For this disaster, I have conducted an interview with Xu Shiling. She is the Deputy Director of the International Humanitarian Law and Humanitarian Policy program at the International Academy of the Red Cross, Soochow University. Below is the summary I made from the interview. I’m using AI to help me edit this newsletter.
The Nepal August 26 Mudslide, which began with a glacier collapse high in Nepal’s mountains and swept through areas along the China–Nepal border, was not caused by a single isolated factor. It resulted from a combination of extreme Himalayan terrain, an increasingly unstable mountain environment and the exposure of communities and infrastructure along the flow’s path.
That is the assessment of Xu Shiling, Deputy Director of the International Humanitarian Law and Humanitarian Policy Program at the International Academy of the Red Cross, Soochow University, who said the conditions behind the disaster had been developing for years—even though the destructive flow unfolded in only a matter of minutes.
The debris flow traveled approximately 22 kilometers, descended nearly 4,000 meters and reached the affected border area in just six to seven minutes. These figures demonstrate the extraordinary speed and intensity of the event, Xu said.
A disaster years in the making
The geography of the Himalayan region was one of the fundamental factors behind the disaster.
Deep, narrow river valleys cut through enormous glacier-covered mountains. Over geological time, this landscape created the conditions in which ice and rock could accumulate immense potential energy. Once part of the glacier collapsed, the steep drop and confined valley allowed the material to accelerate rapidly and move downhill with enormous destructive force.
“The six to seven minutes were, in fact, a long time in the making,” Xu said, explaining that the drivers of the disaster had existed well before the glacier collapse itself.
In recent decades, the surfaces of the region’s mountains have become increasingly unstable. Xu identified climate change and global warming as important contributing factors. Rising temperatures can weaken glaciers while also destabilizing the rock, soil and loose material beneath and around them, increasing the possibility of fractures, slope failures and collapses.
Xu also pointed to the potential long-term effects of the powerful earthquake that struck Nepal in 2015. The earthquake affected glaciers, rock formations and soils across the region, leaving some mountain slopes more fractured and prone to failure.
In the August 26 event, part of a glacier tongue collapsed together with rock and other material. As the mass rushed downhill, it picked up additional loose debris and developed into an extremely fast-moving flow.
Similar events have occurred elsewhere in the Himalayas, Xu noted. What made this disaster especially destructive was not only the magnitude of the hazard but also the concentration of people and infrastructure along its route.
A major border port, surrounding communities and areas of intensive human activity lay in the path of the flow. The event therefore illustrates a central principle of disaster-risk analysis: a natural hazard becomes a human disaster when it intersects with exposed and vulnerable populations.
“The factors or drivers of disaster events may already be in place long before a particular event occurs,” Xu said. “The eventual losses depend not only on the magnitude of the hazard but also on what lies along its path.”
The precise timing and scale of an individual collapse may be a matter of probability. In this case, Xu said, an extreme but low-probability event occurred in a location where the consequences were severe.
Mountain environment complicates rescue operations
The same terrain that intensified the mudslide has made search-and-rescue operations extraordinarily difficult.
In mountainous areas, roads are commonly constructed along river valleys because this is often the most practical and economical option. However, rivers, floods and debris flows also follow these valleys. As a result, the infrastructure needed to reach remote communities is frequently located directly in the path of natural hazards.
“This is a universal problem in mountain regions,” Xu said. “The roads and the hazards often follow the same route.”
The mudslide destroyed or severely damaged regular access roads, preventing rescue teams from reaching the affected areas through conventional means. Responders have had to repair roads while simultaneously identifying alternative routes on foot or by air.
The remoteness of the disaster zone has created further logistical challenges. Rescue teams operating at the site need food, equipment, communications and places to rest, but both supplies and usable space are limited. Establishing and sustaining operational bases in such conditions is itself a major task.
Even after rescuers reach the affected area, the unstable environment continues to threaten their safety.
Threat of secondary disasters
Xu identified two major secondary hazards: the possible outburst of barrier lakes and the risk of another collapse from the same glacier or surrounding mountain slopes.
Landslides and debris flows can block rivers, forming temporary natural dams and creating barrier lakes. Because the valley surface remains loose and geologically active, new landslides may continue to occur. If a natural dam fails, the sudden release of impounded water could produce another destructive flood or debris flow.
A further glacier collapse could have similarly serious consequences. Either type of secondary event could strike rescue teams working in the disaster zone, as well as communities downstream.
Rescue personnel have reportedly had to withdraw temporarily from dangerous locations in response to safety alerts. Such withdrawals demonstrate the difficult balance between searching for victims and protecting responders from additional hazards.
Xu said continuous monitoring is therefore essential. Authorities on both sides of the border must closely observe glaciers, unstable slopes, rivers and barrier lakes while ensuring that rescue teams have clear warning and evacuation procedures.
The psychological burden on rescuers
Not all the challenges facing rescue workers are technical or immediately visible.
Xu emphasized the emotional and psychological pressure on those searching through the affected area. Some rescuers may know the missing or deceased personally—as friends, colleagues, acquaintances or members of the same community.
They are also likely to understand the survival prospects of people buried under mud and debris. This knowledge can intensify their grief while they continue carrying out physically demanding and dangerous work.
“The rescuers feel the same shock and grief as the rest of us,” Xu said. “Some are searching for people they knew, while being fully aware of the survival rates and the reality of what they may find.”
At the same time, rescuers are driven by a strong professional and personal sense of duty. Xu described this as an “inner mission” that compels them to continue despite exhaustion, danger and emotional distress.
The response should therefore address not only responders’ physical safety but also their mental health. Psychological assistance, adequate rest and long-term support may be needed for personnel exposed to traumatic scenes and personal loss.
