Can a winter be so cold that a Great Lake could freeze over?
Maybe when the ICE AGE rolled into the Northern Americas?
Well, the winter of 2014 demonstrated that with the right
ice-cold temperatures, polar vortices, bitter wind, with repeated
assaults(!), that indeed the Great Lakes could freeze over.
Our Great Lake, Lake Ontario, as the deepest, did not.
Take a look at this imagery:
On-line article about 2014 frozen Great Lakes