Sitting just south of the Arctic Circle in Canada, the cold waters of Hudson Bay wear a thick coat of ice each winter. Freeze-up beings in October or November and, as days lengthen and temperatures rise in late spring and summer, the icy coating melts. Traditionally ice break-up begins in May or June and Hudson Bay become ice-free by late July or August.
On April 15, 2021, the Moderate Resolution Imaging Spectroradiometer acquired a true-color image of the first signs of spring ice break-up in Hudson Bay.
Warming air temperatures have thinned the ice near the southeastern eastern shore of Hudson Bay and James Bay (the southern extension of Hudson Bay) The warm temperatures, combined with strong winds which push the ice away from the shore, have created several areas of open water and churned the ice into chunks in several places.