Here's the recent history of day 59 data for average ice cover in the Great Lakes:
2011: 34.87%
2012: 06.09%
2013: 18.67%
2014: 85.40%
2015: 88.75%.
Ice cover conditions can change rapidly in the Great Lakes as temperatures drop.
2014 began the year with just 20% coverage, surpassing 60% by the first of February as the average air temperature plunged in January. For example, Grand Rapids, Michigan finished January 2014 6.3 degrees below normal on average. Ice coverage peaked above 92% by the end of the first week of March after a much colder February than normal. Again for example Grand Rapids air temperature finished February 2014 9.1 degrees below normal on average.
2015 is repeating this pattern to a significant degree. Beginning the year with just 5.65% ice coverage, the average cover climbed to only 38% by the first of February 2015 as January was not as cold as the previous year. For example, average air temperature in Grand Rapids was only 3.2 degrees below normal vs. 6.3 degrees the year before. Ice cover rocketed up on average in February, however, as the temperature plunged to finish the month 13.5 degrees below normal on average in Grand Rapids vs. 9.1 degrees below normal the previous year. It took just 11 days in February 2015 for average ice cover to surpass 60%, and just 16 days to surpass 80%.
Average ice cover in the Great Lakes may well surpass 92% as average air temperatures have averaged 1.3 degrees colder in the first two months of 2015 than in 2014.
