Record Early Sea Ice Loss in Southeastern Hudson Bay in Spring 2024

Abstract Hudson Bay seasonal sea‐ice cover plays an important role in marine ecosystems and human activities. Spring 2024 witnessed a uniquely early southeastern opening, leading to basin‐wide sea ice extent falling 5 below the 1979–2023 average. Here, we show that a strong pressure gradient between high pressure over the Canadian Archipelago and low pressure to the south led to unusually strong and persistent winds from the east during May 2024. Consequently, the median sea ice opening date in the southeast was 31 days earlier than the 1979–2023 median, while sea ice opening in the west was delayed by 13 days. Early opening and warmer than average sea surface temperatures have extended the ice‐free period to 202 days in southeastern Hudson Bay, with potentially dramatic consequences on the local marine ecosystem and contributed to the record low Arctic‐wide sea ice extent by December 2024.