A lot of rain brings either amazing conditions or unfishable conditions. The difference is usually a day or two. If you have a river that is rising and is getting muddied up, the conditions will be terrible. However, right after the rains start to lighten up, or stop altogether and the flow goes down, a lot of rivers turn into feeding troughs.
When a river is high and moving fast, the fish move to the banks and hide out in slow moving water, and wait for the storm to pass. When the river goes down something turns on in the fish, especially Browns, and they go nuts for anything looking meaty and swimming by them. Whether you are in a boat or wading, if you have a chance to fish a river that is slightly off-color and receding, you are going to be in streamer heaven. All you have to do is pound the banks, and hit as much water as you can. I learned this summer from the guides I worked with that streamer fishing, at least where we were doing it, is not relaxing. Cast, strip,strip,strip,strip, pick up and cast again. We would probably hit our streamers twice in the water for every 12 inches of water we passed. After about 45 minutes, if you are not sweating (for the fat guys it's about 10 minutes) you aren't doing it right. Sinking line makes the difference because when you are covering as much water as we are, you don't have time to wait for the fly to sink. It has to be down there in a hurry and moving the second it hits the water. If you hit the river at just the right time, it is sure to be a day of casting and blasting you soon won't forget. Jointed hooks are preferable (if the fish are big) and after 20 minutes or so of no follows, switch colors. Zoo Cougars are my favorite, along with sculpin and zonker patterns. White, Yellow, and Black are my favorite colors. Most of the time, if it is in front of their face, a big territorial Brown is going to at least chase it for a while to get your fly out of its area.