A sudden cloudburst in North Sikkim has led to flash floods in the Teesta River, resulting in the disappearance of 23 Army personnel whose vehicles were swept away by the raging floodwaters.

The flash floods were a direct consequence of a cloudburst over Lhonak Lake in North Sikkim.

On Tuesday night, a flash flood in the Teesta River, specifically in Sikkim’s Lachen valley, left 23 Army personnel missing, according to officials.

The flash flood was the result of an abrupt cloudburst that occurred over Lhonak Lake in North Sikkim. This event led to a sudden surge in water levels in the Teesta River. The situation was further exacerbated when water was released from the Chungthang dam, causing water levels to rise up to 15-20 feet downstream.

The Sikkim government released a statement, saying, “The Glacial Lake Outburst Flood (GLOF) in portions of Lhonak Lake, Mangan district, which caused the rise of water levels with very high velocities downstream along the Teesta River Basin in the early hours of October 4, 2023, has caused severe damage in Mangan, Gangtok, Pakyong, and Namchi districts. The lake outburst in portions of Lhonak Lake in North Sikkim caused a rise in water levels with very high velocities near about 15m/sec, crossed the CWC Melli site measuring 227 m, near about 3m above Danger Level, at 6 AM.”

Army vehicles parked near Singtam at Bardang were swept away by the powerful floodwaters. Search and rescue operations are currently underway to locate the missing personnel.

In addition to the disappearance of Army personnel, the flash flood has caused significant damage to several Army installations along the Lachen valley. Authorities are in the process of assessing the full extent of the damage.

The overflowing Teesta River led to the collapse of the Singtham footbridge. Moreover, several sections of National Highway 10, connecting West Bengal to Sikkim, were washed away, rendering many roads blocked or impassable in Namchi following the flash flood.

The State Disaster Management Authority (SSDMA) reported that Chungthang in Mangan district became inaccessible after the Toong bridge collapsed. Several homes in Phidang and Dikchu were washed away, and six individuals have been reported missing.

In Gangtok, four individuals sustained injuries due to rain-related incidents and were subsequently hospitalized for treatment. Over 500 people have been evacuated and relocated to relief camps in Namchi district.

The Sikkim government has issued a high alert across the state, urging people to steer clear of the Teesta River. The Jalpaiguri administration in West Bengal has initiated evacuation procedures in the lower catchment area of the river as a precautionary measure.

The India Meteorological Department has issued an orange alert, warning of heavy rain in Gangtok, Gyalshing, Pakyong, and Soreng districts for the next two days. Additionally, a red alert for extremely heavy rainfall has been issued for Mangan and Namchi districts.

West Bengal Chief Minister Mamata Banerjee has called on residents in the state’s northern regions to maintain maximum vigilance and has assured that “all steps have been taken to evacuate people in the districts of Kalimpong, Darjeeling, and Jalpaiguri to safer places.”