It started excessive above the villages of Nepal, in part of the Himalayas the place few folks might have seen the catastrophe coming.
On August 26, an enormous wall of ice, rock and particles broke unfastened close to the Nepal-Tibet border and got here crashing down the mountainside. Inside moments, the distant Himalayan panorama was reworked right into a lethal chain response.
The avalanche slammed into the Bhote Koshi river system, choking and redirecting the circulate earlier than unleashing a violent surge downstream. The flood raced by means of mountain valleys with terrifying velocity.
Bridges disappeared. Roads have been lower off. Buildings have been swallowed by mud, boulders and particles. In Betrawati, satellite tv for pc imagery later revealed components of the industrial coronary heart of the city buried beneath the wreckage, whereas energy infrastructure and important hyperlinks to the skin world have been broken.
However maybe probably the most unsettling discovery got here after the flood.
Satellite tv for pc photos of the catastrophe zone revealed that the avalanche had left behind a newly shaped lake on the supply of the disaster. Excessive within the mountains, water was starting to build up behind the particles, elevating fears of one other potential outburst in an already devastated river system.
For India, the pictures from Nepal carry an uncomfortable message. The Himalayas don’t recognise political borders.
The glaciers, unstable slopes and quickly altering high-altitude lakes that triggered concern in Nepal proceed throughout the Indian Himalayas.
From Himachal Pradesh to Sikkim and Arunachal Pradesh, glaciers are retreating, new lakes are forming and present lakes are increasing.
Might the subsequent Himalayan catastrophe unfold on the Indian facet?
INDIA ON ALERT: HIMALAYAS BECOMING UNSTABLE
Scientists warning that it could be unsuitable to foretell that India will expertise a precise repeat of Nepal. Each mountain, glacier and river valley has its personal geology and triggers.
However analysis from the Indian Himalayas is revealing warning indicators which might be turning into more and more troublesome to disregard.
The query is not merely whether or not a glacial lake can burst.
The larger concern is what occurs when an already fragile Himalayan panorama begins to fail in sequence, when a glacier collapses, an avalanche crashes right into a lake, a landslide blocks a river, excessive rain destabilises a slope, and thousands and thousands of tonnes of water and particles immediately discover a path downhill.
And within the slim, closely populated valleys of the Himalayas, there could also be little or no time to get out of the way in which.
The tragedy has now despatched an uncomfortable query echoing throughout the Indian Himalayas: Might a Nepal-like flash flood disaster strike India?
COULD A NEPAL-LIKE FLASH FLOOD CATASTROPHE STRIKE INDIA?
The reply from scientists shouldn’t be a easy sure.
India can not scientifically predict that Nepal’s tragedy will repeat itself throughout the border. The exact triggers, geology, glaciers and river valleys are completely different. However the warning indicators are more and more seen.
Throughout the Himalayas, glaciers are retreating, lakes are rising, slopes have gotten unstable, and infrastructure is increasing deeper into slim mountain valleys. The components for catastrophe exist.
The uncertainty lies not in whether or not the mountains are altering, however in understanding precisely when and the place the subsequent cascade might start.
Professor Dericks Reward Shukla, Professor of Distant Sensing and GIS at IIT Mandi, says the primary activity is to grasp the place the hazard is concentrated.
His workforce’s evaluation of Himachal Pradesh recognized roughly 2,000 lakes and in contrast their extent between 2015 and 2025. The analysis then categorised them in keeping with whether or not they have been instantly linked to glaciers, disconnected from them or positioned shut sufficient to doubtlessly obtain glacier-fed water.
Lakes constantly fed by melting glaciers are notably vital as a result of they proceed to obtain recent water enter.
However a rising lake doesn’t routinely imply an impending catastrophe.
That is likely one of the most vital distinctions rising from the analysis.
The IIT Mandi evaluation examined not simply lake dimension but additionally the fabric forming the pure barrier holding the water again. A lake contained by solid bedrock presents a really completely different hazard from one held behind unfastened particles. Moraine dams could also be stronger than unconsolidated particles, however they continue to be weaker than bedrock.
The researchers additionally examined the scale of those pure limitations, together with their size, width and peak. The bodily traits of the dam can affect how weak it might be to failure.
Over the previous decade, the quantity and complete space of glacier lakes in Himachal Pradesh have elevated, in keeping with the evaluation. The researchers then used a number of parameters and skilled inputs to price the lakes, with round 9 rising as extremely crucial and doubtlessly harmful.
But hazard shouldn’t be the identical factor as threat.
COULD THESE GLACIAL LAKES BREACH?
A lake might have the potential to breach and launch a big quantity of water, but when there are not any villages, roads, hydropower projects or other assets downstream, the results could also be restricted.
Conversely, a smaller occasion in a densely populated valley full of infrastructure can flip into a serious catastrophe.
“Catastrophe threat exists solely when uncovered parts are current within the path of a hazard,” the evaluation shared by Suhora Applied sciences famous. These uncovered parts embrace settlements, roads, bridges, tunnels, dams, faculties and healthcare amenities.
A rising lake, due to this fact, turns into a way more severe concern when weak communities and infrastructure lie downstream.
This distinction is essential when lakes corresponding to Samudra Tapu in Himachal Pradesh.
