Ice can cover submarine operations. And submarines armed with missiles operating in the Northern Marginal Sea Ice Zone littorals can threaten much of Canada and the United States. With the decommissioning of the last Sturgeon-class SSNs, how does the U.S. Navy answer the threat?
Shallow estuaries of large rivers are among the world's most difficult geophysical environments, where only relatively small, highly maneuverable, and properly ballasted submarines can survive. Considering their sea ice cover, Northern Marginal Sea Ice Zone (MIZ) littorals present the most challenging environment of all. The Northern MIZ is simply the arctic and subarctic waters that are ice-covered in winter and open in summer. The Subarctic MIZ is the area below the Arctic Circle (66°33'N).
There are many noteworthy marginal ice zones in the Northern Hemisphere, but three strategically important MIZ estuaries are of particular interest to us: the Gulf of St. Lawrence, the Beaufort Sea Shallows, and the Kara Sea.