We’ve moved into mid-summer fishing conditions. The weather has been unusually warm and dry. The demand for irrigation has peaked on the Henry’s Fork raising flows below the Island Park Dam. Flows have also been unusually high on the Madison. Fishing has definitely shut down on the lower Henry’s Fork below Ashton. There are still some good fishing options for the next few weeks.
Upper Henry’s Fork
We’ve had some good reports from anglers fishing the Henry’s Fork from Coffee Pot Rapids downstream to McCrea Bridge. The water in the Island Park Reservoir is dropping rapidly which will likely slow the fishing in this area.
We’re into the hottest part of the summer. The air temperature in Island Park has been close to 90° F over the past week. Warm, dry weather requires more water for irrigation for the crops in the upper valley. The flow through the Box Canyon from the Island Park Dam is over 1500 cfs, about as high as it normally gets. Wading in the Box is difficult but the higher flows provide some great benefits. The high flows also move more trout into the banks. Streamer fishing has been good in the predawn and dusk hours. Use sculpins, zonkers and bugger patterns. Small Beadhead nymphs work best during the day. You’ll need to use a pair of tungsten beads to get the flies down. My favorites are Red or Olive Zebra Nymph, Flashback Pheasant Tail, and Skinny Nelson.
Last Chance / Harriman Park
The best fishing has been during the morning hours. There have been several different spinners on the water as well as some caddis. One of the best spinner patterns to use this time of year is a Hi-Vis Rusty Spinner in size 14 or 16. This pattern imitates the Flav Spinner as well as the male Pale Morning Dun. Female PMDs are lighter – the same color as the dun. I normally clip down the orange post so the fly rides low in the surface film. You’ll also need size 16 Callibaetis Spinners. Later in the day look for Pale Morning Duns. The Flav hatch is winding down but you will still see some of these large mayflies emerging on cloudy afternoons. Terrestrial insects are also coming into play. It is wise to carry a few ant, beetle and hopper patterns.
Wood Road #16 – Pinehaven
This water is similar to the Ranch. Use the same recommended patterns. You can also expect good hatches of Pale Morning Duns in the afternoon hours. These aquatic insects emerge all along the east bank of the river where cool springs enter the river. Trout hold in these areas. They are the most selective trout on earth. You’ll need exact imitation emergers, cripples and duns along with a perfect presentation to fool these fish.
The canyon water from Riverside Campground downstream to the confluence with Warm River essentially gets very little attention during mid-summer. The water is very similar to Box Canyon. Use the same patterns and techniques we recommend for Box Canyon. Now that the flows are high the fishing likely isn’t worth the effort unless your main objective is to get away from everybody. If you want to hike down into the canyon you likely won’t have any company.
Warm River to Ashton
The Warm River to Ashton float has been very productive. Most of the fish will be small but you will almost always hook up with a few trout in the 18” – 20” range in the course of the day. Whitefish are another treat that will keep the action going when fishing with nymphs. There are two good ways to catch trout on this float. Use a high visibility dry fly like a Chubby Chernobyl or Green Machine with a nymph dropper 24” below the dry. The most productive nymphs are Red, Olive and Green Zebra Nymphs, Tungsten P T Flashback, and Tungsten Prince Nymphs.
Ashton Dam to St Anthony
The river below Ashton and St Anthony always takes a hiatus during the middle part of the summer. Some anglers get pretty frustrated with this as there are lots of quality fish in this section. We feel it is beneficial in the long run. The water temperature ramps up, the river becomes choked with aquatic vegetation, the bugs quit coming off and the trout stop rising. In another week or so some of the backwaters will be productive with Tricos.
St Anthony to Confluence
Low water, warm water temperatures, lots of floating vegetation, tough fishing.
Henry’s Fork Tributaries
As always, Warm River and the Buffalo provide great fishing for small trout throughout the heat of the summer. Both streams are spring creeks that remain cool enough to keep trout active. The water flow on the lower Fall River is dangerously low. The flow is good in the Upper Fall River. If you haven’t fished Fall River you’ve missed a treat. It is one of the hidden gems in the Henry’s Fork region. Use tungsten bead nymphs dropped about 2 feet below an attractor dry fly.
The flow on the Madison below Hebgen Lake is back to where it normally should be this time of year. The water temperature is creeping up making afternoon fishing difficult. The USGS reading at the Kirby Ranch as of this writing is 22.2° C which is almost 72° F. Morning and evening fishing has been very productive. Use a dry / dropper with a Stimulator or other attractor as the dry with a red or brown Zebra Nymph as a dropper.
Warm weather has started to concentrate fish near the mouths of some of the springs and creeks. Targhee Creek has seen the most activity. Anglers have also been catching trout near Hope Creek near the cliffs, Staley Springs and in some of the deeper springs like the Blue Roof Hole out in the lake. Best patterns have been scuds, Mitey Mite, and Crystal Buggers.
Fly fishing at Island Park has been spotty but things are starting to pick up on the north side of the lake near Trude Bay and Grizzly Springs. Look for this fishing to improve as the reservoir level drops to meet downstream irrigation demand.
Gulper fishing has been productive on Hebgen Lake. Best action is during calm mornings when large trout cruise the surface feeding on Callibaetis mayflies. It is possible to catch trout from shore on the north side of the lake but in most cases you’ll need a float tube, pontoon boat or boat. Best action is to us a dry fly that is easy to see like a Parachute Adams with a size 16 Sawyer PT Nymph as a dropper about 8 inches below the fly.
South Fork of the Snake
The South Fork has hit its ho-hum time of year. Fishing the banks has been productive with hoppers, golden stones, and Chernobyl Ants. The riffle fishing has been relatively tough. PMDs and other mayflies don’t come off well in hot, dry weather. Things could change with some cloud cover.
Yellowstone National Park
The water temperature is too warm on the Firehole, Madison, and Gibbon Rivers. The trout numbers are thin on the Yellowstone River but the quality is high. There are some real big cutthroats that easily top 20 inches. Other good options in the park are the Lamar River, Slough Creek, and the upper reaches of the Gardiner River. You should also consider a trip to the Cave Falls area on Fall River. This water is loaded with small rainbows that are always eager to take your fly.