Humanity should guide the cross-border response
Because the disaster crossed an international boundary and affected people of different nationalities, it also raises important questions concerning humanitarian law and policy.
According to Xu, the most immediately relevant principles concern the humane management of the dead and missing, the respectful treatment of their families and the proper handling of bodies, identities and personal information.
These responsibilities become particularly complex in a cross-border emergency. Victims may be citizens of Nepal, China or other countries, while their families may be waiting for information far from the disaster area.
Xu said humanity must remain the central value and fundamental principle of the response. All victims and their families should be treated with dignity, regardless of nationality or which side of the border they are on.
This means conducting searches and identification work carefully, handling human remains respectfully and sharing verified information with families through appropriate channels. Authorities must also avoid unnecessary delays in notifying relatives or transferring remains because of administrative and jurisdictional complications.
The humanitarian principle does not require either country to disregard sovereignty, national security, political interests or border-management responsibilities. Rather, Xu argued that both sides should preserve a neutral humanitarian space in which necessary discussions and negotiations can take place.
Such neutrality can prevent political considerations from obstructing urgent rescue and relief work. It can also support coordination between authorities while ensuring humane care for victims, missing persons and their families.
“Cooperation and coordination in rescue and relief should take priority over more conservative geopolitical considerations,” Xu said. “That does not mean disregarding sovereignty or security. It means maintaining the neutral space necessary for humanitarian discussion and action.”
China–Nepal coordination is a common interest
The physical route of the disaster makes bilateral coordination indispensable. It began with a glacier collapse in Nepal, struck China and then continued farther downstream into Nepal.
Both countries lost lives, both are conducting rescue operations, and both will have to address recovery and reconstruction. Cooperation is therefore not simply a diplomatic choice but a matter of common safety and shared interest, Xu said.
Ongoing coordination has included the exchange of data, satellite imagery and technical assessments. The two sides have also been monitoring upstream areas for signs of further glacier collapses, landslides, barrier-lake failures or floods.
Xu described the monitoring of secondary hazards as one of the most urgent priorities. Another major event would threaten not only rescue teams but also communities that have already suffered from the initial disaster.
Sharing information and alerts, however, is only part of the task. The more difficult challenge is to jointly develop contingency plans for possible secondary disasters.
Such plans should establish how rescue teams on both sides will respond to new warnings, where they will evacuate, which communication channels they will use and how authorities will alert downstream communities. They should also account for circumstances in which damaged infrastructure or interrupted communications prevent conventional warnings from reaching those at risk.
“The difficult part is not necessarily creating a mechanism for sharing monitoring information and alerts,” Xu said. “The challenge is jointly developing contingency plans for rescue teams and communities on both sides in the event of another disaster.”
China has also supported Nepal by providing technical expertise, relief supplies and financial assistance. Xu said such support is appropriate and relevant given the scale of the disaster’s impact on Nepal.
Bilateral cooperation will remain important after search-and-rescue operations end. The two countries will need to discuss infrastructure restoration, livelihood recovery, environmental monitoring and measures to reduce the risk of similar disasters.
International assistance should reflect needs and capacity
Beyond bilateral cooperation, the disaster has drawn wider international attention. Xu said the need for global support should be evaluated by considering two factors: the scale of the affected country’s needs and its capacity to meet those needs.
Some countries can manage a large disaster primarily through domestic resources, while others may require international assistance even during smaller emergencies. The appropriate level of support therefore depends on the specific context rather than the hazard’s magnitude alone.
Nepal is highly exposed to earthquakes, landslides, floods and other natural hazards. Over time, the country has developed considerable experience and capacity in search and rescue, emergency medical assistance and rehabilitation. Those capabilities have been evident in the response to the August 26 disaster, Xu said.
However, the severity and geographical extent of the event may place sustained pressure on Nepal’s available resources. Domestic capacity may be sufficient for some immediate tasks but struggle to meet all the needs associated with relief, rehabilitation and reconstruction.
International assistance should initially respond to the specific requests and priorities identified by Nepal’s government. Countries and humanitarian organizations should avoid sending unsuitable assistance that could burden local logistics or duplicate existing resources.
In the longer term, affected families will need help rebuilding homes, restoring livelihoods and recovering access to essential services. Roads and other infrastructure will have to be reconstructed, while communities may require continuing medical, psychological and financial assistance.
Xu said international support could become even more important during this extended recovery phase than during the initial emergency.
“Rebuilding people’s lives will involve a series of enormous tasks,” Xu said. “Global support is needed and may be needed even more in the longer term.”
Lessons for future Himalayan disasters
The Nepal August 26 Mudslide demonstrates that an extreme disaster cannot be understood simply as an isolated natural event.
The destructive flow lasted only minutes, but the underlying conditions developed over a much longer period. The region’s steep valleys and glacier-covered mountains created the physical setting, while climate-related warming and geological disturbance contributed to instability. The presence of communities, infrastructure and economic activity in the flow’s path then transformed an extreme natural hazard into a major human disaster.
The event also shows how risk in the Himalayas can cross administrative and national boundaries. A glacier collapse in one country can rapidly threaten communities, infrastructure and rescue personnel in another. Monitoring and emergency planning must therefore extend beyond individual jurisdictions.
Xu’s analysis points to several priorities: stronger monitoring of glaciers and unstable slopes, improved early-warning systems, safer mountain infrastructure, joint China–Nepal contingency planning and sustained support for affected communities.
The disaster also reinforces the importance of putting humanity at the center of the response. Respectful management of the dead and missing, timely assistance for families, protection of rescue personnel and cooperation across borders are not secondary concerns. They are essential parts of an effective humanitarian operation.
Ultimately, Xu said, future losses will depend not only on whether extreme natural events occur but also on how governments and communities prepare for them, where infrastructure is built and how quickly countries cooperate when hazards cross their borders.