A major landslide in North Sikkim's Mangan district has partially obstructed the flow of the Teesta and Chyakoong rivers, prompting authorities to intensify monitoring of the river system and warn people to stay away from riverbanks.

The landslide occurred during the night of September 5–6 in the Naga Forest area near the Theng Tunnel, where a large section of hillside along the newly cut Naga–Tosa Road collapsed close to the confluence of the two rivers.

River flow temporarily obstructed

The landslide sent a substantial amount of debris into the river channels, temporarily restricting the flow of both rivers. Water accumulated behind the debris, raising concerns about the possibility of a sudden downstream surge.

However, authorities said the Teesta River's flow had returned to normal after the natural channel opened further. A subsequent assessment by Mangan district officials found that the risk of a sudden flash release had significantly decreased and that the overall situation was stable.

Water levels at the Sankalang and Phidang monitoring points were reported to be normal, although the water had become muddy.

No casualties reported

No deaths or injuries have been reported in connection with the landslide so far.

Officials from the Chungthang police and Theng check post have been maintaining continuous surveillance of the affected area, while district disaster management teams are assessing possible damage to infrastructure and property.

The administration has also directed authorities in downstream areas to remain prepared and immediately report any significant change in river levels.

Residents urged to remain cautious

Although the immediate threat has reduced, authorities have advised residents along the downstream Teesta belt to remain vigilant.

People have been asked to avoid approaching riverbanks and fast-flowing water and to move temporarily to safer, higher ground if conditions deteriorate. Officials have also urged the public to rely on official information rather than unverified claims circulating on social media.

The incident has generated heightened concern because of the region's history of severe flooding, including the devastating 2023 Teesta flash flood, as well as recent flood and landslide disasters in the Himalayan region.

Tourists stranded after road disruption

The landslide also disrupted road connectivity in the affected area, leaving some tourists stranded.

The Indian Army assisted in moving stranded tourists toward Gangtok after roads were blocked by debris.

Authorities continue to monitor both the landslide site and the Teesta river corridor around the clock.

Situation remains under close watch

The Mangan district administration has said it will continue monitoring slope stability and river levels until the affected stretch is fully assessed and cleared.

While the current river flow is considered normal and the immediate downstream danger has decreased, officials are maintaining precautionary measures because further rainfall could affect the unstable terrain and river conditions.

HamroBichar will continue to follow developments in North Sikkim and provide verified updates on the landslide, river conditions and any changes in the downstream risk.

Tags: Sikkim, North Sikkim, Mangan, Teesta River, Chyakoong River, Landslide, India, Flood Risk, Theng Tunnel, Gangtok, Himalayan Disaster

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Landslide Partially Blocks Teesta and Chyakoong Rivers in North Sikkim