An alarm could have gone out for the glacial lake burst in the Himalayas if an early warning system were installed in the Lhonak Lake last year, but work on the project was delayed and only began in September — too late for the Sikkim flash floods that killed dozens.
According to a report published by news agency Reuters, scientists were working on an early warning system at the glacial lake, which if fully operational could have given people more time to evacuate when the lake overflowed and triggered flash floods in the Teesta river.
Officials said the advanced warning system (AWS) was installed almost a month ago and failed to send out an alert before the lake burst. “Two AWS were installed at Lhonak Lake and Shako Cho Lake between September 9 and September 19 this year. Unfortunately, the system didn’t send any early warning. Most probably it wasn’t working when the incident took place,” VB Pathak, chief secretary of Sikkim, told Hindustan Times.
An expedition to the site last year could not be planned and, so, the project began just weeks before the floods killed at least 37 people with 78 missing. The report in Hindustan Times said two expedition teams, including Swiss scientists, and comprising 14 persons each were sent to the lakes in September to install the AWS. It was a joint operation conceived by the National Disaster Management Authority (NDMA) with Sikkim state disaster management authority and Swiss Agency for Development and Cooperation.
“It was a pilot-project, which was supposed to generate data on the lakes based on which an early warning system (EWS) was to be developed. The data was to be monitored by the Swiss agency. Even though the one installed in Shako Cho was sending data, the one in Lhonak didn’t generate any data,” another senior official told HT.
Krishna S Vatsa, NDMA member, said there was a delay as it was a complex expedition for several reasons including the fact that the lake, high in the mountains on India’s border with China, is accessible only from July to September.
“It was a large inter-agency expedition, which could not be organised last year and had to be done this year because you have to carry a lot of equipment… and there is a limited window to go to the site,” Vatsa told Reuters.
“It’s a sensitive border area so we had to get all clearances,” he said. “…We also had limited time to get there, and we had to get all agencies to agree on one particular date for this expedition.”
Sikkim govt seeks ISRO help
The Sikkim government has sought the help of ISRO now that the Swiss system has failed to generate any kind of alert. “I have written to the chairman of ISRO and director of North Eastern Space Application Centre in Shillong to keep a watch on Lhonak, Shako Cho and other glacial lakes in Sikkim. I have requested them to analyse satellite images and data and let us know if any immediate steps need to be taken. We are receiving regular updates from them,” Mathur was quoted as saying.
A robust response and evacuation model developed by the Sikkim government for such extreme events, however, helped in the evacuation process. Senior officials said residents of Chungthang and other north Sikkim towns and villages, which are vulnerable to flooding events, underwent mock drills at least once a year under special response and evacuation models.
In recent years, glacial flood early warning systems have been deployed in China, Nepal, Pakistan and Bhutan as climate change has raised the risks of flooding. Many communities face dangerous glacial floods as lakes holding water from melted glaciers can overfill and burst their surrounding walls, sending torrents rushing down mountain valleys. More than 200 such lakes now pose a very high hazard to Himalayan communities in India, Pakistan, China, Nepal and Bhutan, as per a 2022 research.
Toll reaches 37 with 78 missing
The toll in the flash flood has increased to 37, while 78 people are still missing six days on, as per state disaster management authorities. Pakyong district accounted for the maximum number of deaths at 24, including 10 army personnel, followed by seven in Gangtok, four in Mangan and two in Namchi districts. Another 78 people are still missing.
A total of 6,001 people have been either rescued or evacuated from flood-affected areas while the number of injured stood at 30. The number of people affected by the flash floods stood at 87,300. A total of 3,773 people were rendered homeless and provided shelter in 24 relief camps.
(With agency inputs)