Daily Archives: April 5, 2022

Sea ice average for March is the metric used to compare to previous winters

The average sea ice cover at the end of March is the metric used to compare ‘winter’ ice to previous years or decades, not the single-day date of ‘most’ ice. This year, March ended with 14.6 mkm2 of sea ice, most of which (but not all) is critical polar bear habitat. Ice charts showing this are below.

But note that ice over Hudson Bay, which is an almost-enclosed sea used by thousands of polar bears at this time of year, tends to continue to thicken from March into May: these two charts for 2020 show medium green becoming dark green, indicating ice >1.2 m thick, even as some areas of open water appear.

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