Hudson Bay High Sea

Southern Hudson Bay is a shallow expanse of cold water, fed by rivers draining the surrounding lowlands. Wind and river runoff help drive a broad counterclockwise circulation around the bay, whose waters ultimately leave through Hudson Strait. For much of the year the surface is covered with ice. Ships serving the fur-trading posts depended on the short season of open water; if ice blocked their return through the strait, their crews could be forced to winter on the bay.