Sorry, but it is my recollectionThank you very much for this story! But I lived in Lewiston, NY for a while and one year -- I think the winter of 67-68 -- which was one of the coldest on record. The river froze below the falls and the ice built up quite a ways (which was very unusual), happens about every 20 years or so, when they have a severely cold winter. Got our picture in the paper for trying to cross into Canada across the ice (a really stupid idea). We also got arrested.
Sorry, but it is my recollection that the falls do not freeze. Perhaps a partial shell in front of the American falls, but not the falls themselves.
Still a great story, and thanks again.