What Actually Caused the Nepal Disaster

Everyone wants to talk about climate change, the actionable causes lie elsewhere

Aug 29, 2026

The many videos I’ve seen from the Nepal glacier/rock flood are horrific and tragic. They remind me of those of the 2004 Boxing Day tsunami. The death toll is sure to run into the thousands, likely making the event’s mortality one of the top non-earthquake events this century.

As now happens in the aftermath of every disaster, the metaphorical ambulance chasers of climate advocacy seem to dominate the discussion of why it happened and what to do in response — NPR, the New York Times, the Associated Press and many others have each spent days trying to convince us that climate change caused the disaster (or made it more likely), and that emissions reductions are the solution.

The stampede of climate reductionism once again has us missing what matters most for saving lives in the future.

Today, I argue that we know exactly why the disaster happened and what we need to do to reduce the risks of future such disasters.

A precipitating event — a hurricane, an earthquake, or a glacial/rock collapse — is necessary for a disaster to result, but that event is never sufficient. Human exposure and vulnerability are also necessary elements, and almost always the ones that we can most effectively influence in the very near term.

In the case of the Nepal disaster, the number of people in the region exposed to flood risk has increased dramatically over recent decades. The figure below shows that the population of the affected districts increased by nearly a million people over four decades.

Nepal Electricity Authority reports 14 hydropower projects damaged — nine operating plants plus five under construction. Those plants had workers and those constructing the new plants right in the path of the flood. As of this writing, more than 900 hydropower workers are missing. The damaged operational plants accounted for about 8% of Nepal’s total generating capacity.

Tourism has recently increased as well, doubling in August from 2022 to 2025, as part of the post-pandemic rebound, as shown below. That meant many more people sitting in buses at the border crossing in the image at the top of this post at the moment the flood struck.

The people in the region represent exposure to risk. Given that exposure, we can ask: What actions would have saved lives in the event by reducing their vulnerability to harm?

The answer starts with knowing where risks exist and providing a way to warn people downstream of an impending event before the water arrives. That means cataloging potential hazards and putting into place early warning systems.

Until January 2025 the United States supported this type of vulnerability reduction in Nepal and across the broader region. Specifically, SERVIR-Hindu Kush Himalaya (HKH) was a joint USAID and NASA program with ICIMOD in Kathmandu, serving as a regional hub, covering Afghanistan, Bangladesh, Myanmar, Nepal and Pakistan.

The program applied satellite Earth observation and geospatial analysis to disaster risk reduction, water resources, land cover and air quality. Its concrete outputs include Nepal’s National Land Cover Monitoring System, annual forest-fire monitoring, flood and drought risk services, collaboration with the Nepal Red Cross Society on risk communication, and a collection of more than 170 public datasets covering glaciers, land cover, disasters and vulnerability. The program described the region as acutely exposed to water-induced disasters given its fragile geology, rugged terrain and monsoon regime, and characterized inefficient risk communication as increasing risks of disasters.

The SERVIR-HKH informs users that the initiative formally concluded in January 2025. ICIMOD’s 2025 year-end review lists it among three projects hit by the withdrawal, termination or restructuring of U.S. funding. SERVIR’s history page explains that the twenty-year USAID–NASA partnership ending in 2025. Across Nepal, the Kathmandu Post documented $321 million in terminated U.S. assistance when the Trump administration announced cuts of 83%, before shuttering the agency.

Jeremy Konyndyk, who ran the USAID response to the 2015 Nepal earthquake, wrote this week on X that DOGE keyword searches across programs included “climate” and that identified the USAID–NASA collaboration on flood prediction, early warning, disaster readiness, glacier inventories and the mapping of dangerous glacial lakes in Nepal, along with seven other Nepali disaster-risk-reduction projects.

These “climate” programs were then targeted for termination.

Konyndyk asks:

“Could these programs have helped foresee or mitigate this week's glacial flooding catastrophe? Hard to say with an outlier event like this. But that was their purpose.”

Nature India explains that, “The Hindu-Kush Himalaya holds the largest volume of ice outside the polar regions and feeds ten major Asian river systems.” The characteristics of sudden-onset flood events mean that:

“Downstream settlements could have as little as five to thirty minutes of warning before a flood wave arrives, too short for evacuation without automated detection and alert systems. More than 200 glacial lakes across the Himalaya are classified as ‘very high risk’ for downstream communities, but new evidence shows that smaller lakes can also pose a serious threat.”

