What happened in Nepal?
In August 2026, a major glacier and rock collapse occurred in the Langtang Lirung region near the Nepal–China border. A large amount of rock and glacier ice suddenly broke away from the mountain and rushed downhill.
The collapse created a powerful mixture of ice, rocks, water and debris. This rapidly moved through the valley and caused a destructive flood downstream.
But what caused such a massive collapse?
How is climate change connected?
Climate change does not mean that every glacier suddenly melts and causes a flood. The connection is more complicated.
The Himalayan region has been warming rapidly. Higher temperatures can affect glaciers, snow and the frozen ground that helps hold mountain slopes together.
1. Glaciers are losing ice
When temperatures remain higher for longer periods, glaciers lose more ice than they gain. Over many years, this can make glaciers thinner and change the structure of the surrounding mountain landscape.
2. Permafrost can thaw
At high altitudes, water can remain frozen inside cracks in rocks and mountain slopes. This frozen ground is known as permafrost.
When temperatures rise, some of this frozen material can thaw. This can reduce the stability of mountain slopes and make certain areas more vulnerable to rockfalls and collapses.
3. More rain can reach high elevations
A warmer atmosphere can change precipitation patterns. At some high elevations, precipitation that might previously have fallen as snow can instead fall as rain.
Rainwater can enter cracks in rocks and add pressure to already unstable slopes.
Then what happened?
On 26 August 2026, a large section of rock and glacier ice collapsed in the Langtang Lirung area.
The falling material mixed with water, ice, rocks and sediment. It created a fast-moving debris flow that travelled downstream and developed into a destructive flood.
According to scientists from World Weather Attribution, the extreme warming in the region was made more likely and more intense by human-caused climate change.
However, climate change was not the only factor.
The geology of the mountain, existing weaknesses in the rock and other local factors also played important roles. Scientists therefore describe climate change as a factor that can increase the risk of these types of hazards rather than as the single cause of the disaster.
Why should we care?
The Himalayas contain enormous amounts of snow and ice and are an important source of water for millions of people.
As the climate warms, changes in glaciers, snow and frozen mountain landscapes can create new risks — including glacier-related floods, landslides and unstable slopes.
The Nepal disaster is a reminder that climate change is not only about rising temperatures. It can also change the stability of mountain environments and increase the risk of complex natural hazards.
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Sources: World Weather Attribution; Reuters, September 2026.
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