W Hudson Bay polar bear season wrap-up: problem bear stats & sea ice vs. 2016

This year, due to an early freeze-up of the sea ice, many polar bears left the Western Hudson Bay area (including Churchill) the week of November 6-12. However, the folks who produce Churchill’s problem polar bear statistics did not generate a report for that week, so we are left with assessing the final freeze-up situation based on the previous report (see it here) and the one they have just released for the week of 13-19 November (below), the 18th week of the season (which began July 10):

Churchill Polar bear alert report Nov 13-19_Nov 20 released

The “quiet” week was almost certainly due to the fact that very few bears were still around, having left the previous week.

While it is apparently true that a south wind briefly blew ice away from the area around the town of Churchill, most bears had left by that point and there was plenty of ice to the north and southeast for bears that had congregated outside the town to wait for the ice to form.

Churchill sits on a point of land (see map below) that makes new ice vulnerable to winds from the south but this year impact was small: the north winds returned within a few days and so did the ice.

Hudson Bay weekly ice stage of development 2017 Nov 20

By this week there were still a few stragglers that hadn’t left shore but most of these were mothers with cubs, as well as young bears living on their own, who often hold back to avoid dangerous encounters with adult males at the ice edge.

A few adult males that were still in excellent condition after 4 months ashore without food seemed in no particular hurry to resume hunting. In part, this may have been due to the rather foul weather prevalent since the first week of November (with howling winds, low temperatures and blowing snow much of the time).

You can see in the chart below just how much more ice there was for the week of 20 November compared to average — all those dark and light blue areas along the west coast of Hudson Bay (and east of Baffin Bay) indicate more ice than usual. Even Southern Hudson Bay has enough shore ice for bears to resume hunting. Foxe Basin (to the north of Hudson Bay) has less ice than usual (red and pink) but there is still enough ice for polar bears there to begin their fall hunting, as the chart above makes very clear.

Hudson Bay weekly departure from normal 2017 Nov 20

Freeze-up and bear movement offshore were about three weeks earlier this year in Western Hudson Bay compared to 2016, which made a huge difference to the number of problem bears in Churchill, see below.

More than twice as many bears were handled in 2016 compared to 2017, and more than twice as many incidents were responded to by the polar bear patrol:

Bear Stats Dec 12 2016

Sea ice the week polar bears were released from Churchill jail in 2016, at week 23 of the season:

Hudson Bay weekly concentration 2016 Dec 12

Compared to the week before:

Hudson Bay weekly concentration 2016 Dec 5

What about 2015?

Bears came ashore about a week earlier (1st week of July) and left a couple of weeks later than this year:

2015 Nov 16_22_at Nov 23

via polarbearscience

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November 23, 2017 at 12:16AM

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