Frazil

It has been suggested that it may be due to the accumulation of frazil or anchor-ice.

The greater the surface of the swift open water, the greater the quantity of frazil made in a minute, hour, or day. Every open rapid is, in ‘zero weather’, a frazil-factory.

Following currents that flow across the Bering and Chukchi shelves, microplastics from the Pacific that arrive in Arctic waters are gathered up by the tiny crystals that clump together to form ‘frazil’ (the gloss of soft ice that forms on the surface of the water) and then are bound into the sea ice.