The main falls don’t look frozen over like that one time that is documented in the museum there.
If you have kids....try this ...it's GREAT FUN! Just don't get burned. Think, more than you have to.
Throw it in front of you, rather than *over head*. Duh.
Step 2.... explain the science to your kids. Really. A wonderful teachable moment.
The Great Lakes don’t normally freeze over completely and neither do the falls. For that to happen you would need sustained arctic conditions and generally temps go up and down enough to prevent that.