The one constant about any trout stream is that it is always changing. The flow of water will change over the course of time. The runs, riffles & pools that you know & love to fish will not always be there. Sometimes it can take years for this to happen, sometimes it only takes a few seconds. When there are strong storms along a trout stream, you can be almost certain that it will have at least a small effect on the steam itself. This might very well change how we fish a part (or parts) of those streams.
Besides the erosion caused by heavy flooding, one of the biggest impacts from storms that will effect us anglers are downed trees. It's important to note the trees along the streams you like to fish & look at their condition. A section of stream you might have passed over before, devoid of any fish, might become a great spot for trout or bass after a windfall lands in the water.
Take a look at this photo. How much longer do you think that tree is going to remain upright & out of the water? I don't know if you can see it or not, but the water here isn't very deep at all. What will happen to the water there after that tree comes down into the stream?......I think it's going to make a very nice, deep pool there someday that will hold a lot of trout.
That same flood also started to compromise the integrity of the far bank on the right side of the photo. In the next few years, that tree began to lean more & more towards the horizontal. Sooner or later, it's going to end up in the stream, creating another seam for the trout to stack up under......until another powerful flood comes along & pushes it out of the way......& the cycle continues.