

You want a Type-1, made to keep an unconscious adult on their back with their head out of the water for an extended period of time. I use type 3 when I canoe on the lake. I’m not a whitewater enthusiast. The type 1 are made for offshore shit where the person might be knocked out when they fall off the boat.
But yeah, in a flash flood it’s only going to keep you on top. Probably get smashed by a tree or a car or something. Best to stay out of floodwater.
edit: but better a type 3 or even a ring than nothing. If I was in a hurricane or flash flood situation I’d rather have a type 1
Maybe OP meant that you fell asleep at the airport and wake up in a panic to an overly loud intercom announcement.
https://www.youtube.com/watch?v=HKGjCPBSG38