Drivers of 2024 Record Low Sea Ice in Eastern Hudson Bay: A Satellite Era Perspective

Abstract By late May 2024, Hudson Bay (HB) reached record‐low sea ice extent (SIE) and sea ice concentration (SIC), which has been attributed to the persistent easterly winds in May 2024. This study further investigates the role of easterly winds as well as broader contributing factors. The analysis demonstrates that a synergistic combination of anomalously high sea surface temperature (SST) during the preceding July‐November, warmer surface air temperature with reduced freezing degree days (FDD) from November‐April and thin April sea ice, and strong easterly surface winds in May led to the low SIC and SIE. This unique combination of large anomalies did not occur in other years during the satellite era since 1979. This study also reveals that previous winter FDD and easterly wind flow in May are the most important factors determining May SIC in the satellite era. Finally, investigation of the December 2024 record‐low SIC shows the importance of May SIC and July‐November sea surface temperature in delaying sea ice formation in December.