Snow4Flow: A new NASA airborne mission to measure and model the state and fate of Arctic glaciers

Quantifying the ongoing retreat of glaciers and ice sheets – and projecting their futures – are major societal concerns due to their contribution to sea-level rise and influence on water resources, natural hazards, and associated socioeconomic impacts. However, our ability to confidently project glacier and ice-sheet mass change is often limited by a severe lack of  observations that reliably constrain both their input (snow) and output (flow) mass fluxes. To address these needs, in April 2024 NASA selected Snow4Flow as an Earth Venture Suborbital (EVS-4) mission. Snow4Flow will capture the spatial variability in snow accumulation and ice volume across 4 Arctic and near-Arctic regions that contain hundreds of rapidly changing glaciers to deliver more reliable, societally relevant projections of land-ice change. Our target areas are Alaska and far western Canada, southeastern Greenland, the Canadian High Arctic, and Svalbard. We will perform spatially extensive multi-frequency airborne radar-sounding surveys in March–May 2027–2029, in conjunction with ground-validation campaigns. Snow4Flow will drive foundational improvements to Northern Hemisphere land-ice boundary conditions and forcing data, including orographic precipitation patterns in alpine environments, ice thickness and subglacial topography, and will directly leverage them into state-of-the-art models and projections. All associated software, datasets and model outputs will be rapidly and openly distributed to enable both independent use and assessment, along with portability to other glacierized regions on Earth.