Frazil ice

From Glossary of Meteorology

frazil ice

  1. An accumulation of frazil in a body of water.

  2. The initial stage of ice formation in turbulent water.

    Frazil ice consists of platelets or discs roughly 1 mm in diameter. These small platelets clump together to form shuga, and eventually (if sufficient open water area exists) form pancake ice. Frazil ice may form in open water leads and around the ice margins in the Arctic, but it is most common in the Antarctic. It may also form in turbulent rivers in winter, particularly in rapids.