High Arctic sea ice mobility rises marine hazards off Newfoundland

Heavy ice conditions along Canada’s east coast during spring 2017 presented hazardous conditions for the maritime industry at a time of year when vessels typically do not need to contend with sea ice. Greater ice concentrations and a thicker ice pack than are typical of this area created the anomalous ice cover, according to a recent study by the American Geophysical Union.

Namely, the  ice conditions along Canada’s east coast during spring 2017 required the Canadian Coast Guard to pull its research icebreaker, CCGS Amundsen, off its scientific cruise, to provide ice escort services and conduct search and rescue operations along Newfoundland’s northeast coast.

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The study -issued at Geophysical Research Letters and funded by Manitoba Hydro, NSERC, ArcticNet, and the Canada Research Chairs program- presents in situ observations of the ice cover, confirming that pieces of multiyear sea ice from the high Arctic were present within the ice cover, and subsequently examines the transport pathway that connects the export of thick multiyear sea ice from the Lincoln Sea and Canadian Arctic Archipelago to coastal communities in Newfoundland.

In situ observations from aboard the Canadian ice breaker Amundsen confirm that multiyear sea ice from the High Arctic was present and that two storms in late March compressed this thick ice cover onshore, where it persisted into late July. Researchers explain:

Within this work we connect the export of thick multiyear sea ice from the High Arctic and Canadian Arctic Archipelago to downstream areas where this thick multiyear ice cover is advected during winter. As the Arctic ice pack has declined in aerial extent and thickness, it has become increasingly mobile. This has contributed to increased ice transport through narrow channels along the periphery of the Arctic Ocean (i.e., Bering Strait, Nares Strait, and interisland straits of the Canadian Arctic Archipelago) and increased the presence of thick multiyear sea ice from the High Arctic at more southern locations that have typically not contended with such sea ice.

Conclusions

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1. Observations of the geophysical and electromagnetic properties of the ice cover confirmed that MYI was present within the ice cover, while complementary observations from ice charts and other spaceborne sensors reveal that these MYI floes were advected over 3,000 km from the Lincoln Sea and CAA to the coastal waters around Newfoundland within one ice season.
2. Based on tracking the MYI edge, researchers determined that MYI must enter Baffin Bay through Lancaster Sound between early October and mid-January or enter Nares Strait from the Lincoln Sea between September and December in order to be transported to Newfoundland before the ice edge begins to retreat in early May. While it is typical for MYI to be advected southward through Baffin Bay and the Labrador Sea toward the southern ice edge, this ice is typically well offshore and melts out along the southern and eastern ice edges. However, in late March to early April 2017, two cyclones passed south of Newfoundland and drove the MYI floes into coastal areas where the ice cover remained present until it eventually melted out in late June. These storms created an unusually strong SLP gradient across Newfoundland and fostered strong onshore winds at a time of year when MYI was present in the offshore area.
3. Under a changing climate, the Arctic ice pack has become increasingly mobile, with increased ice drift speeds and increased ice export through narrow channels due to the reduced likelihood of ice arch formation.
4. Changes to the ice flux through Nares Strait have implications for areas downstream that have not typically encountered MYI from the High Arctic and may be facing a new form of marine hazard. Thicker sea ice may become more present at southerly latitudes as ice flux increases through straits that have historically been seasonally blocked by ice arches—a counterintuitive outcome of a warming Arctic and diminishing ice cover.