at almost exactly the same time on the same day, I was drving the amphibious-self-propelled-ice-shack on Big Eau Pleine (just 50 miles straight south of the lake these guys were on)
There is NO WAY any NON-AMPHIBIOUS vehicle should be out there.
there was a foot of ice out in the middle of Eau Pleine, but there was 70 to 80 yds of open water between shore and the ice sheet
we could travel on the ice sheet if we kept moving
but it was so rotten that if we stopped, then the chunk of ice we were on would separate from the rest of the sheet and start to sink under our weight