1 of ice, break up in the spring and move with the current until melted.
1743  (1949)  I have Known the Ice when going out of the Rivers, to appear Like a wood or grove of trees with the perdigious Quantity of wood, which has been brought of the shores by the water and Ice, when these floods has happn'd.
1904  It [the river ice] appeared placid . . . but the woodsman's practised eye perceived that it might break up, or "go out," at any moment.
1963  I met Kenai Creek, its ice covered with muddy water and odd flotsam, flowing upstream against itself, and in the distance was a muttering as if of thunder--The Sikanni Chief [River] had "gone out."
2 leave the North to visit or return to more settled areas.