Our understanding of the effects of ice on channel morphodynamics and bedload transport in northern rivers, frozen for several months, are hindered by the difficulties of ‘seeing’ through the ice. We use continuous seismic records of a small network at the Sävar River in northern Sweden to interpret processes and quantify water and sediment fluxes. We apply a seismic inversion approach to determine seasonal differences in hydraulics and bedload sediment transport under ice-covered vs. open-channel flow conditions and provide a first-order estimation of sediment flux in that Fennoscandian river. Analysis of seismic signals of ice-cracking support our visual interpretation of ice break-up timing and the main ice break-up mechanism as thermal rather than mechanical. Waveform data are available from the GEOFON data centre, under network code 8E, and are available under CC-BY 4.0 license.