The polynya over Maud Rise was visible in a beautiful clear MODIS image on 25 September. It is currently ~40,000 km2 of open water in the middle of the Antarctic winter sea ice. This will be some impressive heat loss.
This is the polynya in the SMMI Data for the same day.
A while back I calculated the heat loss through 2,000 km2 of open water in the Arctic as being ~600 GW. This is about 20 times as much open water…
As I said then, the heat loss is making the surface waters denser, so they sink away from the surface
More to come on this I expect.