As with the South Fork dry fly fishing concentrates around BWO and midge life cycle patterns. Streamer patterns produce best results for wet fly fishing, although bead heads of your favorite small nymphs will produce. Flows above Ashton Dam remain lower that normal to aid in the Ashton Dam project. Flows below the dam are also low. Low flows concentrate fish into deeper water for overhead cover, so watch heads and tails of holes and runs as well as riffles for rising fish.
As with the South Fork and main stem Snake River flows are down, so wading is a great way to approach the river. Best streamer fishing on the upper river is in Box Canyon where big bows are moving in for the winter. On the lower river browns are moving throughout. Low water means they will be concentrated during daytime, but migrating during low light conditions. Next week with a change in the weather for the worse coming will be a great time to encounter them. The change will also mean good BWO activity. So take your pick for next week: BWO life cycle patterns or streamers!
The lower river features BWOs & midges for top water fishing and streamer fishing for migrating browns and big ‘bows. This cloudy cool weather is just the ticket for both these, and with low flows the river is very approachable to walk-in wading. Box Canyon has the best streamer and nymph fishing on the upper river. The river at Last Chance has a great BWO hatch. Watch the roads, especially early mornings, when you travel through Island Park. Yesterday AM they were very slick just above Ashton Hill and again between Elk Creek and Mack’s Inn.
Above Ashton Reservoir expect lower flows than normal for the rest of the year to help during the Ashton Dam repair project. It appears that the repair project is being conducted in a manner as friendly as possible to the river. Below Ashton Dam flows are closer to normal, browns are migrating to spawning areas, and BWO emergences are in full swing. That makes for some good dry fly fishing and daytime streamer fishing. Try being on the river early & late in the day during cloudy conditions for best results, especially when streamer fishing.
Blue Wing Olives and Midges are bringing fish to the surface. The Lower river and the Box Canyon are fishing well. Nymphing and streamers have also been producing fish. Flows were bumped below Ashton the other day but the water has calmed down now and fishing is back to normal.
Two best places to fish the upper river are at Box Canyon where bead head nymphs and late day streamers bring the best action. Next is Last Chance which offers some very good BWO fishing on cloudy days. The lower river also offers BWOs and nymph fishing with caddis emerging and a few hoppers remaining. But for big fish the best strategy here is to pitch streamers under low light conditions. Browns are moving throughout the lower river, and they are taking steamers. Have dark colored and light colored patterns in your fly box. If one does not produce after a dozen or so casts, switch to the other. Best locations to encounter big browns seems to be below Ashton Dam to Chester backwaters, around the Wendell bridge just north of Ashton, and just below St. Anthony on downstream.
No killing frosts yet, even on the upper river. So terrestrial insects remain plentiful. The Riverside-Hatchery Ford area is a great place to try your skill with terrestrial insect patterns. Flows along the river are below normal. With respect to mayflies, tricos still emerge during mornings on the upper river. BWOs emerge almost everywhere on the river, but overcast or stormy days would bring them on in bigger numbers. Some mahogany duns are hatching. Nymph fishing remains effective in Box Canyon, but look for more responses to streamers everywhere along the river as we advance through October.
Cooling weather is proving to be just what we need. BWOs, caddisflies and some mahogany duns are providing action on the lower river with evening streamer fishing picking up. Look for streamer fishing to improve as we advance into fall. On the upper river, terrestrial insects still provide action, with a hopper trailed by a cinnamon ant (#14) being a great way to encounter big trout. Tricos, tiny BWOs (pseudos), and a few mahogany duns make up the mayfly component this time of year. Small bead head nymphs continue to provide good fishing in the Box Canyon.
As with other waters cooling weather will improve fishing on the lower river. Look for great BWO hatches and some mahogany duns emerging. Evening caddisfly activity will continue. This means life cycle patterns for these insects will be increasingly effective. Terrestrial insects will be available until we have killing frosts. So do not put those chernobyl, hopper, ant, and beetle patterns away for weeks to come. Browns will begin migrating towards spawning areas, meaning streamer fishing will pick up. So the lower river will offer good fishing for many preferences.
Terrestrial patterns provide the best afternoon action on the upper river. We have reports that cinnamon ant patterns are producing very well. Tricos bring action during earlier hours. Cooling weather helps action, especially on the lower river where action has been slower. On the lower river pseudo and trico hatches bring action, but as this month goes on, evening streamer fishing will be improving as browns move toward spawning areas.