Great Lakes Ice Charts, Version 1

These charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002 ice season. Most charts are annotated to indicate data sources. The Straits of Mackinac, Green Bay, and Sault Ste. Marie are enlarged as insets; and in some cases, provided as separate charts. From 1973/74 through 1986/87, charts were prepared by the National Weather Service Forecast Office in Ann Arbor, Michigan. Beginning with the 1987/88 season, the National Ice Center (formerly known as the Navy/NOAA Joint Ice Center) in Suitland, Maryland prepared the charts. Charts are available as GIF files.