Nepal’s tragedy raises big questions for the Himalaya’s future: Devendra Kumar Sharma calls for fresh review of climate risk, GLOFs and dams

The devastating flash floods that swept through Nepal’s Rasuwa district in late August 2026 have reignited urgent debates over how prepared the Hindu Kush–Himalaya (HKH) region is for a rapidly warming climate. For Devendra Kumar Sharma—president of the International Commission on Large Dams (ICOLD) and a member of India’s National Security Advisory Board—the disaster is not just Nepal’s local catastrophe but a stark warning for the entire mountain arc, from Ladakh and Himachal Pradesh to Uttarakhand, Sikkim and beyond.

Sharma, who was in the region when the tragedy struck, says the event underscores a growing mismatch between old engineering assumptions, outdated flood records and the new reality of accelerating glacier loss, permafrost thaw, and more frequent extreme events. His message is clear: the Himalaya can no longer be managed using 20th-century data and designs.

According to Sharma, the day of the Nepal disaster began with apparently normal weather. For two days prior, conditions had been stable, with no obvious signs of an impending extreme event. Yet within hours, a high-altitude failure—likely involving ice, rock and moraine—triggered a cascade that turned into a deadly flash flood downstream.

Local residents at higher elevations reportedly sensed danger and warned communities below to move to safer ground. But many dismissed the alerts, reasoning that the sky was clear and the weather had been calm. “If those warnings had been taken seriously and people had moved in time, the loss could have been significantly reduced,” Sharma says.

The episode highlights a critical gap in Himalayan disaster management: issuing scientific warnings is not enough. Those warnings must reach last-mile communities in understandable forms, and people must know exactly where to go when alarms sound. Clear skies, Sharma warns, are no guarantee of safety in a landscape where glaciers, permafrost, slopes and river systems can fail suddenly and catastrophically.

GLOFs back in the spotlight

While investigations continue, scientists and officials suspect a Glacial Lake Outburst Flood (GLOF) or a related glacial–moraine failure played a key role in the Rasuwa event. In the HKH, moraine-dammed glacial lakes are common, and numerous past GLOFs have been traced to the collapse of such unstable natural dams.

When a moraine gives way, a lake can drain in minutes, releasing a torrent of water, ice, rock and mud that devastates everything in its path. Hamlets, hydropower plants, bridges, roads and border outposts were all washed away in Nepal’s deluge, with hundreds killed and many more missing.

The disaster has brought GLOFs back into policy focus across the region. As Sharma notes, rising temperatures, retreating glaciers and weakening mountain slopes mean that GLOFs, debris flows, landslides and sudden floods could become more frequent and more severe in the coming years.

A regional risk, not a national one

Sharma stresses that Nepal’s tragedy must not be viewed in isolation. The HKH is a tightly coupled system: glaciers, rivers, rainfall patterns and disaster risks do not respect borders. An event in upper catchments in Tibet or Nepal can rapidly translate into floods, sediment surges and infrastructure damage downstream in India and Bangladesh.

This interdependence makes cross-border cooperation on data, monitoring and early warning not just desirable but essential for human security. “India and Nepal are not just geographical neighbours,” Sharma says. “Their rivers, Himalayan ecology, water resources and disaster risks are interconnected.”

In March 2025, Sharma led a study titled “Proposed Cooperation: India–Nepal Collaboration in the Context of Climate Change,” which was shared with the Nepali government. The report outlined potential climate-driven risks in the HKH—especially GLOFs and other mountain hazards—and ask measures for risk monitoring, data exchange, early warning and adaptation. It specifically flagged August as a month requiring heightened vigilance for glacier-related risks.

The science: HKH glaciers losing ice at double the rate

The broader scientific context is alarming. New ICIMOD reports released in March 2026 show that glacier ice loss across the HKH has doubled since 2000, with the most recent decade recording increasingly frequent extreme melt years.

Two landmark studies—“Changing Dynamics of Glaciers in the Hindu Kush Himalaya Region from 1990 to 2020” and “HKH Glacier Outlook 2026”—document a 12% reduction in glacier area and a steep decline in ice reserves. About 89% of recorded years show negative glacier mass balance, indicating consistent retreat.

This is not just an environmental statistic. Accelerating glacier loss intensifies GLOF risks, disrupts water availability for high-mountain communities, and threatens the long-term flow regimes of the Indus, Ganga and Brahmaputra—river systems that support nearly two billion people.

ICIMOD has also mapped more than 25,000 glacial lakes across five major HKH river basins in a 2018 report, “The Status of Glacial Lakes in the Hindu Kush Himalaya.” That study remains a foundational reference for identifying potentially dangerous lakes and planning risk-reduction measures.

Sharma’s warnings carry particular weight for India’s western Himalaya. A recent scientific study, “Sensitivity of the Himalayan Region Under Climate Change,” analysed 120 years (1901–2020) of temperature records and eight global climate models. It found that the western Himalaya—covering Ladakh, Jammu & Kashmir and Himachal Pradesh—is warming faster than the central and eastern Himalaya, with rising temperatures in every season.

