What we know
- Online Khabar English reported that unusually high temperatures preceded the August 26 glacier collapse in Rasuwa.
- Average temperatures at the glacier reached approximately 5 degrees Celsius between August 21 and 26.
- The 55 years of historical weather data show temperatures at this site had never exceeded 4 degrees Celsius during this specific calendar window.
- Experts suggest that thawing permafrost and intense snowmelt weakened the mountain slope, leading to the collapse.
What this means if you are travelling
- Travellers planning to trek in the Langtang and Rasuwa regions should monitor local weather updates and check with their guides regarding slope stability.
- The collapse occurred in a high-altitude area of Rasuwa, meaning popular lower-elevation routes are not directly blocked but remain subject to local safety assessments.
- The border crossing area of Timure was affected by the subsequent Bhotekoshi flood, so overland travellers to China must verify current road and border access with their operators.
- Trekkers heading to other regions of Nepal, such as Annapurna or Everest, are unaffected by this specific localized event.
A scientific analysis of meteorological data has revealed that the high-altitude glacier whose collapse triggered deadly floods on August 26 experienced unprecedented temperatures in the days leading up to the disaster. According to reporting by Online Khabar English, the glacier is situated at an elevation of 5200 metres in the Rasuwa district and experienced an average temperature of approximately 5 degrees Celsius between August 21 and August 26.
This sudden warming trend is highly unusual for the region during late August. Historical meteorological records spanning more than 55 years show that temperatures at this specific location had never surpassed 4 degrees Celsius during this exact timeframe, highlighting the exceptional nature of the pre-collapse weather patterns.
Scientific Findings on the Temperature Spikes
The localized temperature estimates were reconstructed by Robert Rohde, the chief scientist at the California-based independent climate research organization Berkeley Earth. Rohde reported that the average temperature at the site of the collapse has risen by about 1.8 degrees Celsius since the middle of the 20th century.
According to data from the European Union Copernicus climate monitoring programme analysed by AFP, the collapse took place during the fourth-hottest summer recorded in the Langtang region since 1970. Without the broader trends of climate warming, a temperature pattern of this severity would likely occur only once every several thousand years.
How Warm Weather Destabilises Mountain Slopes
Climatologists and glaciologists have explained that extreme heat can compromise the structural integrity of high-altitude rock faces. French climatologist Valerie Masson-Delmotte noted that these warm conditions can cause permafrost to thaw, which acts like ice cement holding mountain slopes together.
In addition to thawing permafrost, satellite images captured significant snowmelt before the disaster. Glaciologist Etienne Berthier from France CNRS research agency indicated that the resulting meltwater could have run into cracks in the mountain, further destabilising the slope and contributing to the eventual failure.
- Permafrost thaw weakens the natural ice cement holding high-altitude rock faces together.
- Rapid snowmelt creates water that infiltrates rock fractures, increasing internal pressure.
- Slight structural movements had been detected in the mountain during the years preceding the actual collapse.
What This Means for Trekkers and Travellers
For international travellers currently in Nepal or planning a trip to the Langtang region, safety depends on understanding localized risks. The immediate flooding affected the Bhotekoshi river system and the border settlement of Timure. Travellers must consult with their trekking operators to confirm the safety of trails in these specific river valleys.
While the scientific community cautions that high temperatures alone do not automatically trigger immediate collapses, the overall instability of slopes during exceptionally warm periods is a factor to watch. Trekkers are advised to remain on established paths, avoid resting directly beneath steep rock walls, and monitor regional weather reports closely.
Reported by
This update summarises reporting from the outlets below and adds our own planning guidance. Follow the links for the original reports.
Questions travellers are asking
Where did the glacier collapse take place?
The glacier collapse occurred at an altitude of 5,200 metres in the Rasuwa district of Nepal, within the Langtang region, affecting areas along the Bhotekoshi river including Timure.
What temperature anomalies were recorded before the flood?
Between August 21 and August 26, average temperatures at the glacier reached about 5 degrees Celsius. This exceeded the 4 degrees Celsius limit that had held for more than 55 years of recorded data.
Was the disaster directly caused by climate change?
While scientists link the unusual heat to climate change, geomorphologists state that temperature acts as a trigger only when a rock face is already at its tipping point. Researchers are still studying how prior mountain movements interacted with the temperature spike.
Are other trekking routes in Nepal affected by this event?
No. This was a localized geographic event in the Rasuwa and Langtang region. Other major trekking destinations such as the Annapurna region and the Everest region remain unaffected by this specific glacier collapse.