Anomalous Floe Dynamics in Nares Strait: A Case Study of Ice Arch Formation

Nares Strait is a narrow channel situated between Ellesmere Island and Greenland, through which the prevailing winds and surface current transport multiyear ice southward from the Arctic Ocean. Seasonal formation of ice arches at the northern or southern terminus of Nares Strait reduces the annual loss of multiyear ice. Since 2007, there have been six atypical ice arch configurations and two seasons in which no ice arches formed. The duration of ice arch days in Nares Strait is trending downward, accelerating multiyear ice loss. Understanding the physical processes of ice arch formation is critical for predicting the future of ice transport in Nares Strait. On 28 and 29 March 2023, satellite imagery showed anomalously limited floe movement throughout Nares Strait. When normal ice flow resumed, a southern ice arch had formed. The data suggests that southerly winds close to neap tide negated the southward movement of ice, causing immobilization of ice in Kane Basin on a scale previously assumed impossible, which led to ice arch formation. The results indicate that winds counteracting southerly ice movement is a mechanism of ice arch formation. This study presents a previously undocumented mechanism of ice formation, one that will increase in importance as Arctic ice thins and becomes more mobile.