A thin, elastic crust of ice, up to 10 cm thick.
A thin, elastic crust of ice, up to 10 cm thick, with a matte surface. Can easily be deformed (bending, not breaking) by wind or wave action. Lateral pressure can result in overthrust and underthrust. Dark nilas is up to 5 cm thick and very dark; light nilas is 5 – 10 cm thick and somewhat lighter. Read here how sea ice is formed.