Polar pack ice, in contrast to slob ice. See also ice-field and pressure ridge. "...Meanwhile, the Polar Pack (the ever-present ice of the Arctic) presses southward behind the local ice. Its heavy floes are blue and as much as five feet thick. It is dense ice, frequently covered with gravel, mute testimony to its assaults upon the land on its southward journey. It is rugged, jagged, and altogether intimidating." --Cassie Brown with Harold Horwood, Death on the Ice: The Great Newfoundland Sealing Disaster of 1914, Doubleday Canada, 1972.