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Assessing impact of snow sublimation for hydropower production in Norway (SnowSub)

Hydropower has a significant role in the Norwegian energy system, and deliver green energy to the society. Snow is the largest reservoir in many hydropower systems. A snow reservoir is leaking water to the air by a process known as sublimation, which result in that the snow is lost from hydropower production. But what is the actual amount of “lost snow”? The SnowSub project aims to answer this question.

In Norway, hydropower is the main source for electricity. Most of it is produced by melting snow, but not all snow will end up as water. Snow can have a convection between solid and gaseous form, without an intermediate liquid stage. Photo: SnowSub/gK

In Norway, hydropower is the main source for electricity. Most of it is produced by melting snow, but not all snow will end up as water. Snow can have a convection between solid and gaseous form, without an intermediate liquid stage. Photo: SnowSub/gK

About the project

Until recently, Norway did not have any continuous eddy covariance measurements, which provide in-situ evapotranspiration and sublimation observations of reservoars of snow. This knowledge gap contributes to uncertainties in forecasted inflow into hydropower reservoirs during the snow melt season. Hydrologic modelling is fundamental and critically important for water resource managers and hydropower operators to forecast inflow. Currently, Snowpack models within operational hydrological software have very poor (if any) accounting of the sublimation process.

Flux observations will directly contribute to operational model development, parameterization and validation. This is expected to result in improved scheduling of hydropower production. To have more predictive control over the losses through enhanced hydrological modelling would create value through improved ability to optimize production and “maintain stability, flexibility and security of supply in the energy system of the future”.  An overall better understanding of snow processes will also lead to improved prediction of floods contributing to safety in the downstream regions. In SnowSub we aims to consolidate, structure and develop snow research in the operational environments by engaging regional scale power production companies, experts in hydrologic modelling and field observations in a joint effort to assess model state, refine and validate forecasting routines.

The focus in SnowSub is particularly on Norwegian hydropower production, but with a long-term goal to reduce uncertainties in inflow forecasts within other regions where snowmelt contributes to streamflow. Improving hydropower production scheduling is important for transition towards zero-emission societies. 

Objectives

The goals we want to reach with the SnowSub research project are particularly these: 

  • To quantify sublimation losses based on field observations at five flux sites in Norway; 
  • To develop and parameterize a sublimation subroutine (including interception from canopy) based on field observations; 
  • To develop a new energy balance snow routine that includes the sublimation subroutine, in the operational hydrological software (Shyft); 
  • To test and validate the new routine for selected catchments and at the regional scale in collaboration with the hydropower companies Stakraft and Skagerak-Energi; 
  • To communicate results to the wider research and user community.
  • To Enhance cooperation between research institutions and industry towards zero emission society

Financing

The project acronym is SnowSub, with the full name 'Assessing impact of snow sublimation for hydropower production in Norway'. The project is funded as a Collaborative and Knowledge-building Project by the Research Council of Norway, with NFR project number 336621.

The project period for the SnowSub project is from March 2023 until August 2026.

Cooperation

The project is done in cooperation with researchers from the University of Oslo, Norway and the University of Oulu, Finland and is in collaboration with researchers and professionals from the Norwegian research institutions and companies listed below:

Publications

  • Dar, Shaakir; Silantyeva, Olga; Ala-aho, Pertti; Walter, Benjamin; Hulth, John & Hyöky, Valtteri [Show all 8 contributors for this article] (2026). Snow Structure Modulates the Isotopic Imprint of Sublimation. EGUsphere. doi: 10.5194/egusphere-2026-2589. Full text in Research Archive
  • Huang, Shaochun; Silantyeva, Olga; Gelati, Emiliano; Yilmaz, Yeliz A.; Engeland, Kolbjørn & Tallaksen, Lena M. (2026). Can we better constrain evapotranspiration estimates in data scarce cold regions? Application of a discharge-constrained modelling framework in Norwegian catchments. Journal of Hydrology Regional Studies. 67, p. 103850–103850. doi: 10.1016/j.ejrh.2026.103850. Full text in Research Archive
  • Silantyeva, Olga; Huang, Shaochun & Xu, Chong-Yu (2025). Evaluating Flexible Configurations of the Shyft Hydrologic Model Framework Across Mainland Norway. Hydrology and Earth System Sciences Discussions (HESSD). ISSN 1812-2116. doi: 10.5194/egusphere-2025-4071. Full text in Research Archive

