 missing Army personnel rescued |url=https://www.hindustantimes.com/india-news/flash-flood-alert-sikkim-teesta-river-cloudburst-live-updates-4th-october-2023-101696390912870.html |url-status=dead |archive-url=https://web.archive.org/web/20231004185500/https://www.hindustantimes.com/india-news/flash-flood-alert-sikkim-teesta-river-cloudburst-live-updates-4th-october-2023-101696390912870.html |archive-date=4 October 2023 |access-date=4 October 2023 |website=Hindustan Times |language=en}}</ref><ref>{{Cite web |date=2023-10-06 |title=Sikkim flood: Death toll rises to 25; 'explosive, firearms' warning issued |url=https://www.hindustantimes.com/india-news/sikkim-flood-death-toll-rises-to-22-army-issues-explosive-firearms-warning-101696587365494.html |access-date=2023-10-06 |website=Hindustan Times |language=en}}</ref> One of the dead soldiers was found floating in the Teesta in [[Nilphamari]], [[Bangladesh]]; the [[Border Guard Bangladesh]] handed over the body to the Indian officials through a flag meeting.<ref name="Indian soldier’s body found in Teesta handed over to BSF">{{cite web |title=Indian soldier’s body found in Teesta handed over to BSF
|url=https://www.dhakatribune.com/amp/bangladesh/nation/327225/indian-soldier%E2%80%99s-body-found-in-teesta-handed-over |website=Dhaka Tribune |date=6 October 2023 |access-date=6 October 2023}}</ref> One child was killed and six injured in the neighbouring state of [[West Bengal]] when a mortar shell carried downstream from Sikkim exploded after being picked up by locals.<ref name=":2" />

==Notes==
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==References==
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{{DEFAULTSORT:Sikkim flash floods, 2023}}
[[Category:2023 disasters in India]]
[[Category:2023 floods in Asia]]
[[Category:2020s in Sikkim|Floods]]
[[Category:2020s in West Bengal]]
[[Category:October 2023 events in India]]
[[Category:Disasters in Sikkim|2023 floods]]
[[Category:Disasters in West Bengal]]
[[Category:Floods in India]]

2023 Sikkim flash floods - Revision history

Viki at 16:34, 6 October 2023