Freeze-up and Break-up of Arctic Sea Ice in the U.S. Beaufort and Chukchi Seas (2021-2022)

After prior freeze-up studies (2009-10 through 2016-17, then 2019-20 through 2020-21) established long-term warming, delayed freeze-up, and multi-year ice invasion trends in the Alaskan Beaufort and Chukchi Seas—including an unprecedented third consecutive multi-year ice invasion and newly discovered iceberg features in 2020-21—continued monitoring was needed to determine whether these trends would persist or whether interannual variability would reassert itself. This eleventh study in the series, commissioned by BSEE, was designed to document the 2021-22 freeze-up season by describing evolving ice conditions, mapping features and pile-up events, correlating ice canopy changes with meteorological conditions, and using the expanded multi-year dataset to characterize present-day freeze-up processes relative to the 1980s. Researchers combined meteorological data, ice charts, drift buoy data (including International Arctic Buoy Programme buoys), and RADARSAT-2, Sentinel-1, VIIRS, and MODIS satellite imagery collected from September 2021 through February 2022 with four aerial reconnaissance flights conducted in late February 2022. The season was notably cold and storm-quiet by recent standards, with the highest frequency of westerly winds yet recorded in the Beaufort (70%) and the lowest count of easterly storm-days; multi-year ice nonetheless invaded the nearshore Beaufort for an unprecedented fourth consecutive year; and Katie's Floeberg, a recurring rubble feature on Hanna Shoal, failed to form before the reconnaissance flight. The dataset confirms accelerating freeze-up delay (2.8 days/year in the Beaufort, 4.2 days/year in the Chukchi) and updated invasion probabilities—about 25% per season for Beaufort multi-year ice, 70% for Chukchi, and 20% for icebergs—demonstrating that despite a colder-than-recent winter, the underlying multi-year ice and iceberg hazard trends identified in prior studies continue unabated. This abstract was drafted with the assistance of Claude, July 2026.

Following the previous break-up studies, which found preliminary evidence that break-up was trending earlier while freeze-up trends later—together lengthening the open-water season—along with a rising storm frequency and continued multi-year ice presence, a fourth season of data was needed to strengthen these still-tentative conclusions and extend the historical comparison to the 1953-75 baseline. This fourth break-up study, commissioned by BSEE, was designed to describe the 2022 break-up season, map ice features and pile-up/ride-up events, correlate ice canopy changes with meteorological conditions, and compare the 2017, 2020, 2021, and 2022 seasons with historical break-up patterns. Researchers combined open-source meteorological data, ice charts, drift buoy data, and RADARSAT-2 satellite imagery collected from May through July 2022 with two aerial reconnaissance flights—one in the Chukchi in mid-June and one in the Beaufort in early July. The 2022 season was the calmest yet recorded, with only three storms in each basin versus historical averages near 4.6 and 5.5, respectively, allowing in-situ melting rather than wind-driven displacement to govern Beaufort landfast ice break-up for the first time in the series; multi-year ice nonetheless remained present in both seas for a third consecutive year; and a comparison against a newly incorporated 1953-75 baseline confirmed that Beaufort pack ice break-up and open water now occur roughly three weeks earlier. The four-year dataset reinforces that break-up and the onset of open water are trending earlier while freeze-up trends later, compressing the break-up season itself while substantially lengthening the overall open-water season; storm frequency during break-up has risen more than 40% since the early 1980s; and while a quiet, storm-poor season demonstrates the strength of interannual variability, the historical baseline comparison lends the clearest quantitative support yet to trends the authors had previously flagged as tentative. This abstract was drafted with the assistance of Claude, July 2026.