....................... ......Fly Fishing Yellowstone National Park
Fly Fishing Yellowstone - Advice for Current Conditions
The best place to be in Yellowstone Country right now is on the Henry's Fork of the Snake River. The Madison is still high and off color. The South Fork of the Henry's Fork is fishable, but it would be nymphs and streamer fishing, not exactly what most of you would want to travel to Yellowstone for. Of course the Harriman Ranch section doesn't open until June 15th. What I am recommending is below Harriman Ranch. The Firehole River in the park is okay, but not great.
The Box Canyon has been and still is fishing well although it may be high. The section from Riverside all the way to Ashton is fishing well. Below Ashton Dam the river has been fishing well although high. Salmonflies are in full swing everywhere below Riverside. This is where I would be if I were there but I prefer to wait until the middle of June to travel to Yellowstone this year.
For this section of the Henry's Fork, I would use the size 4 Salmonfly Nymphs and Adults (Dry Fly Egg Layers). The real ones are closer to a hook size 4 in this area than they are a size 6.
I would also recommend a drift boat. I don't really like having to do that but you are far better off drifting a large section of the river when the stonefly hatch is underway than you are bank fishing or wading. The hatch moves around a lot. The fish tend to gorge themselves on the nymphs and not feed on the egg layers the first couple of days. Being in the exact right area each day is very important and you cannot do that easily without a drift boat. I'm certain a lot of the guides are busy and booked but you should still be able to find an opening if you don't have your own boat.