Flood waters can be dangerous, but productive if you hit them at the right time. The first order of business when fishing more extreme conditions like this is one of safety. Water is powerful and it deserves your respect...be careful.I recently went trout fishing on a small mountain stream after several days of heavy rain. The stream was up to say the least. It must have been 2 feet higher than normal...which isn't uncommon to see in the NC mountains.
Fortunately the only runoff hitting the steam was through the forest, the water clarity wasn't clear, but it was far from muddy. Dingy would be a good way to describe it, just about perfect! When you hit situations like this you need to slowwww dowwwwn. The fish will tend to move out of the heavy current, many times towards the banks, anywhere it is somewhat calm. I like to use a spinner in these conditions. Black and gold is always a good choice, but I caught fish on a variety of different colors and styles, I do prefer Panther Martin brand spinners though (Size 2 - 1/16 oz, 4 - 1/8 oz, and 6 - 1/4 oz).
The key that I have found to controlling your lure in rapid water like this is to keep your rod tip high and let the flex and backbone of your rod do the work. Cast the lure cross stream to the other bank, overgrowth, log, calm spot, whatever the case may be. Expect an immediate strike or you may miss an opportunity. Then again, you should expect a strike on every cast regardless of the conditions.
Reel in any slack, raise your rod tip, and watch your lure slowly work its way across the stream through the current. The more control you have, the slower you can work the lure...this is key. The longer you hold the lure in the strike zone the better chance you have at some fun. Keep an eye on your lure and watch for any resemblance of a strike. When the lure gets to your side of the stream don't horse it in, reel slowly bringin it up the bank. You never know what may be laying at your feet; I went 11 for 27, mostly small browns and brookies. But I am sure there were many others that I did not see.
All of this fun in about 3 hours of fishing. And the best thing was being out in nature, alone, without any man made noise to speak of in the pouring rain. Embrance the rain and rising waters. These are two of my best friends. God bless and good fishing!!!