Cooler, longer nights are beginning to awake late season fishing here. Cooling waters are starting to move fish away from depths to the shallows where they will forage on available food forms.
There is an extensive selection of effective flies ( once again, see Bill Schiess’s book ” Fishing Henry’s Lake” ) for successful fishing on the lake, but they are too numerous to present here. As fishing improves on the lake, however, we will receive information on effective patterns and will certainly identify such in order to help offer choices.
Flows are beginning to drop enough to make the river a walk-in wade paradise (about 7300 cfs at Irwin, 7500 cfs at Heise, 3200 cfs at Lorenzo). Hopper-dropper combinations still work well along areas of overhead cover and vegetated banks up and down river. The the fall emergence of BWOs and mahogany duns is on the way and will peak during unsettled weather. Fall colors are also beginning, and their presence will make the river and its surroundings a beautiful place to visit.
This year’s One Fly Event is scheduled to take place September 7th-10th. This more that just a fly fishing contest, it is a major fund raising action for protecting the Snake River salmonid population. Go to the Jackson Hole One Fly Contest web site to see details and purpose.
No significant change has happened with respect to flow out of Palisades Dam, and the reservoir above is about two-thirds full. That means plenty of water to finish irrigation season demands as well as a good start in storing water for next year. The recent unsettled weather will help bring on a denser BWO hatch and begin a significant appearance of mahogany duns. Hopper-dropper combinations will be a great alternative for top water fishing in the weeks to come and streamer patterns will become increasingly effective as we move into autumn..
Now that cooling weather has arrived and fly fisher populations are dropping, some the best fishing days anywhere on the river are arriving. True, the autumn mayfly activity peak is not as great as that of late spring-early summer, but terrestrial insects will thrive along the river to feed trout until a killing frost. Streamer patterns will become most effective in interesting trout in the entire river, but as autumn marches on, brown trout in the lower river will become increasingly interested as they begin migrations to spawning areas.
Headlines from Dr. Rob Van Kirk’s Henry’s Fork Drainage Water Status Report of September 2nd
The month of August was slightly cooler than average but 2nd wettest in the 1989-2023 record, with 215% of average precipitation for the month.
Natural flow continued to decrease yesterday, while diversion increased again, dropping lower Henry’s Fork stream flow right to the irrigation-season target.
At an average outflow of 507 cfs, Island Park Reservoir dropped by 109 ac-ft and is 62.6% full, compared with 49.4% full on average.
Our Island Park Reservoir sampling yesterday confirmed well-mixed, turbid conditions on the West End, but so far that turbid water has not traveled to the dam. I still expect the possibility of increased turbidity this weekend, depending on whether all outflow is transferred to the power plant.
September is perhaps the best month to visit the park for fly fishing and tranquility as well as enjoying scenery. Fall River Basin is one of the best location for doing so. Bechler River Soldier Station is where to begin a visit. A walk of a bit more that three miles from the station gets one into Bechler Meadows the home of a river that holds a trout population undisturbed by human development. Hosted here are cut-bow hybrids with a few Yellowstone cutthroats. No rough fish or other salmonids are present! With a huge population of terrestrial insects, it is obvious what to use for top water fishing. Streamer patterns of choice are also effective when presented into holding water. The trout population inhabits the river upstream into the timbered reach with Colonade Falls being its limit. It is a seven mile walk to this unusual waterfall, but it is worth the effort from the fishing and sight seeing standpoints.
The river along the way offers an unheard of number of points to stop and offer a hopper or ant pattern. For sure, getting to Colonade Falls and back makes for a long day, but the experience of doing so will not easily leave your memory.
With a stormy weekend in the works, consider that certain streams will be discolored. For example, northeast corner streams in the Park can color up quickly after storms. It’s a long trip to fish such as the Lamar River and Slough and Soda Butte Creeks. If you intend to try these, consider contacting one of the West Yellowstone fly shops for information on each.
Look for the Firehole River to begin returning to water temperatures that favor trout comfort and activity. Anywhere you fish in the Park (and elsewhere), try not to play fish to exhaustion and release them facing into the current. We want as many as possible back in the water for the remainder of the season as well for as upcoming years.
The gulper hatch and subsequent trout activity has been down compared to that in past years, but a few speckled duns are active on Hebgen Reservoir’s Madison Arm. But you have to search a bit to find where. Flying ants are becoming somewhat numerous and spruce moths have declined on the Madison and Gallatin rivers. With a stormy weekend in the works, it will be time to try streamer patterns just about everywhere. Lake trout will soon become active in Elk Lake, so if you venture there have big streamer patterns and a fast sinking line. In Centennial Valley creeks, cutthroat trout and grayling will begin moving back into the Red Rock Lakes as fall begins it approach.
It’s still flowing too high for good wading conditions below the Dam ( currently about 550 cfs). When and if it drops to around 300 cfs, it will be worth a visit. It can be a beautiful place to fish during the fall season with great scenery, abundant BWOs, caddis and a good residual hopper and ant population. We will keep track of its flow situation and report when to consider a visit.
Up to this weekend hopper patterns with and without a dropper pretty much ruled the effective game. With a stormy weekend being in the forecast, streamer patterns could take over because of relatively dormant hoppers and such unless we have some wind. Flow is not an issue as it remains within the summertime range (currently 8500 cfs at Irwin, 8700 cfs at Heise and 3800 cfs at Lorenzo).
