DULUTH, Minn. – Because of an arctic air mass that’s settled over the Upper Midwest, the ice coverage on Lake Superior grew over the past week. As of Monday, the National Oceanic and Atmospheric Administration reported, nearly 32% of the lake had ice. That’s a rapid increase from 7% a week earlier. Ice could cover 44% of the lake by the end of this week, the agency said. The lake was experiencing historically low percentages of ice in January.
