Introduction

Sikkim has physical features like rivers and mountains and has a very rugged topography and flat lands. The major river of Sikkim Tista originates from Cholamu Lake, it makes various tributaries along the way as it goes. Rangit is the major tributary of Tista which originates from Rathong glacier. No one can imagine that this innocuous-looking stream would transform into a thundering mighty river less than a hundred kilometers downstream. From an altitude of almost 5400 meters, the Tista plumes down in less than 80 kilometers to 1620 meters throughout about 100 kilometers.

The other major tributaries of Tista River are Zemu (chu) River, Lonak Chu, Lachung Chu, Talung Chu, and Bakcha Chu, Tista River is a snow-fed river. Sikkim’s rivers flow fast and furious because of their potential of generating thousands of megawatts of electricity number hydropower has nestled in the state.

Sikkim is one of the rainiest regions of India, Because of the mountainous region most of the parts of the state experience torrential rain during monsoon. But with the impact of climate change, rainfall pattern has become uneven. On 4th October 2023, there were heavy downpours which led to the Glacial Lake Outburst Flow due to the heavy flow Chungthang dam were burst leading to a more devastating situation for all the low-lying areas that lie along the river belt.  Detailed description of the incident is explained below.

Flash floods in Sikkim

On 4th October 2023, the picturesque Sikkim, nestled in the Himalayan foothills, the northeastern state of India experienced devastating flash floods. The tragedy was attributed to the GLOF from Lhonak Lake, which in turn, was set in motion by relentless heavy rains. The surge of water led to the catastrophic burst of the Chungthang dam, leaving destruction in its wake. This article delves into the sequence of events and their impact on North, East, and South Sikkim with far-reaching consequences of its residence.

Sikkim, with its fragile climatic condition, is a region vulnerable to climate change impacts. The incident started with the Glacial Lake Outburst Flow in Lhonak Lake which is situated in North Sikkim. This glacial lake, nestled at an altitude, accumulated excessive glacial meltwater due to a rise in temperature and heavy rainfall. Eventually, the immense pressure resulted in the Lhonak Lake outburst, releasing a colossal volume of water downstream.

Chungthang Dam Disaster

The surge from Lhonak Lake cascaded downstream towards Chungthang, a small town located in North Sikkim. The Chungthang Dam, a vital structure for the region’s water management could not withstand the sheer force of the unleased water. The dam’s breach unleashed a torrent of water, creating a deadly flash flood on its path. This unexpected disaster caught the region off guard resulting a severe consequence.

Impact on North, East, and South Sikkim

The flash floods wreaked havoc in North-East and East Sikkim, causing extensive damage to lives and property. The sudden rush of water inundated homes and settlements along its count leaving countless families displaced and their dwellings washed away. The loss of life and livelihood was heart-wrenching with many coming to terms with their shattered homes and communities.

 

 

 

Infrastructure in Ruins Flash Floods in Sikkim

The flash floods also inflicted massive damage on public infrastructure in the region. Many roads were damaged and nearly 14 bridges were washed away. As these are vital lifelines for remote areas in the hilly terrain, Apart from schools and buildings being damaged uncountably,

Conclusion

The flash floods in Sikkim on October 4, 2023, serve as a stark reminder of the destructive power of nature and the profound consequences of climate change. The triggering of the GLOF from Lhonak Lake, the subsequent bursting of the Chungthang dam, and the devastating flow of water have left an indelible mark on the people of North, East, and South Sikkim. It left the importance of preparedness and mitigation strategies for such vulnerable regions and the to address climate change is growing threats comprehension. The path to recovery and rebuilding will be long, but the resilience of the shines through way to stand together in the face of adversity.

 

 

Table: District-wise data of damage caused by flash floods 

District	No. of Population affected lives	Lives Lost	Missing	Houses Damaged	Rescued Person	Bridge collapsed.
Mangan	30300	04	23	568	850	18
Gangtok	20000	08	23	319	1025	03
Pakyong	30000	27	27	635	58	03
Namchi	8100	03	04	482	330	04

Source: Sikkim State Disaster Management Authority (SSDMA)