Sightseers look at icicles at the mouth of a sea cave at the Apostle Islands National Lakeshore on Lake Superior near Cornucopia, Wis., on Feb. 14. The National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory reports that about 94 percent of the lake is covered with ice, enabling thousands of people to visit the islands on foot for the first time since 2009. Overall, the Great Lakes are 88 percent covered with ice. For more photos of the big chill, go to