That's grease ice. It looks like oil on the water. It means the water is making up its mind to freeze.
Time-lapse images, Peter Wiley (V7 2003), words, Stephen Murray-Smith (1988), cited in Hince (2001).
grease ice noun
[Grease ice is recorded earlier in northern English with the same meaning, but even the earliest use there is relatively recent (DCanE, 1958).]
The second stage of new sea ice formation (the first being frazil), when small plates of ice begin to clump together, giving the sea's surface an oily appearance, and having a similar dampening effect on waves to that of oil.
1988 Murray-Smith, Stephen, Sitting on penguins: people and politics in Australian Antarctica Hutchinson Australia, Sydney: 62.
That's grease ice. It looks like oil on the water. It means the water is making up its mind to freeze.
1997 Gurney, Alan Below the convergence: voyages toward Antarctica 1699-1839 W.W. Norton & Co, NY/London: 58.
The stages of newly formed sea ice make a chanted refrain that would appeal to the ears of a child: frazil, grease, slush, shuga, pancake.
The Antarctic Dictionary, Hince, 2000; 152
NOTES
Scientist Peter Wiley led the technical support operations for the Australian Antarctic Division (AAD) Marine Science programme on voyage 7 (V7) in 2003. Using a small webcam, he recorded much of the journey around the Amery Ice shelf, where the main scientific program of that voyage was undertaken.
L.R. September 2006
Wiley, P. Grease ice, 2003, still from timelapse digital footage taken during voyage 7 with the AAD, 2003.