I know that was one of the biggest concerns to everyone with the middle of the lake thawing. If you have an offshore wind and a pressure crack, it can move out to the lake and you might not even know that its moving until you get ready to go in and see that the crack separated 20'. Scary stuff!
I think this year was one of the first years that our entire lake froze over completely. We had almost 2' of ice at one point and at that time, i had a dull auger.
The ice was so thick and the cold was so bad that most of the fish that usually make it through the winter, died off. The last time i went out, there were Shad popping up in every hole that was not frozen over and the water stunk. The DNR have already reported that its going to be an EXTREMELY smelly spring due to the dead fish everywhere. They checked for disease and viruses but the only thing that killed them was the abnormal conditions.