The first sea ice formation taking place in open waters in the Arctic and Antarctic oceans is
usually loose crystals in a type of slurry called grease ice. Slush is snow entering water, and
blowing snow on Svalbard quite often ends up in the ocean.
A polynya is a large opening in the sea ice, surrounded by sea ice and land. Above a low-tech grease ice
sampler is used to measure the grease ice thickness in the polynya in Storfjorden
(photo by Ragnheid Skogseth at the University Centre on Svalbard
The grease ice thickness was often around 10 cm, but in places reached over 70 cm thickness.
Grease and slush ice has surprisingly high salinities as described in
the an article published in March 2006 by
Smedsrud and Skogseth.