Henry's Fork Report - May 30, 2024
Henry’s Fork Streamflows
Island Park Dam: 743 cfs
Ashton Dam: 1830 cfs
St. Anthony: 2610 cfs
Fall River: 1650 cfs
As we come out of this Memorial Day weekend and the first days of June, to lay eyes on the Henry’s Fork is to gaze upon a trout stream of dreams; water quality is good throughout most of the system, flows are not too high, much of the river’s character can be seen and its features easily identified. Salmonflies have come and gone in some of the lower reaches and are still present in the upper river. The only thing missing out there is a steady stream of little insects and the silhouettes of regular, surface-feeding trout, which is about par for the course in the week following the first long weekend of the trout season. Weather has been a bit unstable and it appears that this rotation of sunny days and cold, cloudy days is going to persist into the beginning of June. More stable weather is in the current forecast after this weekend. The upper river should be relatively stable in flows, with outflow from Island Park Dam being adjusted to match inflow. Barring any major precipitation events, this should be the case. The lower river will still see some fluctuation in flows and clarity depending on runoff this next week. Lots of snow up in the Fall River drainage still!
Box Canyon
At 743 cfs, the Box Canyon is at a fun flow for fishing, with enough water in there to allow for relatively easy passage for drift boats and low enough for anglers to easily identify the holding water. Salmonflies are imminent and should be in the Box Canyon shortly if they’re not crawling out as I write this. Outside of the salmonfly show, nymphing rigs are the standard choice for the Box-bound angler. We like to keep at least 6’ between the strike indicator and the first fly, with a BB shot for weight, anglers can adjust from there depending on conditions. HF Salmonfly, Waterwalkers, Flutterbugs, Sunken Stones, Rubberlegs #4-8, 101 Stone, BH Pheasant Tails #14-18, red Zebra Midges #14-18, tan and olive HP Caddis Pupa #14-16, Gummer’s Carpet Caddis #14-16, BH King Prince #14-16, and your favorite perdigons in #14-18. We like the Olive Hot Spot, Spanish Bullet, Bullet Quill, Frenchie, CDC French Fly, Duracell and the Light Saber for starters. Be prepared to set the hook at the slightest hesitation of the indicator, the Box Canyon residents don’t move too far for food in early June and strikes will be subtle especially when fishing small flies.
Railroad Ranch
Closed until June 15th. For anglers fishing the Ranch-like waters on the upper and lower borders of the State Park, there are a few fish rising to Caddis and March Browns. Anglers dedicated to the pursuit of sight fishing should come prepared with olive and tan caddis in #14-16, March Brown patterns #14, and some Baetis patterns #18-20. Long leaders (10’-12’) and 5X are usually requisite tackle for this program.
Canyon Country
The canyons are in great shape, flows are at a perfect level for fishing these fast waters and having salmonflies around makes it a fun time to float these sections. Dry fly or dry/dropper rigs are the best choices here, but streamers are always worth a try in the white water if your flies aren’t getting noticed. High floating dry flies like Chubby Chernobyls and HF stones are prime choices, while one needn’t veer too far from the Rubberlegs #4-8 for those subsurface eats. If the trout aren’t responding to your stonefly nymph, try a fast-sinking perdigon #14. This is the one time of year that these canyons can get a little busy, so be sure to give everyone some room and spread the pressure out!
Warm River to Ashton
This piece of water consistently puts smiles on anglers’ faces in a lot of different ways throughout the year, sometimes it’s with lots of action on smaller trout and other times it pays its dividends in larger fish. One way or the other, it’s usually a fun day’s float. Salmonflies have been present for the past 5 days and aren’t likely to last too much longer, but Golden Stones shouldn’t be too far behind with the opportunities they present. Nymph rigs with two flies are the usual program down this way, with a rubberlegs usually being one of the two. Dropper options will be best with imitations of mayfly nymphs and caddis pupa. The same flies we recommend for the Box Canyon would be excellent choices here.
Below Ashton Reservoir
For those venturing into the lower river this week, it’s important to remember to keep your dry fly fishing expectations in check. There will be spotty opportunity on the heels of the salmonfly hatch, but things don’t usually get consistent for another week or so. A keen eye on the Fall River’s flows will help you understand when it may be blown out, affecting the Henry’s Fork below that confluence. There’s still lots of snow up there in the upper watershed and it remains to be seen just how it will melt and come through the system, either all at once or on a slow trickle. This week we’ll be looking for the arrival of Golden Stones, an increase in caddis, and some of the first PMD hatches of the year. Dry/dropper rigs and nymphing rigs shouldn’t be left at home just yet, every day down there in the week to come has at least a period of the day, or even the bulk of the day that is better suited for sub-surface fishing in order to be successful. In the subsurface realm, we are using rubberlegs nymphs #4-8, small mayfly nymphs #14-18, Zebra Midges #14-18, and caddis pupa patterns #14-16. Soft hackles and CDC collars are great features on some of the more successful caddis patterns we’ve been using. As ever, when fishing caddis, don’t be in too much of a hurry to recast once a drift nears its end, the lifting motion of the nymph after a long dead drift elicits strikes from actively feeding trout.
Get out there and have fun!
