Freeze-up and Break-up of Arctic Sea Ice in the U.S. Beaufort and Chukchi Seas (2022-2023)

After prior freeze-up studies (2009-10 through 2016-17, then 2019-20 through 2021-22) established long-term warming, delayed freeze-up, and multi-year ice invasion trends in the Alaskan Beaufort and Chukchi Seas, continued monitoring was needed to determine whether the record-warm 2021-22 winter's multi-year ice invasion would extend to a fifth consecutive year and whether the freeze-up delay trend would continue accelerating. This twelfth study in the series, commissioned by BSEE, was designed to document the 2022-23 freeze-up season by describing evolving ice conditions, mapping features and pile-up events, correlating ice canopy changes with meteorological conditions, and using the full multi-year dataset to characterize present-day freeze-up processes relative to the 1980s. Researchers combined meteorological data, ice charts, drift buoy data, and RADARSAT-2, RCM, VIIRS, and MODIS satellite imagery collected from September 2022 through February 2023 with four aerial reconnaissance flights conducted in late February and early March 2023. The season set records for latest freeze-up timing and longest freeze-up duration in the Beaufort (70 days) alongside the highest storm count and storm-day total yet recorded in the Chukchi (22 storms, 50 days); multi-year ice invaded the region south and west of Point Barrow for an unprecedented fifth consecutive year via a Multi-Year Gateway in mid-February; and Katie's Floeberg failed to form for the fourth time in six years. The twelve-year dataset confirms accelerating freeze-up delay (3.2 days/year in the Beaufort, 3.7 days/year in the Chukchi) and updated invasion probabilities—about 25% per season for Beaufort multi-year ice and 70% for Chukchi—while a new ice-loads assessment concludes that reduced invasion frequency and floe thickness have likely lowered design global ice loads on fixed structures since the 1980s, a finding with direct implications for offshore facility design standards. This abstract was drafted with the assistance of Claude, July 2026.

Following previous break-up studies, which found that break-up was trending earlier while freeze-up trends later—lengthening the open-water season—alongside rising storm frequency and a persistent but diminished multi-year ice presence, a fifth season of data was needed to strengthen these conclusions and continue tracking multi-year ice behavior during break-up. This fifth break-up study, commissioned by BSEE, was designed to describe the 2023 break-up season, map ice features and pile-up/ride-up events, correlate ice canopy changes with meteorological conditions, and compare the 2017 and 2020-2023 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 2023 with four aerial reconnaissance flights—two in the Chukchi in mid-June and two in the Beaufort in early July. The 2023 season was the second-warmest on record in the Chukchi (667 accumulated TDD) yet remained storm-quiet in both basins, with only three Chukchi storms and four Beaufort storms recorded; landfast ice deteriorated in stages through May and June before nearly complete loss in the Beaufort by early July; and multi-year ice remained absent from the nearshore Beaufort and reentered the Chukchi only briefly and at low concentration in the study's second half. The five-year dataset reinforces that break-up and the onset of open water are trending earlier while freeze-up trends later, with the rate of change highest for pack ice, moderate for landfast ice, and negligible for lagoon ice; storm frequency during break-up has risen nearly 50% since the early 1980s; river overflood timing remains essentially unchanged in the Chukchi but continues trending earlier in the Beaufort; and while multi-year ice residency during break-up has declined since the 1980s, its presence in three of the past five seasons confirms it remains a relevant consideration for offshore operations. This abstract was drafted with the assistance of Claude, July 2026.