nilas

One of the first phases in the life cycle of sea ice is nilas, a thin elastic crust that forms on calm water. It has a matte surface and is easily bent by waves. The word nilas comes from the Russian language in which it is pronounced “knee-lass.” Related to nilas is grease ice, a soupy layer of crystals that forms on the water’s surface after frazil ice, the first small spicules of sea ice to take shape, begins to consolidate. Like nilas, grease ice reflects little light, giving the sea an oily appearance. Both types are viscous and fluid, not yet constituting hard pieces of floating ice. As nilas moves before the wind or with the current it may turn to pancake ice— loose, mostly circular, pancake-shaped pieces whose outer rims are raised slightly, due to their rotating and bumping into one another. Pancake ice is sometimes called lily-pad ice, because of its resemblance to the green pads of these water plants. Fields of pancake ice may eventually grow large enough to become floes, and then consolidated pack ice—floes that have joined together in a massive, floating plain.

Gretchen Legler