Grease ice

Grease ice is a very thin, soupy layer of frazil crystals clumped together, which makes the ocean surface resemble an oil slick. Grease ice is the second stage in the formation of solid sea ice after ice floes and then frazil ice.

New sea ice formation takes place throughout the winter in the Arctic. The first ice that forms in a polynya are loose ice crystals called frazil ice. If the level of turbulence is sufficient, the frazil ice will be mixed down into the upper layer and form a surface layer of grease ice.