From listening to other expert anglers and fishing for a few years for steelhead....my answer would be dont fish a river thats chocolate brown. you need some sort of visibility to even make it possible to catch a fish without literally hitting them on the nose. So like these guys said...if you ABSOLUTELY have to fish...look for seams/resting spots in shallower water away from the heavy water. also when the craziest places will hold fish. Your other bet is to look for a MAIN tributary (ex. columbia, cowlitz, quillayute, ) and look for creeks that otherwise would be 1' of water that flow into the main trib. since its high water the creeks will be small streams...but usually clearer water. the fish will move up into side tribs to avoid the mess coming downstream. Reasearch, google maps, and leg work will reward you with a gem in the rough. I have a few streams on the columbia that are MONEY on crazy high water. Think like a fish. Look up VHawk on here if hes still on the board. He was fly fishing in the ditch on the Skokomish and hooking ( they were biting, not flossing) silvers and chum. the ditch in the pictures, had clearer water.