Big Floe

A big floe is a sea-ice floe between 500 and 2,000 m across, one size class in the WMO Sea-Ice Nomenclature (WMO No. 259). The nomenclature ranks floes from small (20 to 100 m) through medium (100 to 500 m), big (500 to 2,000 m), and vast (2 to 10 km) to giant (over 10 km). Floe-size class governs ship maneuverability and the loads a hull meets: a big floe cannot be deflected or split as readily as a medium floe, so an icebreaker may ram or skirt it. Ice analysts record the dominant floe class on charts alongside concentration and stage of development.