During the past month, a massive piece of ice has broken off west of Banks Island, in the Canadian Arctic. This picture shows the area in question, while this animation from the US National Oceanic and Atmospheric Administration.
The split left open water in the Bering Strait for 45 days. At the same time as the fissure, there was an unusual 45 day period of open water in the Bering Strait.
For a sense of scale, here is a map showing Banks Island in relation to the rest of Canada. While one event of this kind cannot be understood without comparison to what is happening in other areas and what has happened at other times, it is a reminder of the dynamic character of the polar icecap, even in the middle of winter. According to NOAA’s 2007 Arctic Report Card, anomolously high temperatures are yielding “relatively younger, thinner ice cover” which is “intrinsically more susceptible to the effects of atmospheric and oceanic forcing.”
It will be fascinating to see what happens the the icecap next summer: specifically, how the level of ice cover will compare to the shocking minimum in the summer of 2007.
[Correction: 15 January 2008] The open water in the Bering Sea is unrelated to this fissure, though both took place at the same time. Both pieces of information are listed in this report from the Canadian Ice Service.