Whoa...on the way to searching out that satellite photo of the 2003 BlackOut, I stumbled upon this photo from 1911. It is really unbelievable that this could've happened, without this picture I'd bet against it.

This image was sourced from http://0.tqn.com/d/urbanlegends/1/0/j/l/19111.jpg.

I'd love to see more shots of the facing of the cliff underneath those falls when they were frozen...

Cheers!