 Most of the pack ice off Newfoundland's northern and eastern shores originates off Labrador.While some of the pack ice off the west coast also comes from the sea off Labrador via the Strait of Belle Isle, most of it originates in the Gulf of St. Lawrence.Beginning in January the pack ice begins to advance south, borne by the Labrador Current until (usually) in April the rate of melting overtakes the rate of advance and the ice retreats northward.