Cryosphere field expedition to Hidden Valley, Mustang, Nepal

About the expedition

This year’s expedition to Rikha Samba Glacier in the Hidden Valley, Lower Mustang, Nepal, will collect field-based data and maintain the glacier’s mass-balance network, weather stations, and other monitoring systems.
The expedition will bring together experts and participants from ICIMOD, Tribhuvan University (TU), and IIT Indore, India. Alongside routine monitoring, the field activity will provide hands-on training and capacity-building opportunities for participating members from TU, Nepal and IIT Indore, India.

The expedition will monitor all three components of the cryosphere: snow, glaciers, permafrost. Activities will include snow-depth, snow-density and precipitation measurements; maintenance and measurement of the glacier mass-balance stake network; operation of weather stations; and retrieval of permafrost temperature data from existing sensors.

The field observations will strengthen long-term cryosphere monitoring while contributing to a better understanding of Rikha Samba Glacier and its response to a changing climate.

Objectives for the Expedition

Snow Monitoring:

• Assess the operational status of the snow stations at Yak Kharka and Kalopani.
•  Conduct snow measurements at previously installed NVE snow stations to validate existing data.

Glacier Monitoring:

• Maintain the off-glacier weather station and download data
• Maintain the glacier mass balance stake network, measure existing stakes and install new stakes where needed
• Conduct snow measurements at accumulation stakes, including snow probing, snow profile analysis, and density measurements
•  Capture repeat photographs of the glacier terminus from the established photo point.

Permafrost Monitoring:

• Maintain the existing climate station in Hidden Valley and download recorded data.
• Retrieve data from nine Tidbit V2 temperature loggers installed along the route from Kalapani to Hidden Valley.

Expected Outcomes

Strengthen cryosphere monitoring: updated and operational monitoring systems for snow, glaciers, and permafrost across the Hidden Valley contributing consistent data, supporting long term observation of cryosphere change in the Hidden Valley.
Expanded field-based datasets: new and updated observations of snow depth, glacier mass balance, permafrost temperature, and meteorological conditions contributing to improved understanding of cryosphere dynamics and climate related changes

Enhanced institutional capacity and collaboration: strengthened partnerships, knowledge exchange and collaboration among ICIMOD and partner research institutions.

Funding and acknowledgements

The expedition is organised by ICIMOD’s Cryosphere Intervention under the Climate and Environment Risks Strategic Group, with support from the Swiss Agency for Development and Cooperation (SDC).
ICIMOD acknowledges Tribhuvan University, Nepal for its collaboration and technical contribution to the field activity.

Background

Rikha Samba glacier is one of the benchmark glaciers of Nepal jointly monitored by ICIMOD and partners. The glacier is among the most extensively studied glaciers in the central Himalayas. Scientific observations of the glacier date back to the 1970s, including research by Japanese glaciologists through the Glaciological Expedition to Nepal (GEN). ICIMOD has conducted annual monitoring at Rikha Samba since 2011, including glacier mass-balance measurements and observations from weather stations on and around the glacier.

Long-term field observations provide essential evidence for understanding glacier change and help validate models used to assess future cryosphere conditions. Data collected at Rikha Samba therefore contribute to both local understanding of glacier dynamics and broader efforts to monitor changes across the Hindu Kush Himalaya.

ICIMOD’s measurements show that Rikha Samba Glacier has experienced sustained mass loss, with an average mass-balance trend of approximately- 0.39 ± 0.32 metres water equivalent per year. Continued monitoring is essential for tracking these changes and understanding their implications in a warming climate.