Sea ice that has survived at least one summer's melt. Most topographic features on old ice are smoother than those on first-year ice. May be subdivided into second-year ice and multiyear ice.
Sea ice terminology describing sea ice which has survived at least one summer's melt. The surface of old ice is generally smoother than first-year ice. Old ice may be subdivided into second-year ice a
nd multi-year ice.
Sea ice which has survived at least one summer's melt; typical thickness up to 3m or more. It is subdivided into residual first-year ice, second-year ice and multi-year ice.
Sea ice more than 2-years-old, up to 3 meters (10 feet) or more thick; hummocks on old ice are even smoother than in second-year ice, and the ice is almost salt-free; when old ice is bare of snow, it
is blue and lacks the greenish tint of second-year ice.
Sea ice more than two years old, up to 3 m or more thick. Hummocks on old ice are even smoother than in second-year ice, and the ice is almost salt-free. When old ice is bare of snow, it is blue and l
acks the greenish tint of second-year ice.