in rough water, fresh sea ice is formed by the cooling of the ocean as heat is lost into the atmosphere. the uppermost layer of the ocean is supercooled to slightly below the freezing point, at which time tiny ice platelets (frazil ice) form. with time, this process leads to a mushy surface layer, known as grease ice. frazil ice formation may also be started by snowfall, rather than supercooling. waves and wind then act to compress these ice particles into larger plates, of several meters in diameter, called pancake ice. these float on the ocean surface, and collide with one another, forming upturned edges. in time, the pancake ice plates may themselves be rafted over one another or frozen together into a more solid ice cover, known as consolidated pancake ice. such ice has a very rough appearance on top and bottom.