The lake is linked to the Tapu Glacier, is giant and has been increasing. It might doubtlessly generate a big flood if it breached. Nonetheless, the evaluation means that its overall downstream risk is relatively lower as a result of settlements and different property are distant and the river slope downstream is relatively mild.
That doesn’t imply India can chill out.
INDIA NEEDS TO ENHANCE MONITORING
The Himalayas are notably harmful as a result of disasters hardly ever happen in isolation.
A glacier or ice-rock avalanche can fall right into a lake. A landslide can block a river and immediately create a short lived lake.
Excessive rainfall can destabilise slopes. An earthquake can weaken a pure dam. A quickly increasing glacial lake can breach.
One occasion can set off one other.
The Nepal tragedy itself illustrates this cascading hazard. In line with the evaluation shared by Suhora Applied sciences, the catastrophe was triggered by an ice-rock avalanche quite than a traditional Glacial Lake Outburst Flood, or GLOF. However the particles altered the river system and created a brand new lake on the supply of the catastrophe.
Satellite tv for pc imagery captured on August 27 recognized the newly shaped water physique within the Lhende Khola area, masking roughly 20.25 hectares. A lake shaped on the supply of an avalanche and debris-flow occasion might proceed accumulating water, making its stability a crucial challenge for monitoring.
Union Dwelling Secretary Govind Mohan reviewed the preparedness of Himalayan states and Union Territories towards the dangers of Glacial Lake Outburst Floods (GLOFs) and snow avalanches on Thursday.
Vulnerabilities and preparedness measures particular to every state and UTs have been mentioned intimately, with emphasis on guaranteeing that mitigation measures are translated into concrete actions on the district and native ranges.
INDIA NOT UNTOUCHED BY GLACIAL DISASTERS
India has already witnessed how devastating Himalayan cascades might be.
The 2021 Chamoli catastrophe, the South Lhonak Lake outburst in Sikkim in 2023, the Dharali deluge and main landslide disasters have repeatedly demonstrated that mountain hazards can quickly rework into downstream catastrophes.
Scientists might be able to determine weak areas, however predicting the precise second when a slope collapses, or a pure dam fails stays terribly troublesome.
For Himachal Pradesh, Professor Shukla says the subsequent main scientific step is hydrodynamic modelling.
Figuring out a doubtlessly harmful lake is simply the start. Scientists then have to know the way a lot water it incorporates and what would occur if it breached. Hydrodynamic fashions can estimate flood depth, lateral unfold and the way the flood wave would journey by means of a river valley.
However correct modelling requires dependable details about lake quantity.
Distant sensing can exactly observe modifications in lake space, however estimating water quantity from satellite-derived space alone can contain important uncertainty. Empirical formulation might overestimate volumes considerably, making it troublesome to precisely mannequin the results of a possible breach.
Some Himalayan lakes have already been studied in larger element. Analysis on Gepang Gath in Himachal Pradesh has prompt {that a} main outburst might have an effect on downstream areas, together with settlements round Sissu, with impacts extending additional alongside the valley.
Nonetheless, Professor Shukla cautions towards making dramatic predictions.
It will not be scientifically right to declare {that a} Nepal-like catastrophe will occur in Himachal Pradesh. The bodily mechanisms that set off Himalayan disasters range from place to put.
What scientists can say is that hazardous lakes exist, glaciers and landscapes are altering, and an occasion at some areas might harm communities and infrastructure downstream.
The warning indicators aren’t restricted to Himachal Pradesh.
WARNING SIGNALS ACROSS HIMALAYAS
An evaluation by Suhora Applied sciences in Arunachal Pradesh’s Tawang district discovered that 4 of 5 doubtlessly harmful glacial lakes within the Mago Chu Basin had expanded between 2016 and 2026.
The lakes had beforehand been recognized in high-risk classes, and satellite tv for pc observations confirmed altering patterns of water accumulation.
Sanhapo Lake stood out within the evaluation. Satellite tv for pc observations confirmed its measured space growing from 55.87 hectares in 2016 to 87.02 hectares in 2026 and 88.81 hectares within the newest June 2026 commentary.
Suhora’s evaluation mentioned its dimension, continued enlargement and present high-risk classification made it a precedence for detailed hazard modelling and steady monitoring.
For Professor Shukla, the way in which ahead is to not try the not possible activity of predicting the precise date of the subsequent Himalayan disaster.
It’s to construct a greater system for seeing hazard earlier than it arrives.
Meaning satellites scanning huge mountain areas for altering lakes and unstable landscapes, adopted by focused deployment of floor sensors on the most crucial areas. His analysis factors to a two-tier method: broad synoptic monitoring from area to determine hotspots, adopted by centered on-ground monitoring and warning techniques.
The Himalayas might by no means provide excellent predictions.
However Nepal’s tragedy has delivered a robust shakeup: disasters within the mountains can start with a collapse that no person sees, excessive above a valley the place folks beneath might do not know what’s coming.
India might not face an an identical catastrophe. It doesn’t have to.
The Indian Himalayas have their very own glaciers, lakes, valleys and vulnerabilities. And more and more, they’re sending indicators that the time to review the subsequent disaster is before the mountain begins to move.
– Ends
