Sea ice on the Hudson Bay, a huge body of saltwater in northeastern Canada, displayed some odd patterns during spring and summer 2024.
In early May, exceptionally strong and persistent winds cleared sea ice from the eastern part of the bay, leaving vast areas of open water. Meanwhile, an unusually large band of ice packed into the bay’s western half for much of the summer and lingered there longer than normal.
According to an analysis from the National Snow and Ice Data Center (NSIDC), sea ice on Hudson Bay covered just 205,000 square kilometers (79,000 square miles) in early June, a record low on the satellite record that dates to 1979. The imbalance lasted for several weeks, with the NSIDC continuing to report record-low levels of ice in early July.
The image above (left), from the VIIRS (Visible Infrared Imaging Radiometer Suite) on the NASA-NOAA Suomi NPP satellite, shows Hudson Bay on June 8, 2024, when sea ice was packed into only the western part of the bay. The ice was mostly gone by mid-July, though some patches still lingered when the VIIRS on the NOAA-21 satellite captured the second image (right).
The unusual distribution of sea ice has likely affected the roughly 1,700 polar bears that live around Hudson Bay and rely on its ice. When the bay is topped with ice, polar bears venture onto the frozen surface to hunt for ringed seals and other prey. When the ice melts in the summer, bears retreat to the shore, where they fast or feed on whatever food they can find until the ice returns. Since bears burn about 1 kilogram (2 pounds) per day while on land, too much time on shore can lead to stress, starvation, and conflict with humans.
University of Alberta scientist Andrew Derocher is part of a group of specialists who closely monitor polar bear populations. He uses location information gathered from tagged bears tracked by satellites and daily observations from NASA and NOAA satellites to monitor environmental conditions in Hudson Bay. Though his team does not have tagged bears in the eastern part of the bay, he thinks that the bears there are probably having a “horrible” year due to the early ice breakup.
Meanwhile, the bears on the western side of the bay are getting plenty of time on the ice and may be having what he described as a “great” year. “Winds have kept a band of heavy ice in the west, just offshore, and close enough to swim to land,” Derocher posted to X on July 21. “Sea ice is where the bears want to be. The longer they can stay on the ice, the better.”
NASA Earth Observatory images by Lauren Dauphin, using VIIRS data from NASA EOSDIS LANCE, GIBS/Worldview, Joint Polar Satellite System (JPSS) and the Suomi National Polar-orbiting Partnership. Story by Adam Voiland.
