National Climate Report - February 2014
Great Lakes Ice
Great Lakes Ice
Historical Great Lakes Ice Cover
March 2, 2014 Great Lakes Ice Cover
During the winter of 2013/14, very cold temperatures covered the Great Lakes and surrounding states. Minnesota, Wisconsin, Michigan, Illinois, and Indiana each had winter temperatures that ranked among the ten coldest on record. The persistent cold caused 91 percent of the Great Lakes to be frozen by early March. This was the second largest ice coverage for the lakes, with data dating to 1973, and the largest on record for the date. The largest ice cover for the Great Lakes occurred late in the winter of 1979, when 95 percent of the Lakes were frozen. Lakes Superior, Huron, and Erie were completely ice covered. Lake Michigan was mostly ice covered, while about half of Lake Ontario was ice covered. Lake Michigan ice cover peaked on March 8th at 93.3 percent, setting a new record for the lake. The previous largest ice cover for Lake Michigan was 93.1 percent, set in 1977. The near-record large ice cover the the Great Lakes is contrary to long-term ice decline for the lakes. Between 1973 and 2010, Great Lakes ice cover was down 71 percent. In 2002, the Great Lakes ice cover was record low at 9.5 percent, and just two years ago the ice covered only 12.9 percent of the lakes. The near-record large ice cover also helped the lakes rebound from record and near-record low water levels that occurred in early 2013. Large ice coverage decreases the amount of water that evaporates from the lakes during winter and spring.