What a hanging glacier collapse could do to Badrinath: New study spells out risks

The study identifies a serious avalanche risk for Badrinath if one of three hanging glaciers detaches. A collapse could send ice, water and debris down the mountain toward the town. This matters because Badrinath is a major pilgrimage centre beside the Alaknanda River, with many buildings and visitors concentrated in a limited area.

The largest simulated threat came from the second glacier site. It contains an estimated 5.32 million cubic metres of ice and has a mean slope of 34.57 degrees. Simulations gave the resulting avalanche a peak velocity of 78.5 metres per second and a flow height of 73.5 metres.

The Badrinath Dham shrine was not expected to be directly hit, but accumulated rock and debris could affect it. Researchers said all three glaciers require attention, and called for hazard mapping, buffer zones, mitigation planning and limits on new construction.

A hanging glacier is an ice body located on a mountain slope or ending abruptly at a bedrock cliff. It is detached from the valley floor rather than resting continuously along it. That position can make the glacier vulnerable to detachment or slope failure, especially when the ice mass is unstable.

If part or all of the glacier breaks away, gravity drives the ice rapidly down the mountain. The moving ice can release a large volume of water and debris over a short duration. The resulting avalanche may therefore reach areas below the glacier with substantial force and height.

The study examined three hanging glaciers between 4,700 and 5,465 metres above sea level. Researchers used satellite imagery, elevation models and avalanche simulations to assess their volume, depth, vulnerable portions and possible effects on Badrinath.

The second hanging glacier site produced the largest simulated risk among the three sites studied. Researchers estimated its volume at 5.32 million cubic metres. Its mean surface slope was 34.57 degrees, making it one of the steep, potentially unstable glaciers selected for detailed modelling.

In the simulated failure, the avalanche reached a peak velocity of 78.5 metres per second. Its flow height reached 73.5 metres. These figures describe the modelled movement of the released material, including its speed and vertical reach as it travelled downslope.

The results represent a worst-case scenario, not a prediction that a collapse will occur. The researchers noted uncertainty in friction parameters and flow behaviour. Ice thickness and release volumes also came from remote sensing and model estimates rather than direct field measurements, which may affect the absolute values.

The study’s worst-case scenario covers several important parts of Badrinath. It estimates possible damage to nearly 398 buildings and 2.66 kilometres of roads. The affected infrastructure could also include two bridges, a helipad and a parking area.

The threat comes from an ice avalanche and the material it carries downslope. A collapsing glacier can release ice, water and debris in a short period. Rock and debris may accumulate during the event or be pushed into the town, increasing damage beyond the initial movement of ice.

The Badrinath Dham shrine was not expected to be directly hit in the simulations. However, the study warned that rock and debris typically accumulated during such events could still impact it. Researchers therefore recommended impact zones, buffer zones and restrictions on new infrastructure based on worst-case runout estimates.

Warming conditions can change how a glacier is supported against the ground. The study says that as glaciers transition toward more temperate conditions, reduced basal resistance increases the likelihood of ice detachment and large-scale failure. In simple terms, less resistance at the base can make the ice mass easier to release.

Steep slopes increase the danger because gravity pulls unstable ice downhill more strongly. In this study, glaciers with mean surface slopes of at least 30 degrees were screened for instability. The most dangerous simulated site had a mean slope of 34.57 degrees, along with an estimated volume of 5.32 million cubic metres.

Slope alone does not prove that a collapse will happen. Researchers also considered each glacier’s location, volume, depth and vulnerable portions. They stressed that the modelling contains uncertainty, especially in friction values, release volumes and ice-thickness estimates.

Hazard mapping can translate glacier modelling into clear zones of possible danger below a mountain. Maps based on worst-case runout can show where ice, water, debris and flow might reach. This gives authorities a basis for planning roads, buildings and emergency measures before an event occurs.

Buffer zones add physical separation between unstable glaciers and vulnerable infrastructure. Restrictions on new construction can stop towns from expanding into areas identified as avalanche impact zones. Together, these measures reduce the number of buildings, bridges and facilities exposed to a sudden flow.

The researchers called for demarcating avalanche impact and buffer zones using the highest possible runout of glacial material, debris and flow. They also recommended restricted regulations on new construction and infrastructure. The approach could support hazard assessment for other towns near hanging glaciers, but the study noted modelling uncertainties.

An ice avalanche begins when an unstable hanging glacier detaches from a mountain slope or cliff. Gravity then drives the released ice downslope. Because the glacier is elevated above the valley floor, the moving mass can gain speed and travel toward lower ground.

As it moves, the avalanche can release a large volume of water and collect or push rock and other debris. The combined flow becomes heavier and more destructive than ice alone. Its height, speed and runout determine which buildings, roads and other structures may be reached.

At Badrinath, the study modelled these processes for three hanging glaciers. The second site produced a simulated peak velocity of 78.5 metres per second and a flow height of 73.5 metres. The researchers used these estimates to assess possible damage and identify areas needing hazard mapping and mitigation planning.