Henry's Fork Report - August 28, 2025

Henry’s Fork Streamflows

Island Park Dam:  649 cfs

Ashton Dam:  1520 cfs

St. Anthony:  1450 cfs

Fall River:  428 cfs

Turbidity is present throughout the river on a highly variable basis.  For information regarding turbidity, check the Henry’s Fork Foundation’s River Conditions page.  Click on the “Water Quality” link, then select the monitoring station you’d like to view, selecting “turbidity” at the top of the chart for recent and current conditions.  The Foundation is working diligently to understand the complexities of the current situation, but at its core, this is a difficult water year and with a reservoir at 33%, there’s not much clear water upstream to work with.  Stay tuned for updates on current and future projects addressing this issue, the good folks at the Foundation are working hard to consider and develop long term solutions to this issue.

The Henry’s Fork continues to show signs of improving, albeit rather slowly in some of our favorite reaches.  There is some fun fishing to be found in several sections of the river, others hold weather-dependent potential, and the Ranch section is showing a few more signs of life for the most dedicated anglers.  A couple of rainy days kick off this fishing report cycle, followed by a generally warm but partly cloudy weather pattern over the weekend, may breathe a little extra life into the river.  The extra water in the river from these showers just might help with some of the clarity issues we’ve been dealing with.

Box Canyon

For forays into the Box Canyon, anglers will do well to monitor the Henry’s Fork Foundation’s website and check on turbidity.  Anything over 10 NTUs is a no go for us, but 7 and under yield suitable fishing conditions, especially once below the Buffalo River’s confluence.  Flows are at a decent level for the moment, navigation is still fairly smooth and features are easily read.  At this time of year, weeds are an issue, so be sure to check your flies frequently and keep them clean!  Indicator rigs will be the most productive, but dry/droppers and streamers can produce results as well.  Streamers under an indicator are a popular choice at the moment, and a great option when floating through the canyon.  When water clarity is an issue, larger and darker flies can be a good choice, or those with fluorescents and hot spot accents.  For fly selections, we are liking:  BSA boufaces #10, Copper Zonkers #4-8, Olive Zonkers #4-8.  For nymphs:  PTs, R/L Tactical PTs, Split Case PMDs, red and brown Zebra Midges and Rednecks #14-18, black Zebra Midges #18-20, HP Caddis Pupa and Hare/Copper SH #14-18, Rubberlegs #8-12 and SJWs #12-14. 

Railroad Ranch

August is usually a fairly lean month on the Ranch, with sparse but good opportunities.  This year’s August has definitely been lean and the opportunities sparse to nonexistent.  A slowly improving situation is what we’re seeing and we hope it stays the course, September marks one of our favorite months in this fabled piece of water.  That said, anglers should temper their expectations and make the most of what they’re able to find, it’s not easy out there by any stretch and targets are few and far between.  True to the time of year, weeds are an issue, both drifting in the water column and rooted mats that make for complex currents.  Find a way to deal with weeds that is efficient and accept them as part of the game in late summer and early fall.  In addition to terrestrials and spinners, we are hoping to see the arrival of Mahogany Duns this week, which often get Ranch trout moving a bit more eagerly.  For flies, you’ll want to have an assortment of PMD, Baetis, Trico and Callibaetis spinner patterns #14-22, flying ants like Heames’ and Harrop’s Honey Ant, or the Shimazaki CDC ant will do the trick, a variety of hopper patterns, PMD duns and emergers, as well as some mahogany dun and emerger imitations.

Canyon Country

Fishing in the canyons has been fairly consistent in terms of action, the quality of trout varies day to day.  These sections offer a great day out of the weedy environment of the upper river and are beautiful places to spend a day fishing.  Dry/dropper and streamer rigs will do best while on the run, and indicator nymphing rigs will serve you well if you’re stopping to work the water more thoroughly.  Remember that rafts and solid oarsmanship are a must to venture into these reaches of the Henry’s Fork.

Warm River to Ashton

This is a great time of year in this reach, most days anglers will find good action on small to medium sized fish with indicator or dry/dropper rigs.  Streamers can be put into play for less focus on quantity and more on quality.  Brown trout are moving in the system as we speak, getting more colored and territorial as they start to think about the fall and their eventual run to spawn.  The river down here has enough diversity to warrant several streamer rigs and we encourage you to experiment with not only floating lines but different sink tips as well.  For fly selections, refer to those recommended for the Box Canyon.

Below Ashton Dam

Good flows coupled with cool and cloudy weather can make for some fun fishing in the lower river reaches.  Hot afternoons will slow things down, but look for an improvement on the day to day fishing down here over the next few weeks.  Streamer opportunities are present but limited to early and late in the day or during periods of cloudy weather.  Dry/dropper rigs are a good choice through the midday, with hopper patterns on top and small nymphs below.  We like small Rubberlegs, Cocktail nymphs, Zebra Midges, red Jig Napoleons, Black Daggers, Olive Hot Spots and any baetis nymph variety.

Good luck out there!