In the Sea Ice: Part 1

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Every autumn, the cold winds that blow off the Antarctic plateau and out to sea freeze the sea water surrounding the coastline, turning the surface water into a thick layer of ice, called sea ice. Over winter the constant cold temperatures and lack of sun cause this frozen layer of sea ice to expand further north into the Southern Ocean. At the end of winter this sea ice can cover up to 19 million square kilometers of the Southern Ocean. The return of the sun, milder temperatures, and springtime storms break up the ice and allow it to melt away before the return of autumn and the renewal of the sea ice cycle.

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Apparently, this year the sea ice extent has been the largest since recording began in 1979. Having never experienced sea ice before I didn’t know exactly what this meant but there was a definite expectation that the voyage would extend past the initially calculated 12 days, with stories of being stuck in the ice for weeks circulated through conversations at meal times. After a week in the Southern Ocean we were all keen to enter into the sea ice, firstly, to calm the incessant rocking of the ship and secondly, for a change of scenery. The first iceberg was sighted at 5:18am on Monday 21st October and over the next two days the sightings became more frequent until we were also starting to encounter the outer edges of the sea ice. We finally had a few days of nice weather so we could go out on deck and enjoy the view in the sunshine. In this region the ice was broken up into small pieces, which progressively got larger over the coming days.

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Unfortunately, while the ice got thicker, the weather closed in on us again and we awoke one morning surrounded by nothing but white, unable to tell where the ice ended and the sky started. This slowed our progress significantly. The Aurora can break through the ice but it can only do it with any ease up to about 2m thickness. Any thicker than that and the method of breaking it up requires a lot of back and forward action, where the ice is slowly broken up by the weight of the hull of the ship. In very thick ice this can result in it taking hours to progress only a few nautical miles. By the 28th October we reached a wall of very thick ice, allowing us to travel no further south from where we were. We had made very little progress in the previous few days so our Voyage Leader and Captain made the decision to turn around and head further west  and look for an alternative way through.

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