Thunder River. Getting dirty from Carbondale downstream due to the Crystal. Good hatches of BWO's and midges, with THICK caddis. Nymphing is where it 's at despite the huge numbers of bugs on the surface. Stones, caddis larva, pupa, baetis. The stain in the water lets you fish a little heavier tippet for sure. Streamers have been working with the flows pushing the smaller sculpins and baitfish around. As the water starts to carry more stain, use nymphs with more flash, or larger stones and caddis. Attractor nymphs like tungsten teasers, lightening bugs, and princes are all fishing well in a wide variety of sizes. I know a guide who fishes nothing but princes on the Roaring Fork, and he kills it all season long. If things really get dirty try larger stones, and san juans with flashy nymphs dropped off the back. Look for flows to continue to surge upward for the next month as run off starts to crank. Clear upstream of the Crystal, smaller mayflies have fished best. Caddis larva, pupa, small stones, and mayflies are banging from Basalt up to Aspen. The dry fly fishing has been best with small mayflies mid day, and midges in the evenings. Should be good for a few more weeks before it really starts to rip.