Time to consider terrestrial patterns for best chances of success on the upper river. Flavs are well past their peak, and PMDs are smaller and less numerous. Evenings and late afternoons continue to bring activity because of caddis swarms and mornings bring activity from spinner falls. If you enjoy evening action from caddis swarms but want a bit more solitude, try the lower Coffeepot reach. Flow out of Henry’s Lake remains at 100 cfs, so fishing on the river in the Flat Ranch Preserve will hold up until flows drop when water storage begins on the lake. Look for evening caddis swarms, and PMDs emerging during late morning. But again, expect to have best success through presenting terrestrial patterns.
Fishing has been good on the South Fork. All sections seem to be fishing well. The Salmon Fly hatch has now moved through the entire river and fish can still be caught on Salmon Fly patterns from the Dam down through the canyon. Golden stones have been effective when fished tight against the bank. The CFO Flamer Ant, Simulators and chubby Chernobyls have been working well for patterns. Bead head nymph as droppers will pick up those fish weary to rise to dry fly. Run the dropper 18 inches to 3 feet below the dry. No consistency on PMD hatches, but we should start seeing those hatches any day now. Keep checking back as we try to keep this report updated.
Creek mouths with cooler water provide the best fishing now. Trouble is there are almost as many anglers there as fish. We have a report of a four pound brookie being caught and released at the mouth of Targhee Creek. Taking fly was a caddis pupa pattern, and we hear that caddis are quite active with fish responding to them around the lake.
Draw down is impacting fishing on all irrigation reservoirs to the south. We have reports of good fishing on the west end of Island Park Reservoir where blood worm patterns under and indicator are working in many locations. Find the taking depth, and it looks like you will get your chances.
Currently best time for fishing success on many streams here are days when thundershowers threaten. Bright, cloudless days hinder insect activity and also provide reduced cover in the clearer, slower flowing streams. This is particularly true for meadow reaches of such as Slough Creek, Lamar River, Madison River, Gibbon River, and Fall River Basin streams. For best chances of fishing success, observe weather reports for the day you intend to fish. Look for increased chances for cloud cover and showers, and go prepared for these. Where’s the fastest fishing in the Park right now? For still waters my bet is on such as Beula Lake and Riddle Lake. For streams I would suggest Boundary Creek and the timbered reaches of Slough Creek, Bechler River, and Fall River. Get in touch with us for particulars on fishing these.
Conditions on the South Fork this year are those that have made it famed or fishing. Water flows have not only been ideal for float fishing, but also nearly constant. Insect activity has been nearly as expected, and weather, if a bit on the hot & dry side, good. As a result visitations are up, not just through guiding operations but from visiting anglers prefering to go on their own experience. Want to get away from much of the crowds? Begin fishing about 6PM and stay on the water to dusk. Riffle fishing will still be great with caddis taking over and there is the possibility of a spinner fall. Try throwing a streamer when the light is leaving the river. Recently fishing slowed on the lower river because water has been shut down from the Big Feeder meaning increased flows in the river below. Given a few days the river will stabilize and good fishing will return.
The recent thundershowers are just what is needed to extend good fishing on many of these streams. These will be fairly common through summer, and unless a deluge hits directly the cooling effect of a shower on water and rise in relative humidity of the atmosphere above the water are the reasons why right after a shower is a good time to fish. Insects will be more active because the humidity keeps them from drying, overcast sustains it, and with lowered air temperatures they are more able to complete their life cycle. The intensified activity attracts fish to feed. So hang around to see if hatches occur when you see a storm leaving and water levels and clarity seem not greatly impacted.
There are enough flavs and PMDs left to interest fish and make a trip to the upper river worthwhile, but look for terrestrial insects to increase in importance as a food form for fish as we move to mid summer. Want to get away from the crowds at the most popular spots on the upper river? What we know as Henry’s Lake Outlet is really the Henry’s Fork, and as long as a good flow comes out of the lake, good-sized fish will remain there and make it worth the time spent trying for them. The flow out of Henry’s Lake is still over 100 cfs, but is sure to drop as summer progresses meaning the larger fish will eventually move downstream. With the flow at the current level the Flat Ranch part of the Outlet, owned by the Nature Conservancy, is an attractive place to fish. It has a character different from downstream reaches, being a medium-sized meadow stream. It hosts a good mayfly and caddisfly population. Terrestrial insects are important here, and because most of the larger fish originated in the lake, such as damselfly nymph and small leech patterns work very well. Consider trying this part of the river particularly were willows provide overhead cover. Stop at the Conservancy’s Visitor Center just off Highway 20 to check in and observe fishing regulations. Who knows a cutthroat or cut-bow hybrid of the year could be waiting for you.