Western Hudson Bay sea ice breakup for polar bears like the 1980s for 3 of the last 5 yrs
Posted on August 13, 2024 | Comments Offon Western Hudson Bay sea ice breakup for polar bears like the 1980s for 3 of the last 5 yrs.
The 1980s and early 1990s are said to have been the “good old days” for sea ice conditions and polar bears in Western Hudson Bay, with all tagged bears usually ashore by mid-to-late August. Then an abrupt step-change in sea ice breakup dates brought polar bears to shore an average of two weeks earlier in the late 1990s. From then until 2019, the only significant outlier to all tagged bears being ashore by about late July was 2009, which was such an unusually cold year that the last bears came ashore about August 20.
That pattern changed in 2020, when the last bears came off the ice as late as they had in 2009, on August 21. Something similar happened in 2022, when the last bears came off a small remnant of ice even later, about August 26. And this year, the bears may be moving ashore even later: there is even more ice remaining off WH and much of it is thick compacted ice that hasn’t melted much over the last few weeks, which means bears have been as late onshore as the 1980s for three out of the last five years.
About 40% of all tagged bears were still offshore at August 8. Below, chart showing position of tagged polar bears at August 8 (11/27 or 41% are still on the ice):
https://polarbearscience.com/2024/08/13/western-hudson-bay-sea-ice-breakup-for-polar-bears-like-the-1980s-for-3-of-the-last-5-yrs/
