• Workshop Agenda

Local Host: John Pomeroy, University of Saskatchewan

The 2026 Annual Workshop of the International Network for Alpine Research Catchment Hydrology (INARCH) was held September 8–10 at the University of Calgary’s Kananaskis Centre (the Barrier Lake field station) in Alberta, Canada, bringing together 37 participants from Canada, China, Chile, Nepal, Spain, the United Kingdom, and the United States. One additional presentation was delivered remotely from China, and seven participants joined online for the final COPE session. The meeting marked an important point as INARCH approaches completion of Phase II (2021–2026) and prepares for renewal as a GEWEX Cross-Cutting Project. INARCH now connects more than 60 scientists and 43 experimental research basins across 19 countries and six continents.

Scientific presentations highlighted major advances in mountain observations and remote sensing, integrated observation–modelling systems, and increasingly sophisticated hydrological and cryospheric models. New observing technologies and observatories are expanding measurements of snowfall, snow cover, glaciers, groundwater, ecosystems and hydrological processes, including in previously data-sparse mountain regions. Modelling developments included higher-resolution snow redistribution, data assimilation, AI applications, improved representation of hydrological processes, including water quality and isotopic signatures, and increasingly coupled snow–soil–vegetation–groundwater–runoff systems. Problems in forcing data for hydrological modelling in mountain basins were identified as was the unnecessary uncertainty introduced by use of temperature index models of glacier ablation.  Participants also examined the consequences of snow drought, declining snowpacks and transitions from snow to rain, which are already altering mountain runoff, ecosystems and downstream water availability. Observations from the Canadian Rockies, for example, document ongoing cryospheric retreat and associated impacts on mountain hydrometeorology, groundwater, runoff processes, evapotranspiration and downstream hydrology.

A particularly important focus was the August 2026 Nepal–China flood, a catastrophic cascading event involving glacier and rock collapse and a rapidly propagating flood wave. The event demonstrated the limitations of conventional stream-gauge-based warning systems and reinforced the need for integrated cryosphere–hydrology observations and prediction, rapid remote sensing, transboundary data sharing and community-based early warning. The workshop also advanced INARCH’s Common Observing Period Experiment (COPE) from its observational phase toward coordinated data publication and diagnostic modelling. COPE has established an international mountain model testbed involving more than 15 modelling frameworks, and WaterNet is being developed as the pathway for organizing and accessing COPE sites, datasets and models.

The workshop included extensive scientific discussion and a field excursion to the Fortress Mountain Research Basin, providing participants with direct exposure to long-term Canadian Rockies observations and ongoing process studies. The meeting concluded that rapid cryospheric decline is producing substantial changes in mountain hydrological function, making improved observation and prediction increasingly urgent.  Tipping points in hydrological function were identified in some basins, but it is unclear whether they have yet been crossed.  More comparison of basin responses to climate variability using elasticity analysis and evaluation of extreme events will help complete the COPE analysis. INARCH will continue its international coordination through COPE and contribute its coupled observation and prediction capabilities to the UN’s Decade of Action for Cryospheric Sciences (2025–2034). The group also identified Nepal as the intended location for the next INARCH meeting, hosted by Dr. Dhiraj Pradhananga of Tribhuvan University and The Small Earth Nepal.

Participants of the 2026 annual workshop at the Fortress Ridge meteorological station within the Fortress Mountain Research Basin, Kananaskis, Alberta, Canada (September 9, 2026).