Stacked blocks of broken ice produced by intense piling.
Stacked blocks of broken ice produced by intense piling. These small hillocks are produced by stresses and shearing forces between ice floes. Over time, they can be changed by snow drift, summertime melting processes, and the effects of sunlight. Fields of pack-ice hummocks often consist of random, chaotically distributed structures. The part of a hummock that extends underwater is referred to as the bummock.