Thin ice, deep snow and surface flooding in Kotzebue Sound: landfast ice mass balance during two anomalously warm winters and implications for marine mammals and subsistence hunting

• Published in: Journal of Glaciology
• Main Authors: Andrew R. Mahoney, Kate E. Turner, Donna D. W. Hauser, Nathan J. M. Laxague, Jessica M. Lindsay, Alex V. Whiting, Carson R. Witte, John Goodwin, Cyrus Harris, Robert J. Schaeffer, Roswell Schaeffer, Sarah Betcher, Ajit Subramaniam, Christopher J. Zappa
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2021
• Subjects: Ice thickness measurements; sea ice; sea-ice growth and decay; sea-ice modeling; snow/ice surface processes; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; bearded seal; Journal of Glaciology; ringed seal; Sea ice; Alaska
• Online Access: https://doi.org/10.1017/jog.2021.49; https://doaj.org/article/617078ce448f49218badd0bdc70b4013

The inaugural data from the first systematic program of sea-ice observations in Kotzebue Sound, Alaska, in 2018 coincided with the first winter in living memory when the Sound was not choked with ice. The following winter of 2018–19 was even warmer and characterized by even less ice. Here we discuss the mass balance of landfast ice near Kotzebue (Qikiqtaġruk) during these two anomalously warm winters. We use in situ observations and a 1-D thermodynamic model to address three research questions developed in partnership with an Indigenous Advisory Council. In doing so, we improve our understanding of connections between landfast ice mass balance, marine mammals and subsistence hunting. Specifically, we show: (i) ice growth stopped unusually early due to strong vertical ocean heat flux, which also likely contributed to early start to bearded seal hunting; (ii) unusually thin ice contributed to widespread surface flooding. The associated snow ice formation partly offset the reduced ice growth, but the flooding likely had a negative impact on ringed seal habitat; (iii) sea ice near Kotzebue during the winters of 2017–18 and 2018–19 was likely the thinnest since at least 1945, driven by a combination of warm air temperatures and a persistent ocean heat flux.