Extreme Conditions in the Bering Sea (2017–2018): Record‐Breaking Low Sea‐Ice Extent.

The lowest winter‐maximum areal sea‐ice coverage on record (1980–2019) in the Bering Sea occurred in the winter of 2017/2018. Sea ice arrived late due to warm southerly winds in November. More typical northerly winds (albeit warm) in December and January advanced the ice, but strong, warm southerlies in February and March forced the ice to retreat. The cold pool (shelf region with bottom water < 2 °C) was the smallest on record, because of two related mechanisms: (1) lack of direct cooling in winter by melting sea ice and (2) weaker vertical stratification (no ice melt reduced the vertical salinity gradient) allowing surface heating to penetrate into the near bottom water during summer. February 2019 exhibited another outbreak of warm southerly winds forcing ice to retreat. The number of >31‐day outbreaks of southerly winds in winter has increased since 2016. Key Points: Wind patterns have changed in the Bering Sea, with a marked increase in warm southerly winds since 2016These changes in winds have resulted in decrease in sea ice, with the lowest extent ever observed in the Bering Sea occurring in 2017/2018The low ice extent restructured the horizontal temperature patterns, resulting in an almost nonexistent cold pool in August 2018 [ABSTRACT FROM AUTHOR]