Although some of the stations were operational in the 1950s, virtually all of have been in operation since 1967. During the Great Lakes ice season spanning November to April, observers record the number of days ice is visible on the water and the number of days solid ice covers the entire field of view. Assembling the data into monthly summaries, Balling computed the number of days in the ice season when any ice is visible and the percentage with total ice coverage. The seasonal data were averaged for all 19 stations and show an average of 41 percent of the days with some visible ice and 24 percent with ice covering the entire view. While there is no trend in the percentage of days with total ice coverage, the number of days with some ice coverage has increased from 35 percent in the 1960s to a mean value of over 45 percent within the last decade.
Scientists predict a decrease in Great Lakes ice and the historical record shows an increase.
The captain of the Titanic had a little problem with ice, and his ship sunk.