Steady Loss Of Ice And Mass Recorded In Six Glaciers Of Bhilangana Valley Of Uttarakhand
The study by Dr Rakesh Bhambri and Sharmishtha Halder of Wadia Institute of Himalayan Geology at Dehradun has been published in ‘Regional Environmental Change’ journal
Published : September 2, 2026 at 7:10 PM IST
Dehradun: Authorities in Uttarakhand have gone into alert mode following the Nepal disaster of August 26. A study on records of five decades of six major glaciers in Bhilangana valley in Tehri district has revealed some startling facts. While the rapid melting of Khatling glacier has surprised researchers, a lake forming on another glacier has become a cause for concern for the scientists.
The study of nearly five decades of records has revealed that the six glaciers have experienced a steady loss of ice and mass between 1973 and 2025. The rate of melting and thinning of these glaciers has accelerated significantly over the last decade. The largest Khatling glacier has retreated by approximately 5.33 km, and a rapidly developing lake in front of another glacier has increased the risk of a potential glacial lake outburst flood (GLOF) in future.
The important research has been published in the ‘Regional Environmental Change’ journal on August 28, 2026, under the title ‘Accelerating glacier mass loss in Bhilangana valley since the 1970s’ by Dr Rakesh Bhambri and Sharmishtha Halder of Wadia Institute of Himalayan Geology at Dehradun.
The six glaciers studied include Khatling, Phating, Dudhganga, Ratangarian and an unnamed glacier.
These six glaciers cover approximately 75% of the total glaciated area of the Bhilangana valley. Using satellite data from 1973 to 2025 and digital elevation models (DEMs) from different time periods, the scientists assessed changes in glacier elevation, ice mass loss, area and frontal retreat.
The Bhilangana River is a major tributary of the Bhagirathi and is a vital water source for the Tehri reservoir. Meltwater from glaciers is crucial for hydroelectric power generation, agriculture and the large population in the lower regions. Consequently, the rapid decline of glaciers is feared to impact future water availability.
The study found the most concerning changes in the Khatling glacier, which is melting at a faster rate than the rate the Gangotri glacier had previously recorded. Between 1973 and 2024, the Khatling glacier retreated approximately 5.33 km, which is the largest retreat among the glaciers studied in the Bhilangana valley.
Research says that the impact of the glacier's continuous retreat was so widespread that the Khatling and Phating glaciers, which were previously connected, separated around 2000.
The Phating glacier retreated by approximately 1.825 km between 1973 and 2024. Scientists compared three different periods between 1973-2000, 2000-2014 and 2014-2025 and concluded that the ice mass loss in the Khatling glacier and the unnamed glacier increased four to five times between 2014 and 2025 compared to the period between 1973 to 2000.
While Ratangarian and Jogin glaciers showed slight increases in thickness between 2000 and 2014, both glaciers experienced increased mass loss after 2014. The pressure of ice loss has increased for all six glaciers studied in the recent decade.
Scientists said that the area of all six glaciers decreased between 1973 and 2024. The greatest area loss was with the Khatling glacier, losing approximately 2.79 sq km, Phating losing 0.71 sq km, Dudhganga 0.64 sq km, unnamed glacier 0.50 sq km, Ratangarian about 0.23 sq km and Jogin losing 0.35 sq km.
The study suggests that changes in glaciers are not limited to their tail ends. In recent years, thinning of the ice surface is affecting the upper reaches of glaciers, which are typically considered areas of snow accumulation.
The study has also raised a major concern about an unnamed lake developing in front of the unnamed glacier that had grown to 0.36 sq km by 2024. The scientists have considered this potentially dangerous as rapidly forming or expanding lakes in front of glaciers in the Himalayan regions could lead to future GLOFs.
A GLOF occurs when the natural structure holding back a glacial lake breaks and large amounts of water, debris, and rocks suddenly flow down into the valley below. In mountainous regions, such events can pose a significant threat to roads, bridges, villages and hydroelectric projects.
The scientists believe that rising temperatures and changing rainfall patterns in the central Himalayas are contributing to glacier mass loss. The study has noted that the increasing trend of liquid precipitation replacing solid snow in some areas could increase melting pressure on the lower reaches of glaciers. Glaciers terminating at lower elevations are particularly affected, especially the Ratangriyan and Jogin glaciers which are located at higher elevations.
Large parts of both these glaciers fall within the snow accumulation zone, which led to relative stability for some time, But the increased mass loss in these glaciers during the recent study period is a warning for the future.
The importance of the Bhilangana valley glaciers is not limited to the Himalayan ecology. This region is connected to the Bhagirathi river system and the Tehri reservoir. Water from the glaciers contributes to the local river system, agriculture, and hydroelectric power generation.
The scientists have stated that rapid glacier melt may initially increase the amount of water in rivers, but in the long run, continued shrinking glaciers could deplete natural water reserves, potentially impacting future water availability, especially during dry seasons.
They have concluded that changes occurring across the Bhilangana valley glaciers are not uniform. Each glacier's height, slope, size, direction, and local topographic conditions influence its response. Nevertheless, the increasing mass loss across all six glaciers in recent years is a clear warning. The study's findings indicate that continuous monitoring of glaciers and glacial lakes in the Himalayan regions of Uttarakhand is now crucial, especially for glaciers that are experiencing rapid lake formation.
It has been pointed out that strengthening scientific monitoring, risk mapping and early warning systems will be crucial for future water security and protection against Himalayan disasters.
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