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  • Silantyeva, Olga & Helset, Sigbjørn (2026). Shyft FSM2 Implementation. doi: https:/gitlab.com/shyft-os/shyft. Full text in Research Archive
  • Silantyeva, Olga; Huang, Shaochun & Xu, Chong-Yu (2026). Evaluating flexible process-based hydrological configurations against data-driven benchmarks: a large-sample study across 109 Norwegian catchments. doi: https:/acrobat.adobe.com/id/urn:aaid:sc:EU:15b5965a-cc8b-44c2-ba59-2523cca43137. Full text in Research Archive
  • Silantyeva, Olga; Huang, Shaochun & Xu, Chong-Yu (2026). Benchmarking flexible modelling framework Shyft across mainland Norway. doi: 10.5194/egusphere-egu26-22432. Full text in Research Archive
  • Ahlbäck, Malin; Pirk, Norbert; Tallaksen, Lena M. & Silantyeva, Olga (2025). Temporal Dynamics and Hydrological Impacts of Snow-Atmosphere Vapor Exchanges in a High-Altitude Catchment. doi: https:/www.hydrologiraadet.no/wp-content/uploads/2025/08/AbstractsLillehammer2025_210825.pdf. Full text in Research Archive
  • Valseth, Kristen Joy; Valnes, Lars Magnus; Silantyeva, Olga; Lappegard, Gaute & Mardal, Kent-Andre (2025). CAMELS-Nordic, a large-scale hydrometeorological and catchment properties dataset for Norway and Sweden. doi: https:/www.hydrologiraadet.no/wp-content/uploads/2025/08/AbstractsLillehammer2025_210825.pdf. Full text in Research Archive
  • Silantyeva, Olga; Ahlbäck, Malin & Dar, Shaakir (2025). Assessing snow sublimation in Norway: insights from field and laboratory work of SnowSub project. doi: https:/www.hydrologiraadet.no/wp-content/uploads/2025/08/AbstractsLillehammer2025_210825.pdf. Full text in Research Archive
  • Huang, Shaochun; Silantyeva, Olga; Gelati, Emiliano; Yilmaz, Yeliz A.; Engeland, Kolbjørn & Tallaksen, Lena M. (2025). Quantifying the uncertainty of evapotranspiration estimates for unregulated Norwegian catchments using multiple hydrological models and remote sensing products. doi: 10.5194/egusphere-egu25-14913. Full text in Research Archive
  • Valseth, Kristen Joy; Valnes, Lars Magnus; Lappegard, Gaute; Silantyeva, Olga & Mardal, Kent-Andre (2025). Development of CAMELS-Nordic, a large-scale hydrometeorological and catchment properties dataset for Norway and Sweden. doi: 10.5194/egusphere-egu25-10411. Full text in Research Archive
  • Ahlbäck, Malin & Huang, Shaochun (2025). Assessing snow sublimation in Norway: Lessons learned from field and laboratory work of SnowSub project. doi: https:/www.hydrologiraadet.no/wp-content/uploads/2025/08/AbstractsLillehammer2025_210825.pdf. Full text in Research Archive
  • Silantyeva, Olga; Ahlbäck, Malin; Yilmaz, Yeliz A.; Tallaksen, Lena M.; Lappegard, Gaute & Erlandsen, Helene B. [Show all 11 contributors for this article] (2024). SnowSub: Assessing snow sublimation for hydropower production in Norway. Project results at Snow Bridges workshop. Full text in Research Archive
  • Ahlbäck, Malin (2024). Assessing the impact of sublimation for hydrologic modelling. Full text in Research Archive
  • Silantyeva, Olga (2024). Shyft development/usage at UiO. SnowSub project dissemination for Statkraft. Full text in Research Archive
  • Silantyeva, Olga (2024). Shyft development/usage at UiO for Skagerak. Full text in Research Archive
  • Yilmaz, Yeliz A.; Aalstad, Kristoffer; Filhol, Simon; Gascoin, Simon; Pirk, Norbert & Remmers, Janneke [Show all 9 contributors for this article] (2024). Leveraging Earth observations to model snow cover dynamics over Scandinavia. Full text in Research Archive
  • Ahlbäck, Malin; Pirk, Norbert; Tallaksen, Lena M. & Silantyeva, Olga (2024). Assessing the impact of sublimation for hydrological forecasting. Full text in Research Archive
  • Treichler, Désirée; Filhol, Simon; Mazzolini, Marco; Yilmaz, Yeliz A. & Silantyeva, Olga (2024). UiO’s snow field sites, measurements, remotely sensed datasets, and climate container. Full text in Research Archive
  • Ahlbäck, Malin (2024). Assessing the impact of sublimation for hydrological modelling. Full text in Research Archive
  • Silantyeva, Olga (2023). SnowSub: Assessing snow sublimation for hydropower production in Norway. Project presentation at NVE seminar series. Full text in Research Archive
  • Silantyeva, Olga (2023). SnowSub: Assessing snow sublimation for hydropower production in Norway. Project kick-off presentation. Full text in Research Archive
  • Silantyeva, Olga (2023). SnowSub: Assessing snow sublimation for hydropower production in Norway. Project presentation at Latice Annual Meeting. Full text in Research Archive
  • Silantyeva, Olga (2023). SnowSub project and Cold Climate Container at UiO. Full text in Research Archive

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Published Nov. 25, 2022 5:29 PM - Last modified Mar. 7, 2025 9:35 AM

Contact

Olga Silantyeva, Postdoctoral Fellow and Project Leader

Lena M. Tallaksen, Professor (co-Lead) & Kolbjørn Engeland, Researcher (co-Lead)

Participants

Detailed list of participants