Snake River
Riffles and eddies are prime targets for surface patterns with midges dominating and BWOs around in a smattering fashion, especially on day with either a drizzle, snow, or snow flurries. The action has been squarely in the afternoon from around 1pm until 5pm.
A variety of nymphs are working in the same water as well as on confluence seams and troughs. You can get into fish as early as 10 am but production picks up just before noon and slows just after 4pm. Egg patterns have been working well in riffles, confluences, and seams as whitefish spawning continues. Mayfly, stonefly, and caddis imitations are working just about everywhere.
Streamers are working best in riffle pools, ledge rock pools, and backwater side channels with slow currents. Small and moderately sized patterns fished on floating lines or short sinking tips in the INT to 3ips range have been most effective. Go slow with you line retrieves and through in hesitations every now and then.
South Fork
Surface action has shift to midges for the most part, but BWOs continue to pop from around noon until after 5pm with the sweet spot being from 1pm until 4pm. Don’t expect it every day, but when it is occurring, it is worth it. Emergers are getting into fish more so than adults. Both are still worth using. Seams, eddy pools, and riffle current margins are prime targets. Flats can produce well with both midges and BWOs from during the mid-afternoon hours between 3pm and 4:30pm.
Midge and BWO nymphs are working in the same water as adult/emerger patterns and during the same time of the day, but we are hitting a time of the season when roe imitations are picking up good number of fish in riffle and seams. This is occurring throughout the day but is best from around 10am until late afternoon.
Streamers are working best in slow currents, particularly in riffle pools, banks, and wide eddies with sufficient depth. Floating lines and INT sink tips are the way to go. Go with moderately sized patterns and slow to moderate line retrieves.