That sure sucked for him.
The problem I have with travel on that lake is that nothing is static. Springs can pop up anywhere at any time. Three years ago there were two such springs flagged that were not there the year before nor the year following. The high water events out ther change the lakebed evry time we see high water. Then consider the temps we’ve had and the fact that those temps not only raise the water temp from run-off but also increase the flow rate.
I feel safer on the Mississippi River than I do on Lake Zumbro. Too bad the guy went in, but then too if he’s been on and around the lake for so many years he should not have taken the ice for granted.