noun
ice field
A large expanse of sea ice, often formed by drift ice. Used in geographical and meteorological contexts.
オホーツク海には冬になると広大な流氷野が広がる。
In winter, a vast ice field spreads across the Sea of Okhotsk.
氷原 is a more general term for an ice field or ice sheet, not necessarily formed by drift ice.
Compound of 流氷 (drift ice) and 野 (field, plain).