January 15, 2013 ice cover
This map shows ice cover on the Great Lakes as of January 15, 2013. Notice only parts of Saginaw Bay and Green Bay show significant ice cover.
The map, known as the Great Lakes Surface Environmental Analysis, is a composite of data taken from NOAA satellites orbiting the earth's poles and radar scans of the lakes by the National Ice Center. The resulting image shows surface water temperature and ice coverage, important data for region scientists, fishermen and boaters.
Lack of ice cover leads to increased water evaporation, a serious concern in light of already-low lake levels.
Ice cover will increase with the much colder air expected for the Great Lakes this week.