Observations of the Great Whale River plume in the coastal waters of Hudson Bay, Canada, during late winter and early spring during four differnt years showed its area to vary as a power of the discharge. The under-ice plume geometry were related to elapsed time since ice formation and low-frequency variability of the coastal circulation. The strength and orientation of the coastal motion low-pressure systems over Hudson Bay is thought to generate a progressive edge wave in the absence of direct wind forcing. The amplitude of the low-frequency variations in coastal ciruclation decreased with the increasing spatial extent of the landfast ice in the study area. ¿ American Geophysical Union 1987