Flow has been nearly constant for about a week and water is warming. This means PMD and pink albert hatches will soon be providing the best action especially at the heads and tails of riffles. Hoppers are beginning to be important on banks of the lower river.
Without a doubt, Beula Lake currently offers the fastest fishing in the Park! Only Yellowstone cutthroat occupy the lake. You can enjoy this best by packing a flotation device the 2.5 miles into the lake then fish outside the lily pads and other vegetation. If you cannot pack such a device, hike over to the inlet at the southeast corner and fish out into the lake. Small leech, speckled dun, damsel fly, and cinnamon caddis life cycle patterns will provide action. On all Fall River Basin streams stealth is the word with waters nearing base levels but hopper populations building.
The Yellowstone River from the Lake down to the upper falls offers fishing for a few very large cutthroat. Streamer patterns fished in the deepest water is the best way to encounter these fish.
Northeast corner streams ( Lamar, Slough, Soda Butte) are in great shape with green drakes, PMDs, PM caddis and building terrestrial insects, but easy access places on each are crowded.
If you try the water (it’s a bit high because of downstream irrigation demands) from Last Chance through Harriman State Park the rusty spinner (size 14-20) is the “must have” fly. Afternoon caddis activity offers several types of insects, and hoppers are beginning to show. Fishing on the lower river is slowing down, but crowds have gone over to the South Fork
As water warms, look for increasing mayfly activity. Right now evening caddis activity is very good here, and nymph patterns presented through heads of riffles are working. With flow at the dam around 12300 cfs (13000 cfs at Heise, 5500 cfs at Lorenzo) water is where it should be but needs to warm a bit. Expect crowds at all boat ramps. There are stories of crowding and social situations on the icon water boat ramps and on the stream, seemingly more than in past years. Much of this situation can be understood because many other local outdoor activities such as concerts and outdoor workshops are cancelled except for fishing which tends toward social distancing. Add to this that metropolitan area folks coming here to escape covid-19 situations. So unusual crowding should be expected.
The Yellowstone River below the lake opened to fishing on July 15th, and crowds converged there to try for the large cutthroat. Streams in the northeast corner of the park are coming into good fishing condition, but for those of us in the southwest corner of the Greater Yellowstone area they are a near 200 mile drive and likely crowded on arrival. That makes Fall River Basin streams more attractive with respect to traveling, but you will have to walk further to approach them. Meadow reaches on these streams are drying and flows are bit lower than normal. That means stealth, long casts, and fine tippets are required for success. PMDs are decreasing and sallies are at minimal abundance with a few wind blown golden stones present. Traditional attractor patterns in moderate (#12-16) sizes will be effective. Be bear aware!
Same as the last report: Get to creek mouths and spring holes as early as possible. Use standard Henry’s Lake patterns with a slow retrieve of that intermediate line. If you start having success, expect company to surround you because a common Henry’s Lake practice is using binoculars to observe where fish are responding, then converge on that location to share the action.