The Lhonak Lake in Sikkim state burst its banks on Wednesday causing major flooding, which authorities said had impacted the lives of 22,000 people. It is the latest deadly weather event in South Asia’s mountains being blamed on climate change.

The weather department said Sikkim received 101 mm (4 inches) of rain in the first five days of October, more than double normal levels, triggering floods worse than one in October 1968 in which an estimated 1,000 people were killed.

The department has predicted heavy rain over the next three days in parts of Sikkim and neighbouring states.

The latest flooding was exacerbated by water released from state-run NHPC’s Teesta V dam, local officials said. Four of the dam’s gates had been washed away and it was not clear why they had not been opened in time, a government source told Reuters.

As of early Thursday, the state disaster management agency said 26 people had been injured and 102 were missing, 22 of whom were army personnel. Eleven bridges had been washed away, hampering rescue operations which were already affected by heavy rainfall.

Authorities in neighbouring Bangladesh were on alert with a state-run water development board official warning that five districts in the northern part of the country could be inundated with a rise in the level of the Teesta river, which enters Bangladesh downstream of Sikkim.

“Continued efforts are on to dig out vehicles submerged under the slush at Burdang near Singtam. The search for the missing persons is now focusing in the areas downstream of Teesta river,” an Indian defence spokesperson said.

FUEL SCARCE, FOOD AVAILABLE

Video footage from the ANI news agency, in which Reuters has a minority stake, showed flood waters surging into built-up areas where several houses collapsed. Army bases and other facilities were damaged and vehicles submerged.

Satellite imagery showed that nearly two-third of the lake seems to have been drained.

Sikkim, a small state of about 650,000 people which is wedged in the mountains between Nepal, Bhutan and China, was cut off from Siliguri in the neighbouring state of West Bengal as the main highway had collapsed.

State lawmaker G.T. Dhungel told Reuters that petrol and diesel had become scarce in state capital Gangtok but food was readily available.

A cloudburst on Wednesday dropped a huge amount of rain over a short period on the Lhonak Lake, about 150 km (90 miles) north of Gangtok near the border with China, triggering flash floods down the Teesta valley.

A 2020 report by India’s National Disaster Management Agency said glacial lakes are growing and pose a potentially large risk to downstream infrastructure and life as glaciers in the Himalayas are melting due to climate change.

“Sadly, this is the latest in a series of deadly flash floods that ricocheted across the Hindu Kush-Himalayan region this monsoon, bringing the reality of this region’s extreme vulnerability to climate change all too vividly alive,” said Pema Gyamtsho, director-general of the Nepal-based International Centre for Integrated Mountain Development.

Other mountainous areas of India, as well as parts of neighbouring Pakistan and Nepal, have been hit by torrential rains, flooding and landslides in recent months, killing scores of people.

A report by India’s National Remote Sensing Centre scientists a decade ago had warned the chances of the lake bursting its banks was “very high” at 42%.

By Subrata Nag Choudhury and Jatindra Dash

(Reporting by Subrata Nag Choudhury in Kolkata, Jatindra Dash in Bhubaneswar, Tanvi Mehta, and Krishn Kaushik in New Delhi, additional reporting by and Sarita Chaganti Singh, Ruma Paul and Rajendra Jadhav; editing by Robert Birsel, Michael Perry, YP Rajesh and Kim Coghill)