Tag Archives: winds

Polar bear habitat update: open water primarily due to winds pushing pack ice

Posted on May 31, 2019 | Comments Off on Polar bear habitat update: open water primarily due to winds pushing pack ice

Here is a look at what polar bear habitat looks like this year at the end of May compared to previous years. It helps put any predictions of impending doom into perspective.

Polar_bear Bering Sea 2007 USFWS lg

This is the time year when declining sea ice gets some people all worked up. However, declining ice is normal at this time of year and there is always variation in where the most open water appears first. At this time of year, there isn’t much ice ‘melt’ going on. Rather, what we are seeing is the opening up of shore leads and polynyas by winds.

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It’s back: Bering Sea polar bear habitat has recovered from a low earlier this month

Posted on March 18, 2019 | Comments Off on It’s back: Bering Sea polar bear habitat has recovered from a low earlier this month

Fancy that! After a load of handwringing earlier this month, mobile pack ice in the Bering Sea has returned. Just like ice in the Barents Sea, Bering Sea ice is highly variable (Brown et al. 2011): it moves with winds and currents, so a ‘decline’ during the winter usually indicates redistribution, not melting.

Polar_bear Bering Sea 2007 USFWS lg

Polar bear on Bering Sea ice 2007 USFWS

According to researcher Rick Thoman from the University of Alaska Fairbanks, quoted by the Canadian Press:

“Wind blew ice to Russian beaches in the west and to the south side of Norton Sound south of Nome but left open water all the way to Chukchi Sea north of the Bering Strait.”

Polar bears that venture into the Bering Sea are part of the Chukchi Sea subpopulation, which is known to be thriving (Crockford 2019; AC SWG 2018; Regehr et al. 2018; Rode and Regehr 2010; Rode et al. 2013, 2014, 2015, 2018).

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New ice on Hudson Bay a week earlier than 2017: another early freeze-up ahead?

Posted on October 23, 2018 | Comments Off on New ice on Hudson Bay a week earlier than 2017: another early freeze-up ahead?

Last year, an early freeze-up of Western Hudson Bay sea ice almost ruined the Polar Bear Week campaign devised by Polar Bears International to drum up donation dollars and public sympathy for polar bear conservation. Many bears were on the ice hunting by 7-8 November in 2017 before the celebratory week was done (the average date that bears left the ice in the 1980s): sea ice charts suggest the same may be happening this year.

Polar bears off Churchill_2000-11-20_wikipedia

Ice is forming along the Hudson Bay coast more than a week earlier than it was last year (barely discernible on the map below but detailed ice charts show it clearly), consistent with early build-up of ice in the Canadian Archipelago, East Greenland, and Foxe Basin since mid-September.

Sea ice Canada 2018 Oct 23

The question is: will the ice continue to build over the next few weeks or get blown offshore? See the ice charts below for this year and 2017.
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Polynya refresher: open water in spring is due to winds & currents, not ice melt

Posted on May 3, 2018 | Comments Off on Polynya refresher: open water in spring is due to winds & currents, not ice melt

Arctic sea ice begins to open up in spring at predictable locations due to currents and prevailing winds and this was as true in the 1970s as it is today. Polynyas and widening shore leads that most often get mistaken for early sea ice melt are those in the Beaufort and Chukchi Seas and in Hudson Bay.

Beaufort Sea male polar bear USGS_2005 Amstrup photo

But contrary to concerns expressed about possible negative implications of these early patches of open water, these areas have always been critical congregation areas for Arctic seals and are therefore important feeding areas for polar bears.

Seal habitat frozen open lead_Beaufort 2008_Miller

Seals hauled out beside a lightly frozen over lead in Beaufort Sea ice, 2008. USFWS.

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An El Niño year late start to freeze-up on Hudson Bay: bears gearing up to hunt

Posted on December 5, 2016 | Comments Off on An El Niño year late start to freeze-up on Hudson Bay: bears gearing up to hunt

There is no serious ice on the west shore of Hudson Bay yet (as the map below shows) but the winds have just shifted – instead of coming from the south, they are now blowing in from the north.

Freeze-up and a resumption of seal hunting for Western and Southern Hudson Bay polar bears looks imminent. The bears get out on the ice as soon as they are physically able, when the ice is about 3-4 inches thick (about 10 cm).

sea-ice-extent-canada-2016-dec-5_cis

I’m going to let Kelsey Eliasson from PolarBearAlley, on shore at Churchill, convey the gist of the freeze-up situation on the Bay.

Recall that freeze-up was late in both 1998 and 1999 – during the height of that strong El Niño warmth as well as the year following. Continue reading

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