Late freeze-up for W. Hudson Bay polar bears at odds with ice conditions elsewhere

Sea ice is finally starting to form along the western shore of Hudson Bay, lagging well behind ice formation in the rest of the Arctic. Oddly, however, last year it was just the opposite: some WH bears were able to start hunting as early as 31 October (see photo below) while ice formation lagged behind in the Chukchi and Barents Seas.

Sea ice conditions on Hudson Bay 2021

Newly formed shorefast ice (see below at 24 November 2021) rapidly becomes ridged and buckled enough to hold the weight of a polar bear because of the compressing action of wind, tides, and waves. This means Western and Southern Hudson Bay polar bears should be back to hunting seals within the next few days (unless a south wind blows the wind offshore, which sometimes happens at this early stage):

Global ice extent 2021

There was so little ice on the west shore of Hudson Bay yesterday it is barely visible on the NSIDC global chart yet there was abundant ice in the Chukchi and Bering Seas and east of Svalbard in the Barents Sea:

Global ice extent 2020

Last year was quite a different story: a lot of ice in Hudson Bay but little in the Barents and Chukchi Seas:

Despite the slow start, it’s looking like 2021 will not be as late a freeze-up for Western Hudson Bay polar bears as it was in 2016, which as far as we know had no negative effect on polar bear survival.

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