Hudson Bay freeze-up moving faster than recent years, WHB polar bear habitat imminent

There may not be ice for Western Hudson Bay polar bears to walk on yet but there is still more ice forming along the northwest shore of the bay than last year at this time or even the year before. The Canadian Ice Service (CIS) map for 5 November shows this early formation.

Canadian Arctic Nov 5 2015_CIS

What’s present is mostly grey ice defined by CIS as:

“Young ice 10-15 cm thick, less elastic than nilas [a kind of new ice] and breaks on swell. It usually rafts under pressure.”

Polar bears generally need ice about 30 cm thick to support their weight, which could take a day or two – or a week or two, depending on the weather in northwestern Hudson Bay. For Churchill, along the central coast of western Hudson Bay, ice thick enough for walking will not likely be far behind, given the long-range forecast of freezing weather. In recent years, most Churchill polar bears have left the ice by around 20 November. More maps and graphs for this week below.

CIS stage of development map for northern Hudson Bay for 4 November 2015, showing grey and new ice development north of Churchill:

Hudson Bay North stage of development_Nov 4 2015

Last year’s map at 5 November:

Sea ice extent Canada 2014 Nov 5 CIS

Map for 4 November 2013 (the only one I have on hand):

Sea ice extent Canada_2013 Nov 4_CIS

Map for 12 November 2012 (the only one I have on hand) shows what the next few days may bring this year in Western Hudson Bay if winds don’t blow the ice out into the bay:

Sea ice extent Canada CIS_Nov 12 2012

Photos of Churchill polar bears waiting for the ice, taken during a helicopter tour here.

Below are comparative sea ice graphs for the week of 5 November for various Canadian regions with polar bear populations, showing freeze-up well ahead of previous years.

Hudson Bay, 1971-2015:

Hudson Bay same week Nov 5 Oct 1971-2015 b

Davis Strait, 1968-2015:

Davis Strait same week 5 Nov 1971-2015 a

Foxe Basin, 1968-2015:

Foxe Basin same week 5 Nov 1968_2015_CIS b

Beaufort Sea, 1968-2015:

Beaufort Sea same week 5 Nov 1968_2015_CIS a

The global ice map from NSIDC Masie for 4 November 2015 does not yet show this new ice formation in Hudson Bay but shows Foxe Basin almost filled with ice, with 9.3 mkm2 of ice worldwide at what is not yet mid-fall in the Arctic. Chukchi Sea ice is still far north of Wrangel Island (more on that later) and Barents Sea ice has not reached the Svalbard Archipelago:

masie_all_zoom_4km

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