2023 Sikkim flash floods
 | It has been suggested that this article be merged with 2023 Sikkim Flash Floods. (Discuss) Proposed since October 2023. |
| Date | 4 - 5 October 2023 |
|---|---|
| Location |
|
| Cause | Outburst of the South Lhonak lake due to heavy rainfall |
| Deaths | At least 40 |
| Property damage | 15 bridges, one hydroelectric dam destroyed |
On 4 October 2023, heavy rains caused the glacial South Lhonak lake in Sikkim, a state in northeastern India, to breach its banks, causing a glacial lake outburst flood.[1] The flood reached the Teesta III Dam at Chungthang at midnight, before its gates could be opened, destroying the dam in minutes.[2] Water levels downstream in the River Teesta rose by up to twenty feet, causing widespread damage.[3]
Course of events
Background
The South Lhonak lake is a moraine-dammed lake fed by the meltwater of the Lhonak glacier. It was first seen in CORONA satellite images from 1962 as a supraglacial lake. Landsat MSS images show that it became a separate lake by 1977, with a surface area of 17 hectares. In four decades, as the glacier retreated 1.9km, the lake swelled in size, covering nearly a hundred hectares by 2008.[4] 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.[5]
Sentinel-1A images from 28 September 2023 showed the lake covering an area of 167.4 hectares.[6]
The flood
In early October 2023, a cloudburst caused Sikkim to receive more than double its normal rainfall;[7] between 3 and 4 October alone, the state received five times the usual precipitation.[1] The South Lhonak burst its shores, causing a flash flood. Satellite images from the 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 1200MW hydroelectric powerhouse, which went underwater.[2]
Water levels downstream in the River Teesta subsequently rose by fifteen to twenty feet, inundating many areas in Mangan, Gangtok, Pakyong, and Namchi districts in Sikkim, and Kalimpong, Cooch Behar, Jalpaiguri and Darjeeling districts in West Bengal.[8] The flood also went onwards to Bangladesh, where it affected hundreds of villages along the Teesta River and Char areas.[9]
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 collapsed.[1] 3,000 tourists were stranded across the state.[10]
Relief operations
The government of Sikkim declared the flood a disaster, and the Indian central government released ₹48 crore ($5.76 million)[a] in disaster relief funds.[8][11] The National Disaster Response Force and the Indian Army are involved in the ongoing relief operations.[11] 2,400 people were evacuated from flood-hit areas, and 7,600 others were in relief camps.[7] 10,000 more were evacuated in West Bengal.[10]
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.[12]
Casualties
At least 40 people were killed and 22 injured, while 75 were reported missing as of 6 October.[7] Of the missing were 23 Indian Army personnel, of whom one was subsequently rescued.[13] A body of another soldier was found floating in the Teesta in Nilphamari, Bangladesh. The Border Guard Bangladesh handed over the soldier's body to the Indian officials through a flag meeting.[9] 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.[7]
Notes
- ^ Based of an exchange rate of 1 USD = 83.26 INR as on 6 October 2023
References
- ^ a b c Choudhury, Subrata Nag; Hussain, Zarir (4 October 2023). "Floods in India's Sikkim state leave 10 dead, 82 missing". Reuters. Retrieved 4 October 2023.
- ^ a b "Sikkim dam washed away in 10 minutes after flash flood: Official". Hindustan Times. 4 October 2023. Retrieved 4 October 2023.
- ^ "8 dead, 22 army men among 48 missing as flash flood wreaks havoc in Sikkim". The Tribune India. 4 October 2023. Retrieved 4 October 2023.
- ^ Babu Govindha Raj, K.; Remya, S. N.; Vinod Kumar, K. (10 February 2013). "Remote sensing-based hazard assessment of glacial lakes in Sikkim Himalaya". Current Science. 104 (3): 359–364 – via JSTOR.
- ^ Singh, Jyoti (2018-09-26). "Glacial lake flood keeps disaster managers on toes in Sikkim". BusinessLine. Retrieved 2023-10-06.
- ^ "Sikkim flash floods | Over half the area drained: ISRO satellite images show before, after of South Lhonak lake". The Indian Express. 2023-10-05. Retrieved 2023-10-06.
- ^ a b c d Choudhury, Subrata Nag; Ahmed, Aftab (2023-10-06). "Death toll rises to 40 after glacial lake flooding in Indian Himalayas, dozens still missing". Reuters. Retrieved 2023-10-06.
- ^ a b "Sikkim flood | 10 dead, 22 army men among 82 missing as flash flood wreaks havoc; PM Modi dials CM Tamang". The Hindu. 2023-10-04. ISSN 0971-751X. Retrieved 2023-10-06.
- ^ a b "Indian soldier's body found in Teesta handed over to BSF". Dhaka Tribune. 6 October 2023. Retrieved 6 October 2023.
- ^ a b "Sikkim: Race against time to save 102 missing in India floods". BBC News. 2023-10-05. Retrieved 2023-10-06.
- ^ a b "Sikkim flash floods: Centre approves release of Rs 44.8 crore in funds". The Economic Times. 2023-10-06. ISSN 0013-0389. Retrieved 2023-10-06.
- ^ "Sikkim floods: NDRF faces great unknown in bid to save 14 trapped in tunnels". Hindustan Times. 2023-10-06. Retrieved 2023-10-06.
- ^ "Sikkim Flash Floods Updates: One out of 23 missing Army personnel rescued". Hindustan Times. 4 October 2023. Archived from the original on 4 October 2023. Retrieved 4 October 2023.
