Following up on my previous post, it appears sea ice conditions on Hudson Bay this year might be headed for a late breakup due to the dominance of thick first year ice. That would mean a relatively longer on-ice season for polar bears in Western and Southern Hudson Bay.
As of the 1st week in May 2018, most of Hudson Bay, Foxe Basin and Hudson Strait were covered with thick 1st year ice (dark green, >1.2 m thick):
Compare that to the 1st week of May 2016, which had much less thick first year ice than 2018 and more medium first year ice (70-120cm, bright green):
To update the situation, at the end of May this year (week of 28 May), thick first year ice covered even more of the bay with a large patch of open water in the NW corner:
Thick first year ice does not melt as quickly as medium or thin first year ice (lime green) under most conditions, so the amount of thick first year ice present in May strongly affects the rate of breakup of the ice over the summer (temperature and wind also contribute). Here are some charts of ice melt sequences from the past (2016 and a couple others) that give a hint at what might be in store for Hudson Bay polar bears this year.