Well I just got back from Banff/Jasper. It was absolutely beautiful up there if you got away from the insane crowds. Not difficult as most tourists will hike a max of 2 miles
My girlfriend and I fished in a few places. Mostly the Bow river and its tributaries. I did hear mention of the flood when talking to some of the locals. It seems the water and storms blew down a lot of trees and made some of the better areas inaccessible. With regards to the size of fish, I would have to agree with him. Most were small, as in the length of my hand, with a gem or two thrown in. The water was also quite stained which made spotting difficult, but also made it easier to sneak up on target areas. We caught browns, rainbows, brookies, cutthroat, and a few bulls.
Bottom line, I won't be running back there any time soon just to fish. But for the view, Banff is hard to beat
Just make sure to watch your back… You may not be the only one fishing.