The Eisack river is like this in Franzensfeste today. It is roaring down with a stupendous amount of water at incredible speed and with a kind of violent force which is frightening to behold. And to top it off, it is rolling large stones along which crash into each other under water and sound like thunder (at least that is what I am told those deep booms come from). It is an awesome sight and sound. This massive flow of water is headed toward Brixen as it cannot be held by the dam in Franzensfeste (the dam reservoir is already almost overflowing) and it may break over its banks in Brixen and further downriver in Klausen (where people in low-lying areas are already being told to move to higher ground, sandbags are being placed, etc.). If one were to fall into the river anywhere today, one would not survive more than a few seconds and would be smashed against the rocks on the riverbed with bone-breaking force almost instantly. I can hear it loudly even as I sit across the street at my desk.
Here is a video I made of the Eisack by the time it is in Brixen. Watch full screen and with sound on. You will see just how wild the river is by the end and how it is flowing very hard and fast and muddy and sometimes spontaneously bursts skyward in plumes as it goes forth frothing and foaming through Brixen. Keep in mind, the video has been slowed down by a factor of 10 (shot at 250 frames/sec) so it is a bit hard to tell just how fast the water is moving.