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During austral spring 2016 Antarctic sea ice extent (SIE) decreased at a record rate of 75 × 103km2d−1, which was 46% faster than the mean rate and 18% faster than in any previous spring season during the satellite era. The decrease of sea ice area was also exceptional and 28% greater than the mean. Anomalous negative retreat occurred in all sectors of the Antarctic but was greatest in the Weddell and Ross Seas. Record negative SIE anomalies for the day of year were recorded from 3 November 2016 to 9 April 2017. Rapid ice retreat in the Weddell Sea took place in strong northerly flow after an early maximum ice extent in late August. Rapid ice retreat occurred in November in the Ross Sea when surface pressure was at a record high level, with the Southern Annular Mode at its most negative for that month since 1968. During austral spring 2016 total Antarctic sea ice extent decreased at a record rate that was 18% faster than previously observedThe most anomalous sea ice retreat took place during November and in the Weddell and Ross Sea sectorsRecord surface pressure anomalies occurred during spring, with the most negative November Southern Annular Mode index since 1968

We assess the impact of El Niño‐induced wind changes on seasonal West Antarctic sea ice concentrations using reanalysis data and sea ice observations. A novel ice budget analysis reveals that in autumn a previously identified east‐west dipole of sea ice concentration anomalies is formed by dynamic and thermodynamic processes in response to El Niño‐generated circulation changes. The dipole features decreased (increased) concentration in the Ross Sea (Amundsen and Bellingshausen Seas). Thermodynamic processes and feedback make a substantial contribution to ice anomalies in all seasons. The eastward propagation of this anomaly is partly driven by mean sea ice drift rather than anomalous winds. Our results demonstrate that linkages between sea ice anomalies and atmospheric variability are highly nonlocal in space and time. Therefore, we assert that caution should be applied when interpreting the results of studies that attribute sea ice changes without accounting for such temporally and spatially remote linkages. A novel sea ice budget analysis is used to assess the causes of a West Antarctic sea ice anomaly dipole during El Niño eventsA dipole forms in autumn due to anomalous winds. Its subsequent progression is controlled by thermodynamic feedback and mean sea ice driftThis demonstrates for the first time that linkages between sea ice anomalies and atmospheric variability are nonlocal in space and time