Henry's Fork Report - July 13, 2023

Henry’s Fork Streamflows

Island Park Dam:  1350 cf

Ashton Dam:  2130 cfs

St. Anthony:  1150 cfs

Fall River:  339 cfs

Fishing in the caldera has been good this week, but the hot days of summer are starting to take their toll on the midday hours.  Sunny and cloudless conditions will put the best opportunity in the morning hours until midday, with evenings that can bring things back to life.  Cloudy weather will increase activity on these mid-July days.  Expect some upsets out there with water conditions fluctuating more than we anticipated last week, but anglers that adjust for the conditions and seek quality trout fishing will find it.

Box Canyon

As many rivers in the west are dropping to their mid-summer flows, the upper Henry’s Fork has climbed back up to almost twice its volume from a week ago due to irrigation demand downstream.  Thankfully, water clarity and fishing remain good.  At these flows, the Box makes for a terrific place to spend the whole day or for a several hour float.  Keep your eyes open for golden stonefly activity, there are good numbers in the canyon at the moment and when they fly, the Box’s rainbow trout are on the lookout.   Otherwise, indicator nymph fishing rigs remain the standard choice.  Flavs, PMDs, and caddis are all around, fly selection should reflect this.  We still like PTs 12-16, tactical R/L PT, rubberlegs stonefly nymphs 8-10, zebra midges in red and brown 14-16, Frenchies 14-16, Hare/Copper 14-16, SH Hare’s Ear 14-16 and your favorite perdigons: Olive Hot Spot, Jig Napoleons red and yellow, Bullet Quills, Spanish Bullets 12-18.  Keep an eye out for pleasure floaters, they come through in waves, but a quick stop to let them float by will reward you with more moments of solace than chaos, the Box’s quick flows will have these floatillas disappearing around the next corner in short notice.

Railroad Ranch

With flows changing, expect to see trout spreading around and moving into new feeding lines where bug production is still high.  It’ll be worthwhile to be prepared with a few green and brown drakes, but the focus will be on flavs, caddis and PMDs this week.  The odd golden stone isn’t out of the question, either.  Mornings should be spent looking for spinner falls, PMD emergences will come through the late morning and early afternoon, with Flav emergences and spinner falls in the evenings.  This can start earlier if the weather gets cloudy and/or stormy.  If flows don’t creep up too much further, we could be in good shape for a couple more weeks.  Daily Flav hatches will keep the trout looking up.  Caddis will appear in sparse numbers but are significant and you’ll do best to be prepared with down-wing and spent imitations in 14-18, tan and dark. 

Canyon Country

Mid-summer is a great time of year to slide into the canyons of the Henry’s Fork.  High canyon walls make for longer mornings and evenings with fewer hours of overhead sun.  Higher flows make for smoother passage in some of the more boulder-laden reaches.  There are always some golden stones around in this country during the summer months, so the dry fly portion of the dry/fly rig can still be in effect.  If fishing is slow, take some time to pull over and work some likely lies with a streamer or nymph rig.  Flows are high, making some of the deeper water difficult to access, but food is abundantly available and there is enough water for trout to spread around.  Remember, these sections require solid oarsmanship and usually a rubber raft.  Don’t forget your life jackets and rain gear!

Warm River to Ashton

This beautiful piece of water is still putting smiles on anglers’ faces as a multi species endeavor:  rainbow and brown trout, whitefish, and the occasional sucker are all on the nymph bite and are willing to put a bend in the rod for young anglers and those new to the sport.  The pleasure floater crowd is in full effect down here, so enjoy the mornings and be prepared to see a little variety in the type of watercraft in the afternoon hours…you just might see a unicorn come floating by!  Early starts or evening runs are a good choice for the streamer angler on the hunt for a larger trout, and dry/dropper anglers will do well to stay ahead of the “splash and giggle” crowd as well.  Fly selections should be similar to the Box Canyon less the flavs.

Below Ashton Reservoir

The lower river has been giving some good dry fly opportunity this past week for those who are willing to seek it out.  It’s unusual that we haven’t had water temps hit 70 degrees by the middle of July down there, but it hasn’t happened yet, with highs getting close to the 67.5 degree mark these past couple of days.  Higher air temps on the horizon for the coming week threaten to shut down the remaining bug activity, but a morning or evening spinner fall session will still be worth a shot.  Spinner patterns in rusty, cream, olive in 12-18, polarized sunglasses, a keen eye for spotting riseforms and some fresh 4-5X are about all you need when heading down here.  When water temps hit 70 down there, that’s usually about the end of it for a while.  Good but spotty fishing can be found throughout the lower reaches during these morning sessions.

Good luck out there!