Explained: Why Nepal is so vulnerable to nature's destructive forces

Nepal flash floods: From earthquakes and landslides to flash floods and glacial hazards, Nepal's geography and a warming climate are creating a growing challenge for people and infrastructure

A devastating flash flood swept through parts of Nepal along its border with Tibet on Wednesday, killing more than 160 people and leaving at least 1,000 missing including 177 from India. According to the United States Geological Survey (USGS), a collapse of ice and rock high in the Himalayas sent a sudden surge of water, mud and debris down the Lhende and Bhote Koshi river systems, destroying homes, roads, bridges and power projects.

 

The disaster is the latest reminder of how exposed Nepal is to natural hazards. But why does a country of just 147,516 sq km face such a wide range of risks?

 

Geography is the biggest reason

Nepal is squeezed between the Himalayas to the north and the plains bordering India to the south. From the Terai plains at around 60 metres above sea level, the land rises sharply to Mount Everest at 8,848.86 metres. The north-south distance is only about 150 to 250 km.

 

This steep terrain means water and loose rock can move rapidly downhill. More than 6,000 rivers and rivulets flow through the country, many originating in the Himalayas, and swell during the June-September monsoon.

 

The country's earthquake risk comes from the same geological setting. The mountains themselves are also young in geological terms and are still being pushed upwards as the Indian and Eurasian plates collide, making the Himalayas one of the world's most seismically active regions. The 7.8-magnitude Gorkha earthquake in April 2015 killed about 9,000 people and triggered thousands of landslides. USGS researchers later mapped about 25,000 earthquake-triggered landslides across Nepal and China.

 

Nepal's geology department identifies the country's varied and faulted terrain as a key feature of its landscape, while its disaster-risk assessment points to steep slopes, fragile geology and intense rainfall as major landslide triggers. Road construction, deforestation and poorly planned development can further increase the risk. 

Climate change is adding a new layer of risk

Nepal's natural hazards are being compounded by a warming climate. Rising temperatures are accelerating glacier melt and changing conditions at high altitudes. As glaciers retreat, glacial lakes can form behind natural dams of rock and debris. If these dams fail, large volumes of water can rush downstream suddenly, causing glacial lake outburst floods (GLOFs). Warming and more intense rainfall can destabilise ice, rock and slopes, increasing the likelihood of landslides, avalanches and flash floods. The World Bank says rising temperatures are increasing the risk of GLOFs in Nepal.

 

Nepal has already seen how these risks can combine. In June 2021, heavy rain in the Melamchi watershed triggered flooding, landslides and massive debris flows, causing extensive damage to homes and infrastructure. 

Development can amplify the danger

Natural hazards become disasters when they hit people, homes and infrastructure. In Nepal, much of that infrastructure has to be built through difficult mountain terrain. Roads are often cut into steep slopes. Towns and villages have developed along river valleys because flat land is scarce. Hydropower projects, which are important to Nepal's economy, are also concentrated around rivers and therefore exposed to floods, landslides and debris flows.

 

Nepal's own disaster-risk assessment points to deforestation, encroachment on vulnerable slopes and unplanned construction of roads and other infrastructure as factors that can increase landslide risk.

 

The country has seen repeated examples of this vulnerability. The 2015 earthquake showed the scale of seismic risk. The 2021 Melamchi disaster demonstrated how intense rainfall can combine with landslides and river flows. The September 2024 floods and landslides caused estimated losses of more than 46.6 billion Nepalese rupees, according to the World Bank's April 2025 Nepal Development Update. AALSO READ: Glacial collapse triggered Nepal flash floods, not earthquake: USGS

Can Nepal reduce the risk?

Nepal cannot prevent earthquakes, stop the monsoon or hold back the Himalayas. What it can do is reduce the damage when hazards occur. The country has been strengthening its disaster preparedness, including through early-warning systems, risk mapping and monitoring of multiple hazards. 

 

The National Disaster Risk Reduction and Management Authority says Nepal has moved from flood-specific warnings towards a multi-hazard early-warning system, covering risks including floods, landslides, earthquakes and glacier-related hazards. Its system brings together hazard monitoring, forecasting, warning dissemination and preparedness.

 

The country has also expanded hydrometeorological monitoring and flood-warning capabilities. The World Bank says improvements in weather forecasting and flood warnings have made alerts more accurate and timely, while Nepal's National Adaptation Plan includes early intelligence on potential disasters as part of its climate-resilience strategy.

 

Disaster preparedness is also being supported through changes in policy and financing. In 2024, the World Bank approved $150 million in contingent financing for Nepal to strengthen disaster response, early-warning systems and risk-informed investment in critical infrastructure. The challenge is that Nepal faces several hazards that can occur together or trigger one another. Its disaster-management system therefore increasingly focuses on multi-hazard monitoring and preparedness, alongside measures to make infrastructure and communities more resilient.