Ive been going there my whole life between camps and going back and renting houses with my family. Now my kids are in camp. I think its fair to say anyone thats been going for over a decade has seen multiple flood events, some of which are exactly as you described. Water got THIS HIGH when I was there back in the day, Ive heard that stuff the whole time Ive been there. I can remember at least one summer at camp where it just wouldnt stop raining for days and the water slowly creeped up to the cabins. We just had our stuff on the bunks and the floors in these cabins are typically just concrete slab. Water goes back out, recedes to the river, and you go about your business.
I certainly can see how someone might start to sort of disregard the warnings about flood severity. You hear that stuff but typically it isnt as bad at your place, so you just get in the bad habit of not taking the warnings seriously. Then all of a sudden you're distracted by the 4th of July and and it gets just a little easier to disregard the warnings, and by the time a flood like this starts to head your way, and you actually spring into action, its too late. This thing just moved too fast.