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Part of island surronded by ocean.
Photo Credit: Peter Rejcek

Water, water everywhere

Ice clears out of large area of McMurdo Sound in January

Penguins swim through the water.
Photo Credit: Peter Rejcek
Adélie penguins "porpoise" through the open water of McMurdo Sound.
Aerial view of island and frozen sea.
Photo Credit: Peter Rejcek
The above panoramic of McMurdo Station shows a small pool of open water forming at Hut Point on Jan. 14, about 11 days before the photo at the top of this page.

It's easy to think of Antarctica as an unyielding, unchanging place, forever in a frozen stasis. But the month of January has shown just how quickly things can evolve. Much of the sea ice that fills McMurdo Sound has blown out into the Ross Sea External U.S. government site, as seen above in the aerial photo taken Jan. 25, 2014. While such extensive open water around Ross Island down to Hut Point Peninsula is not common, it does happen on occasion. Most recently, the sea ice blew out in February 2011 after 12 years of being held fast, mainly due to large icebergs that blocked the mouth of McMurdo Sound. [See previous article — Open water: Break-up of sea ice in McMurdo Sound welcomes wildlife, nears airfield road.]

What is really unusual is the timing. The maximum breakout usually occurs around the end of February or the first week of March, according to a 1963 scientific paper by A.J. Heine. Any open water in front of Cape Armitage, the part of Ross Island that is farthest from the top of the photo above, is frozen over again by late March. Heine wrote that the main factors affecting the breakout of the sea ice are "probably a combination of heavy swell, caused by a storm in the open water of the Ross Sea, followed by a strong wind from the south." This year's breakout also seemed to be stimulated by the work of the U.S. Coast Guard cutter Polar Star External U.S. government site, as it carved up the sea ice in McMurdo Sound to clear the way for fuel and cargo vessels to resupply McMurdo Station External U.S. government site.

The clearing of McMurdo Sound also opens the way for wildlife. Adélie and emperor penguins, Weddell seals, along with minke and killer whales, have been spotted as far south as New Zealand's Scott Base External Non-U.S. government site.

For more about this topic, see Bill Spindler's Sea Change in McMurdo Sound webpage External Non-U.S. government site.