pressure ice

A general term for ice whose surface has been deformed by stress generated by wind and currents, pressure ice includes pieces of ice squeezed against the shore, or thrust up against one another—ice that is forced upward or downward. Pressure ice may be rafted, hummocked, or tented, commonly to heights (or depths) of thirty feet or more. (The underside of a mound or hillock of pressure ice is called a bummock.) Norwegian explorer Fritjof Nansen, in his narrative of travels in the Arctic, Farthest North, writes of his ship, the Fram, amid ice floes under the strain of pressure: “The ice is restless, and has pressed a good deal to-day again. It begins with a gentle crack and moan along the side of the ship, which gradually sounds louder in every key. Now it is a high plaintive tone, now it is a grumble, now it is a snarl, and the ship gives a start up. The noise steadily grows till it is like all the pipes of an organ; the ship trembles and shakes, and rises by fits and starts, or is sometimes gently lifted.” Nansen called these episodes “squeezings,” and the ridges that resulted from them as “ugly sights,” one particularly menacing one “like a high frozen wave.”

Gretchen Legler