Three ice cores drilled successfully in the Himalaya to reconstruct high altitude snowfall

Deployment by helicopter on the glacier. Photo: Mariusz Potocki, University of Maine

A team of scientists from Utrecht University, GFZ Potsdam, the University of Rennes, the University of Maine and Tribhuvan University returned from a successful research expedition in the Nepalese Himalaya. The main objective of the team was to extract ice cores at the Ganchempo glacier at an altitude of 5,700 meter above sea level. This expedition was part of the ERC DROP project, led by Walter Immerzeel, on understanding the drivers of high-altitude precipitation.

After nearly two weeks of acclimatization, the first attempt to deploy the team to the icecore site failed and due to high windspeeds the helicopter could not land. A second attempt was more successful and during three days of extremely tough conditions, including -21 degrees nighttime temperature and 1.5 meter of fresh snow on top of the ice, the team managed to extract three high quality icecores, each with a different objective:

  • One core will be used to link high-resolution snow deposits to a large, automated precipitation isotope sampling campaign conducted during the 2025 pre-monsoon and monsoon season.
  • The second core will be used to study the variability of rain and snowfall over the last 10 to 20 monsoon seasons.
  • Finally, the third core aims to study the variation of 129-iodine in precipitation over the last 10 to 20 years and to examine this artificial isotope as a potential tracer of the water cycle in watercourses and river runoff. 

Although I have climbed many peaks in the Alps, working in the Himalaya at this altitude was one of the most challenging but also one of the most beautiful things I ever did

Landing at the icecore site. Photo : Mario Potocki, University of Maine

For the three PhDs in the team (Raeven van den Acker, Aris Kwadijk and Emma Davies) the expedition was a truly unique experience. “Although I have climbed many peaks in the Alps, working in the Himalaya at this altitude was one of the most challenging but also one of the most beautiful things I ever did,” according to Aris Kwadijk. 

In such conditions, it is essential to collaborate closely and communicate openly between scientists, guides, sherpas and the helicopter staff. “The dynamics in the team were really nice, even though the conditions were very difficult sometimes. I found it interesting to understand how this works and what everyone’s role is in a team under such circumstances,” says Raeven van den Acker.

Preparation and packaging of samples. Photo: Mariusz Potocki, University of Maine

Now the next phase starts, all samples will be shipped to the United States where they will be analyzed in the specialized lab of the University of Maine. This work will be led by Mariusz Potocki and Paul Mayewski. Each sample will be analyzed for stable isotopes and a range of major and trace elements. “I cannot wait to see the first results and hopefully we will see a seasonal cycle and will these data help us understand the changes in the snowfall dynamics at high altitude over the last decades,” says Walter Immerzeel.

Research team at Yala glacier. Photo : Walter Immerzeel