Under high-emission scenarios, winter temperatures in the western Himalaya could rise by more than 7°C by the end of the century compared to the early 20th century. The study also warns of severe future snow loss, with profound implications for snowpack, glaciers, spring-fed streams and river flows.

For states like Himachal Pradesh, which has already seen deadly cloudbursts and flash floods in recent years, these findings are a direct policy signal. The same dynamics that contributed to disasters in Uttarakhand’s Chamoli in 2021 and now in Nepal’s Rasuwa are increasingly relevant for the western Himalaya.

From relief-centric to risk-centric disaster management

Sharma argues that Himalayan disaster policy can no longer be primarily relief- and rehabilitation-centric. “We must move from reacting after disasters to acting before they happen,” he says. That means systematic risk assessment, continuous monitoring of glaciers and glacial lakes, and robust early warning systems that connect science to communities.

He advocates a layered approach: Satellite remote sensing and space-based monitoring to track glacier changes, new lake formation and slope instability. Ground-based instruments and local observation networks to validate satellite data and detect rapid changes. Last-mile communication systems—mobile alerts, community radios, local sirens—to ensure warnings reach villages in time.

But technology alone is not enough. Sharma emphasises that every settlement in hazard-prone zones must have pre-identified safe sites and evacuation routes. “Telling people to ‘evacuate’ is meaningless if they don’t know where to go,” he says. Community drills, local risk maps in local languages, and integration of indigenous knowledge with scientific data are all part of the solution.

Rivers, construction and the limits of “scenic” development

Another critical issue Sharma raises is unchecked construction along Himalayan rivers. In many mountain states, hotels, homes and infrastructure have crept into natural floodplains and river corridors, often in the name of tourism and “scenic” development.

Himalayan rivers flow down steep gradients and can change course rapidly during extreme rainfall, landslides or glacial events. Building in their natural pathways without proper hazard mapping multiplies future losses. Sharma calls for strict regulations on construction near riverbanks, flood-prone zones and natural river corridors, coupled with enforced no-build buffers.

For policymakers, this means reconciling development aspirations with ecological limits. The question is not whether to develop, but how to develop safely in a high-risk, climate-stressed mountain environment.

Hydropower, dams and the need for a design overhaul

In the aftermath of Himalayan disasters, hydropower projects are often singled out as culprits. Sharma cautions against simplistic blame. “It is not scientifically correct to hold hydropower projects solely responsible for every Himalayan disaster,” he says. Climate change, rising temperatures and evolving geo-hydrological conditions are central drivers.

That said, he insists that the design and safety standards of dams and hydropower infrastructure must be urgently revisited. Many large dams in the region were designed using historical flood and sediment data from a cooler, more stable climate. “Just because a certain flood magnitude was the maximum in the last 100 years does not mean a larger flood cannot occur in the future,” Sharma notes.

ICOLD, under his leadership, is actively discussing how new dams should be designed for future climate scenarios and how existing dams can be retrofitted with additional safety measures. This includes reassessing spillway capacities, sediment management, extreme flood routing and seismic resilience in light of new climate projections.

After the Nepal tragedy, Sharma held detailed discussions with Nepali hydropower engineers, laboratory experts and academics on adapting designs to changing risks. The consensus: future projects cannot rely on past climate normals. Designs must account for more intense rainfall, higher sediment loads, debris flows and compound hazards.

Sharma also underscores the equity dimension of climate risk. The Himalaya is paying the price for historical emissions largely generated by industrialised nations. Yet it is mountain communities in countries like Nepal and India who face the brunt of glacier loss, GLOFs and water insecurity.

He argues that countries with better technology, scientific capacity and financial resources must support vulnerable Himalayan states. This includes access to modern monitoring systems, satellite data, early warning platforms and risk-assessment tools. “Developed nations must help,” he says. “This is not charity; it is climate justice.”

In this context, India–Nepal cooperation takes on strategic importance. Shared glacier and glacial-lake databases, joint satellite monitoring, co-developed risk maps and harmonised early warning protocols can save lives on both sides of the border. For India, investing in Nepal’s resilience is also an investment in its own downstream security.

The Rasuwa disaster is more than a story of ice, rock and water. It is a story of how a warming climate is rewriting the rules of mountain safety, and how institutions, infrastructure and communities must adapt or suffer repeated losses.

Sharma’s message is uncompromising: the Himalaya is entering a new risk regime where old experience and old design codes are no longer sufficient. Western Himalaya’s accelerated warming, expanding glacial-lake hazards and weakening slopes demand a new generation of policies grounded in science, technology, local knowledge and regional cooperation.

As Sharma puts it, “The strategy for the Himalaya in this era of climate change must be based on science, technology, local experience, international cooperation and new-generation safe infrastructure standards.” Anything less will leave millions exposed to avoidable disasters.