Great Lakes ice extent increased significantly on Saturday. Above is the Saturday Ice Extent Map. Compare that map to the map below, showing the ice extent on Friday:
Surface ice cover on Lake Erie increased from 12.2% to 32.5% and Lake St. Clair increased from 53.3% to 84.4%. Lake Michigan ice extent increased from 11.2% on Friday to 13.4% on Saturdayand the Great Lakes as a whole increased from 8.3% to 12.6%.
This is the historical record of Great Lakes maximum ice cover. The graph starts in 1973, when we started to have good visual record from satellites. We were up as high as this past week. The 15.6% total pushed 2021 down from lowest to fourth lowest extent since 1973. It’ll go lower than 4th place. However, it will jump around as we get periods of warm air and cold air and days when a strong wind will cause ice to break up and days when calm winds will allow more ice to form.