Tag Archives: ice charts

W Hudson Bay polar bears won’t have an early breakup year, according to sea ice charts

There is still a huge swath of highly concentrated thick first year ice (>1.2m) over most of Hudson Bay this week (19 June 2017) and even in the NW quadrant (the closest proxy we have for Western Hudson Bay), the weekly graph shows levels are greater than 2016, when WHB bears came off the ice in good condition about mid-July. All of which indicates 2017 won’t be an early sea ice breakup year for WHB polar bears.

Hudson Bay weekly ice stage of development 2017 June 19

There is thick first year ice (>1.2m, dark green) in patches along the west coast in the north and south. Thick first year ice also extends into Hudson Strait and Baffin Bay, with some medium first year ice (0.7-1.2m thick, bright green) along the central and southern coasts of WHB.  Note the red triangles incorporated into the thick ice of Hudson Strait in the chart above: those are icebergs from Greenland and/or Baffin Island glaciers. A similar phenomenon has been noted this year off northern Newfoundland, where very thick glacier ice became mixed with thick first year pack ice and were compacted against the shore by storm winds to create patches of sea ice 5-8 m thick.

Compare the above to what the ice looked like last year at this time (2016 20 June, below). There is more open water in the east this year (where few WHB bears would likely venture anyway) but less open water around Churchill and Wapusk National Park to the south than there was in 2016:

Hudson Bay ice age weekly at 20 June 2016

We won’t know for several more weeks if most WHB bears will come ashore at about the same time as last year (early to mid-July) or whether they will be in as good condition as they were last year (because winter conditions may not have been similar).

But so far, sea ice conditions are not looking as dire as the weekly “departure from normal” chart (below, 19 June 2017) might suggest (all that “less than normal” red and pink, oh no!!):

Hudson Bay weekly departure from normal 2017 June 19 Continue reading

Breakup date average for W. Hudson Bay is July 1 – this year, it’s late again

In the last few days, ice coverage on Western Hudson Bay finally dropped below the 30% level that now defines ‘breakup’ for polar bears: a few bears near Churchill started to come ashore late last week but most will stay on the ice until the end of July. That means breakup this year was unofficially July 8th, a week later than average (July 1) for the third year in a row.
Sea ice extent Canada 2014 July 7 CIS

Don’t’ tell that to the folks at Polar Bears International, though, because they’re busy telling people that the ice-free season for Western Hudson Bay bears is now longer than it was before the 1990s. What they mean is that the overall trend is toward early breakup dates.

But what they don’t admit is that over the last 44 years, breakup was a full two weeks earlier than average for Western Hudson Bay only six times and only three of those early breakups occurred within the last 13 years. See the calculations below and see what you think.

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