the lake I live on was wide open Sunday when my son was out bird hunting. Woke up Monday morning to it being completely locked up. Guys were fishing it starting on Thursday. That happened fast.WAS Duck hunting Sat-Sun on my lake(Hillsdale) and was wide open, no skim..had to go back and get something I left yesterday and she was froze over. Broke through some and holy crap was 2=1/2 in thick! That was quick.