We visited the falls in winter, just after Christmas when it was all but frozen.
The weather was freezing, it was snowing, and very icy to walk anywhere near the falls
Getting photos is a matter of how much you want to risk your safety.
I know I slipped and fell a number of times on the ice just below the snowy surface in pursuit of the perfect photograph. Alas, I don’t think I succeeded.
The mist was generated from both the waterfall and the low cloud. It was impossible not to get wet just watching the falls.
Of course, unlike the braver people, you could not get me into one of the boats that headed towards the falls. I suspect there might be icebergs and wasn’t going to tempt the fate of another Titanic, even on a lesser scale. The water would be freezing.