Breakup for Western Hudson Bay (WHB) is looking to be later than usual this year, given that the average breakup date since 1991 has been July 1 (using a 30% threshold) – only a few days from now – and the ice in WHB is nowhere near 50% coverage, let alone 30%.
Note that few WHB bears come off the ice around Churchill – most come ashore along the southwest coast of Hudson Bay (almost into SHB) and make their way north over the course of the summer to meet the ice as it reforms in the fall north around Churchill – that’s why it’s called a “migration.”
There’s still a lot of ice left in Hudson Bay, as the Canadian Ice Service map for 29 June 2016 (below) shows:
It seems to me that breakup for WHB this year is looking rather like 2014, which was something like a week later than the average since 1991, but time will tell. See below for comparison to 2009 (a late breakup year), 2015, and 2013 (lots of variability!), as well as a discussion of when bears come ashore in relation to this sea ice breakup benchmark.