Arunachal's Tawang on alert over possible glacial lake flood threat

Authorities in Arunachal Pradesh's Tawang district have stepped up preparedness measures amid concerns over a possible Glacial Lake Outburst Flood (GLOF) in the Mago Chu basin, following warnings from scientific experts about climate-related risks in the region.

The Tawang district disaster management department issued an alert after receiving inputs from the Centre for Earth Science and Himalayan Studies (CESHS), which flagged the possibility of a GLOF linked to rapid glacier retreat and unstable terrain around the Khangri Glacier.

The advisory has been shared with the Indian Army, Indo-Tibetan Border Police (ITBP) and Border Roads Organisation (BRO) to ensure coordinated preparedness among all agencies.

Tawang Deputy Commissioner and District Disaster Management Authority (DDMA) Chairman Namgyal Angmo urged residents to remain vigilant and follow official advisories. Superintendent of Police Tasi Darang also advised people living along the Mago Chu and Tawang Chu river systems, particularly in low-lying areas, to keep emergency supplies ready and stay prepared for any eventuality.

To assess the situation on the ground, Thingbu Assistant Commissioner Thutan Wangchu, accompanied by residents of Mago village, recently conducted an inspection of the Khangri Glacier, locally known as Neh-Goh Gangri.

The assessment found that the glacier, located at an altitude of over 17,000 feet on the western edge of the Gorichen range, has experienced noticeable snow and ice loss over the years. Villagers told officials that the mountain range, once heavily covered in snow, has undergone significant melting due to rising temperatures and changing climatic conditions.

Officials also inspected Neh-Goh Tso, a glacial lake situated at around 15,000 feet below the glacier and identified as a potential source of a GLOF.

According to the assessment, the lake's water level remains well below the moraine dam and water is flowing normally through its outlet into the Mago Chu river. Officials observed that the outflow appeared greater than the inflow from glacial melt, indicating limited water accumulation and reducing the likelihood of an immediate outburst.

The lake's outlet was also found to rest on a stable rocky bed, making erosion under current conditions unlikely. Additionally, broad valleys above Merathang, Jethang and Mago could help absorb and dissipate the force of any sudden water surge before it reaches downstream settlements.

However, officials cautioned that geological changes around the lake could quickly alter the risk scenario. The assessment report has recommended a detailed scientific study of glacier retreat, lake depth, water volume, inflow and outflow patterns, and the stability of the moraine dam to strengthen future hazard assessments.

Glacial Lake Outburst Floods are among the most serious climate-related threats in the Himalayan region. They occur when natural barriers containing glacial lakes fail, releasing large volumes of water downstream within a short period and potentially causing widespread destruction.

Meanwhile, continuous rainfall has triggered severe waterlogging near the Inter-State Bus Terminus (ISBT) complex at Lekhi, disrupting traffic and causing inconvenience to commuters. Residents blamed inadequate drainage infrastructure for the recurring flooding and called for urgent intervention by the authorities.