While streamflows are coming down, front range rivers are still pretty blown out. Over the past few years, I have beaten runoff by fishing high country streams. Even early season brookies can be fairly voracious under the right conditions. I didn't find those conditions though when I tried this year.
The streams up high were blown out as well and I had to make the best of the swollen main steam of the drainage. Nymphing along the edges of the faster current in the few narrow eddies produced a few fish.
Although I had only limited success, it was nice to bring a few trout to hand and it was enough to justify a celebration beer. I was surprised I was able to catch anything out of the cloudy, muddy water. Flies that worked for me were a black copper john and a prince nymph. Size is probably not all that critical as long as it is big enough for them to see, but I was using size 16's. I will probably let the water come down a bit more before heading out for another day. It was nice to make it happen in tough conditions and enjoy a day on the water.