This presentation highlights empirical links between rising Arctic baseflow, permafrost thaw, and subsurface water storage. By combining streamflow analysis with new equations linking permafrost thaw to baseflow, we demonstrate that active layer thickness trends can be inferred from streamflow. Results indicate consistent increases in baseflow and active layer thickness across North American Arctic and Subarctic watersheds. These results are corroborated by GRACE satellite water storage trends and are consistent with active layer thickness changes observed in similar regions, signaling the rising importance of subsurface processes for understanding Arctic hydrology under a changing climate.