Though North America is a full month into astronomical spring, the Great Lakes have been
slow to give up on winter. As of April 22, 2014, the Great Lakes were 33.9 percent ice covered.The lake they call Superior dominated the pack.
In the early afternoon on April 20, 2014, the Moderate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Aqua satellite captured this natural-color image of Lake Superior, which straddles the United States–Canada border. At the time Aqua passed over, the lake was 63.5 percent ice covered, according to the NOAA Great Lakes Environmental Research Lab (GLERL). Averaged across Lake Superior, ice was 22.6 centimeters (8.9 inches) thick; it was as much as twice that thickness in some locations.
full report here