Post Runoff Means Big Bugs
This time of year is my absolute favorite time to be fishing in the West. As water starts to clear and drop some of the year's best hatches of big bugs start and fish basically go crazy for a few weeks.
Look for big hatches of golden stoneflies and match them with yellow and orange stimulators and other hatch matching stonefly patterns. Remember not to overlook nymph fishing with stonefly nymphs before and after the egg laying flights of the stoneflies get going.
On rivers where they are present look for salmonflies. These things are king sized candy bars to trout so strikes can be absolutely vicious. However, beware that fish seem to gorge themselves on salmon flies so if you don't hit the first few days of the hatch it can be a frustrating affair - big bugs all over and no feeding fish. If that seems to be the case hurry several miles upstream to see if you can get ahead of the hatch.
Also look for green drakes on many Western waters. These hatches can be hit or miss but when you hit hang on. A large fat rainbow on the Henry's Fork taught me that lesson well when I was a kid. I had never fished green drakes, just happened to be in West Yellowstone with the fam, and had an amazing day culminating with an epic fight and break-off of a rainbow that was probably almost 5 pounds. Yep, I was hooked. Be sure to fish nymphs, emergers, adult, and cripple green drake patterns at the appropriate stages of the hatch.
Most of all just be sure to get out and enjoy this time of year.