From the many videos of the event, it is seems clear that most (if not all) people in the path of the flood had no warning at all, and many lives could have been saved with even minutes of warning.

However, effective warning systems are not widely in use in the region:

“Early warning systems using remote sensors, cameras and satellite monitoring have been piloted in Nepal, Bhutan, Pakistan and parts of China. However, coverage remains sparse, and expeditions to install or maintain sensors above 5,000 metre are logistically difficult, costly, and limited to short summer windows. Nepal’s hazard sits in a transboundary basin. The glaciers and upstream monitoring infrastructure lie partly in Chinese territory. So effective warning depends on data-sharing and coordination across the border.“

The lack of an effective warning system is being discussed in the region. One regional news organization has an excellent report, worth quoting in some detail:

The devastating flood that tore through Nepal’s Bhotekoshi river corridor on August 26 has raised questions about whether the country’s flood early warning system is equipped to deal with sudden and extreme events.
According to the Department of Hydrology and Meteorology, the flood travelled about 36 kilometres from the Nepal-China border to Betrabati in roughly 40 minutes, an unusually rapid movement compared with previous floods.
Binod Parajuli, chief of the department’s Flood Forecasting Section, said a sensor near the Nepal-China border was transmitting flood data every 10 minutes. Data were received normally until 8:40am, but the 8:50am reading was not received.
Another sensor at Betrawati, about 36km downstream, continued transmitting data until 9:20am. Its 9:30am reading was also not received.
The timing suggests that the flood entered Nepal between 8:45am and 8:50am and reached Betrabati at around 9:25am.
“This means the flood was moving extremely fast compared with other floods in the past,” Parajuli said.
Previous floods have taken about 14 hours to travel from the Nepal-China border to Devghat, he said. The August 26 flood reached Devghat in about seven hours, with a recorded discharge of around 200 million cubic metres of water.
The extreme flow also destroyed flood monitoring equipment at Langtang, Rasuwagadhi, Betrabati, Syafrubesi and Malekhu. Only the stations at Devghat, Bhorle and Kalikhola near Muglin remain operational.
“We had installed most of the equipment on bridges, considering them relatively safe and strong structures,” Parajuli said. “But the bridges themselves were swept away, along with the equipment.”

One flood warning expert, Anup Khanal, explained:

“authorities need to examine the entire system — including sensor capacity, data transmission, warning thresholds, sensor elevation, backup systems, the flow of warning information and whether equipment can continue operating during extreme disasters.
A technical investigation should determine how long each sensor transmitted data, when communication failed, when the stations were damaged, what the actual nature of the flood was and whether the available data provided enough time to issue warnings.
“The incident shows that Nepal’s flood early warning system needs to evolve beyond simply measuring water levels,” Khanal said. “It must be capable of surviving extreme floods, transmitting data rapidly, using backup sensors and issuing immediate warnings based on risk levels.”
He also stressed the need for continuous satellite monitoring of glacial lakes considered at risk of bursting.”

The technologies exist that are necessary for implementation of an effective early warning system in the Himalayan region — including both detection and alerts:

A 2019 survey in Frontiers in Earth Science catalogued the remote-sensing tools available for cascading hazards across High Mountain Asia — defined there as a primary trigger like heavy rainfall, seismic activity or snowmelt.
In 2022, an integrative screening method in Science of the Total Environment identified potentially dangerous glacial lakes across the Himalaya.
And in December 2025 the Bulletin of the American Meteorological Society published a design for a Himalayan GLOF (glacial lake outburst floods) monitoring network.

What is lacking is not the knowledge or technology, but the funding and expertise necessary for deployment and implementation of a system that works across the region in the context of conventional flash floods, GLOFs, glacial/rock landslides, or other hazards.

That’s where the U.S. funding cuts matter — whether or not the funding came through any one agency or another, the United States is one of the few nations around the world with the resources to help less wealthy countries implement such systems in support of vulnerability reduction. Such efforts would not just save lives, but strengthen alliances in support of U.S. interests.

Some might say it is not the responsibility of the United States to support disaster risk reduction in places on the other side of the planet.

To them I’d simply respond: First, if the U.S. can contribute to the saving of thousands of lives anywhere — by investing dollars, expertise, technologies, or other resources, ideally in collaboration with other nations — that is money well spent. It is also the right thing to do.

And second, more parochially, some 90 Americans are missing in the Nepal floods. It turns out that the world is a pretty small place and we are all connected.

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