As anticipated, still waters everywhere are warming up. That means fish are moving to depth to seek cooler water with higher dissolved oxygen concentrations. So concentrate your fishing at depth on all irrigation reservoirs especially those that will soon be drawn down to satisfy irrigation demands.
The famed hatches are ongoing on the Last Chance-Harriman section of the river. PMD,early flav, and green drake life cycle patterns are best with rusty spinner and caddis life cycle patterns also effective In Box Canyon where some golden stone flies remain. Crowds of fly fishers from all corners of the earth are present and so are etiquette varieties. If you intend to fish the Henry’s Fork, crowds on the lower river have thinned considerably above and below Ashton Dam and the hatches ongoing from the upper river are present and will be until the river warms up (from Ashton Dam to Chester). We have no word on the presence of a significant gray drake hatch here. Because of Henry’s Lake water management actions this spring, flow out of the lake has been meager ( about 20 cfs). This results in fewer fish escaping into the stream below. So fishing in the Flat Ranch section will just be OK.
PMDs and green drakes are beginning to appear on the lower river. So fish their life cycle patterns there, the same for PM caddis throughout, and do not overlook presenting nymph patterns through riffles..The appearance of these mayflies is an indication that the big stone fly appearance is “imminent.” With flows being near historic averages throughout the river, this event could be one not to miss,(for now keep on presenting rubber leg patterns as the big nymphs are starting to migrate towards banks). Consider that with a relatively small number of visits currently on the river, it remains a tranquil alternative to the masses fishing the Henry’s Fork. That will change when the big stone flies appear in number. Also consider that flows will eventually increase as irrigation demands intensify.
It looks like smaller fish make up most catches so far. The best action seems to be along the west side. Fish are moving to deeper water a signal that the lake is warming up.
This is the time to fish small streams that are open in the general season fishing. Some that are not open in this area include South Fork tributaries below Palisades Dam,Willow Creek tributaries and the Blackfoot River drainage above the Blackfoot River Reservoir. Consult with IDF&G’s regulations for other closures. Nearly all forest service and BLM roads are open( the Ashton-Flagg Road opens July 1st). Wet flies will likely bring the most successful fishing for a while on most, however our hot and dry weather means many streams will soon be dropping which will signal a switch to presenting more top water patterns. We will offer information on specific waters as this report goes into the future. Currently the Palisades Reservoir and Salt River tributaries, Buffalo River and tributaries, Birch and Robinson Creeks and Warm River are good candidates for visits. Teton River drainage has a run-off component which should begin decreasing.
It seems almost a tradition that the green drake emergence begins this week on the Harriman State Park section of the Henry’s Fork. Just a glance at the encampments along Harrriman East (See picture) tells you that folks are lining up to enjoy this world class event. Some years the green drakes appear in larger numbers than others, so we will just have to see what happens this season. Mid morning is usually the best time to begin on the river, and consider that green drake life cycle patterns are not the only ones that will be effective. For example: try drifting dry stone fly imitations to rising fish. The initial green drake appearance overlaps the end of the stone fly event, and the fish being present 24-7 are conditioned to take these imitations because they get a bigger reward for the effort of a rise. Cloudy and mild days will produce the densest emergences, but it looks like the foreseeable future days will be bright,and warm.
All the irrigation company owned reservoirs in the southeast corner of the state are offering good fishing. But you had best visit one soon because our low snowfall winter and upcoming hot days mean irrigation demands for their water beginning soon.
Now that the big stone fly event is fading into the rear view mirror, every fly fishing action is gearing up for the green rake event. It is ongoing on the lower river, but when Harrriman State Park opens to fishing, emphasis will shift to the upper river. Already campers/fly fishers are setting up quarters from which to fish. So expect the usual crowds along the river.
South Fork, June 12, 2021
Still a good escape from the crowded Henry’s fork. Flow throughout is at historic mean.Dam to Byington seems to offer best fishing.For nymph fishing, move away from banks, stick to drop offs, transitions and slow water. Hang your favorite bead head nymph off such as a Chernobyl type. Try Super-X, rubber leg patterns and streamers.
Green drakes and PMDs are out on the lower river. Add PM caddis, late and early day rusty spinners, a few straggler golden and big stone flies all making top water fishing great. Look for all these coming on the upper river in a matter of days. Also consider with these icon events you will have plenty of company just about anywhere you fish the river.