Itanagar, Nov 15: In a landmark scientific breakthrough, a joint team from the Goa-based National Centre for Polar and Ocean Research (NCPOR) and the Centre for Earth Sciences and Himalayan Studies (CESHS), Itanagar successfully achieved the first-ever scientific access to Dharkha Tso, one of the high-risk glacial lakes identified by the National Disaster Management Authority in the upper Khangri region, Arunachal Pradesh.
The achievement marks a major milestone in India’s ongoing efforts to strengthen high-altitude cryospheric research and enhance preparedness against potential glacial hazards, officials said on Saturday.
The mission formed a critical part of the 4th Khangri Glacier Scientific Expedition, undertaken by an interdisciplinary team of glaciologists, geologists, climate scientists, and high-altitude field experts, from November 8 to 14.
The expedition aims to strengthen scientific research on glacier health, climate change impacts, and hydrological behaviour in the Eastern Himalaya. Since its inception in 2023, the Khangri Glacier Expedition series has focused on long-term monitoring of glacier systems to build robust datasets for cryospheric and water-resource studies.
This year’s scientific team consisted of 11 experts, including glaciologists, engineers, and researchers from CESHS, NCPOR, Nagaland University, and NERIST, Nirjuli. The mission was led by eminent glaciologist Dr Parmanand Sharma, Scientist G, with field operations coordinated by Er Nyelam Sunil, Technical Officer and Head of the Cryosphere Division, CESHS.
CESHS Director Tana Tage said that despite challenging terrain and adverse weather, the team undertook several high-impact scientific tasks. High-resolution drone surveys were conducted over the Khangri Glacier and Rani Lakes using advanced platforms with precision sensors.
He informed, heavy snowfall prevented access to the glacier for direct mass balance measurements, but aerial imagery ensured the completion of glacier and lake mapping.
An unmanned sonar-based bathymetric survey of Rani Lake revealed aquatic life at a depth of 20 metres, a rare discovery for a high-altitude glacial lake.
Researchers successfully retrieved crucial summer-season data from the Automatic Weather Station (AWS) and Automatic Water Level Recorder (AWRL) installed earlier.
24-hour stream discharge measurements were conducted downstream of the Khangri Glacier to analyse meltwater variability and hydrological responses.
The landmark achievement of this year’s expedition was the first scientific scaling and reconnaissance of Dharkha Tso, classified under NDMA Category B GLOF-risk lakes.
Dharkha Tso (meaning “as white as curd” in the local language) is one of the 29 glacial lakes identified as Glacial Lake Outburst Flood (GLOF)-susceptible in Arunachal Pradesh.
Located in the remote Mirathang Valley of Mago Circle at an altitude of 16,145 ft (4,921 m), the lake has no established access route. Starting from the Mago Chu River, the team trekked 3.8 km with a steep climb of 1,710 ft, completing the ascent in 4 hours 40 minutes.
The approach was marked by extreme challenges including over 3 feet of fresh snowfall, treacherous gorges, steep ridges, unstable pathways, and low oxygen levels.
Despite these harsh conditions, the team reached the lake and carried out aerial drone surveys, water sampling, and sediment sampling. These datasets will feed into detailed studies on GLOF risk assessment, early-warning indicators, and mitigation planning, Tage said.
The successful completion of the 4th expedition marks another significant step in India’s efforts to better understand glacier dynamics, meltwater contributions, hydrometeorological shifts, and potential GLOF hazards in the Eastern Himalayan region.