This thesis examines high-latitude fluvial dynamics in the context of changing hydroclimatic conditions, focusing on climate-driven alterations to geomorphological processes in meandering rivers. The study targets rivers in the boreal-subarctic zone, a transitional region between temperate and Arctic climates, where rivers are particularly sensitive to climate-related changes. Climate change is expected to significantly affect fluvial dynamics, altering hydrological regimes and landscape stability. Understanding these interactions is crucial for predicting future sediment fluxes, landscape evolution, and ecological impacts. The research combines hydroclimatic and morphological time-series from boreal-subarctic rivers, field data, remote sensing, and morphodynamic modelling to assess the effects of hydroclimatic shifts. The study focuses on two Finnish rivers with contrasting conditions: the boreal Oulankajoki and the subarctic Pulmankijoki. The thesis includes three case studies: i) time-series analysis of hydroclimatic and morphological data to assess climate-driven changes in meander migration and sediment transports seasonality, ii) morphodynamic modelling of one hydrological year to evaluate temporal shift in sediment connectivity, and iii) modelling of morphological responses to variability in flood events. Key findings indicate that spring floods, once the primary drivers of sediment transport, are losing prominence due to earlier snowmelt, milder winters, and increased rainfall in other seasons. This shift has resulted in more event-driven sediment connectivity, with heightened variability in transport processes and morphological responses. Multi-peaking floods, prolonged thaw periods, and intensified rainfall are emerging as critical drivers of sediment dynamics. The study underscores the importance of sediment connectivity and the need for high-resolution monitoring and modelling in a changing environment. The findings demonstrate that while large-scale patterns of change are consistent, their impacts can vary significantly between catchments, providing crucial insights for predicting sediment loads, evaluating landscape resilience, and informing sustainable river management.