Swim briefs at NYC New Year Day Coney Island Plunge

[Torchwatch]

A lot of them seem to have the round mouthed cold shock look.
Cold shock paralyses and kills as you go into cold water, if you are underwater you will suck in large amount of cold water and drown.
If you have to go into cold water keep your head up until you have acclimatised and can breathe normally.
A good life jacket or vest will roll you onto your back with you head up, you might cough and splutter but you will survive, be a pussy, wear a life jacket on a small boat or if you intend to swim alone in cold water.