Most of the rivers in the Great Falls area are in Flood stage. This is a photo of the lower "Great Falls". For scale you can see a huge boom crane at the top of the photo.
This is the Great Falls, due to so much water , it does not appear to even be a "Fall".
Throughout the City of Great Falls you can see whole large trees floating in the river.
Despite all the rivers in flood stage, below Holter Dam 40 miles to the south of Great Falls , the Trout and Walleye fishing remain of good quality. The river at Holter Dam today is 13, 500 cfps, this is high , but still very fishable. There is even some dry fly fishing to be experienced limited as it may be until the water temps get to a higher level, and become stable.This should start in a couple of weeks, at this time we will start to see PMD's, Caddis , and the start of the Trico's.
State wide the rivers are going through "run-off", this is one of those special years where the rivers are cleaned by the scouring of all the water charging down stream. This is needed to take out mud and sand that deposit on the bottom of the rivers which inhibit the growth of aquatic insects. In addition , the flooding water erodes many worms of all kinds ( aquatic and terrestrial ) into a free floating stage that makes easy pickings for the fish to gorge and grow quite fast in a short time frame.
Bottom line, yes we have pretty good quality fishing despite all the flooding your reading about , and seeing on the news. The Missouri River is a very special river environment, that resist droughts or flooding, it is one of the most consistent rivers for Trout fishing found anywhere on the planet.
If you have not fished the Missouri, come out and see what all the fuss is about, big, hard fighting, rainbow and brown trout, very fun!