Fly fishing report · West

Henry's Fork

An Ashton-focused Henry's Fork planning page built around the classic ranch and reservoir-to-river corridor, strict section-by-section rules, and flow-aware dry-fly timing.

Check flow & weather

Today's river scoreHigh source confidence

Poor

Best option: Float.

A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.

Updated Jul 13, 11:17 PM UTCUsually refreshes about every 45 minutes

Recommended approachFloat

Mode scores adjust the river-wide score for the risks of wading, bank fishing, or floating.

WadeCheck

This report does not describe this as a primary mode. Verify legal access, depth, launches, and retreat options before planning around it.

Bank / edgeCheck

This report does not describe this as a primary mode. Verify legal access, depth, launches, and retreat options before planning around it.

Float · Best fit35/100

A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.

Confirm before you leave

Flow and weather right now.

Use the flow trend to confirm the score before you leave. Weather can change the safest and most productive fishing window.

River strategy

Match your section to the rules before you match the hatch.

Henry's Fork is not one uniform fishery. Use the Ashton-area gauge first, then choose a reach that fits current rules, your wade-or-float plan, and the level of pressure you want to handle.

Use RiverReports first for the public chart, then confirm the Ashton-area trend with USGS 13046000.
IDFG applies different rules between Vernon Bridge, Ashton Dam, Riverside, Harriman Ranch, and upstream water.
Riverside and Ashton-area access make this a practical wade or float day, but crowds and reach rules matter more than hero-cast fantasies.
If runoff, weed, or pressure stack against you, move sections early instead of forcing one famous beat all day.

Why this score moved

HeatLowers score

The NWS forecast is near 96F. Without live water temperature, heat risk needs a conservative check.

Best mode nowLowers score

Float: A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.

FlowUse caution

USGS shows 2,300 cfs with a stable over about 6 hours trend. same-date USGS history (1923-2025, 103 readings) puts normal around 1,990 cfs and the upper quartile near 2,250 cfs; today's flow is high for the date. Fishable water may exist, but do not rate it highly without a safe access, clarity, and wading or boat plan.

Public alertUse caution

A heat alert is active near this forecast point, so the score is capped until water temperature and fish-handling risk are checked. NWS alert: Extreme Heat Warning issued July 13 at 2:50AM MDT until July 13 at 9:00PM MDT by NWS Pocatello ID.

SeasonHelps score

Summer: The classic dry-fly season, but it also draws the most pressure and rewards early start times.

Read the water

What changes the plan.

The Ashton corridor is strongest when flows are stable, weed load is manageable, and you know whether you want nymph water, ranch-style dry-fly water, or a float-access day. It loses value quickly if you ignore reach boundaries or show up without a flow-based section plan.

Low clear flow

Best for technical dries and lighter nymph rigs, but it also amplifies crowding and sloppy wading.

Stable medium flow

The most flexible condition for choosing between ranch-style dry fly, nymphing, or short float drifts.

High runoff push

Stay out of side channels and soft banks that make crossings or boat exits feel uncertain.

Heavy weed or moss

Downsize expectations, fish cleaner lanes, and switch reaches if the drift keeps fouling.

Field plan

Fish it with intention.

Best flows

Stable moderate flows that keep weed, side channels, and bank softness manageable while still letting trout hold in predictable lanes.

When to skip

Skip or switch sections when runoff, weed, storms, or crowding make the exact style of fishing you want unrealistic.

Local plan

Check the Ashton graph first, decide whether you want technical dry-fly water or more forgiving riffles, then commit to one section instead of trying to sample the whole river.

Backup water

If Henry's Fork is too crowded or technical for the day you want, look at the South Fork Snake for a different scale or Big Wood for a simpler freestone rhythm after checking current conditions.

Hatches & flies

Bring a flexible box.

TimingWhat to watchUseful flies

SpringMidges, BWOs, and Mother's Day caddis windowsZebra midge, BWO emerger, soft hackle, caddis pupa

Reviewed pattern · report says “Zebra midge”Zebra MidgeLook for a very slim tapered thread body, evenly spaced contrasting wire rib, a small bead, and no tail or wing. The reviewed classic is black with silver wire and a silver bead. Red, olive, brown, glass-bead, jig-hook, resin-coated, or tailed forms must remain labeled variations rather than replacing the classic identity.See photos & how to fish it

Reviewed family · report says “BWO emerger”Blue-Winged Olive PatternsBWO describes a hatch group, not one fly. Nymph, emerger, dry, cripple, and spinner profiles must stay separate because they occupy different parts of the water column.See family guide + 2 more reviewed guides in the Fly Box

Early summerPMDs, caddis, flavs, and green drakesPMD cripple, caddis dry, green drake emerger, split-case nymph

Reviewed family · report says “PMD cripple”Pale Morning Dun PatternsPMD names an insect group, not one fly. Pale nymphs, trailing-shuck emergers, upright or low-riding duns, cripples, and spent-wing spinners stay visibly separate.See family guide

Reviewed family · report says “caddis dry”Caddis Patterns by StageCaddis is not one fly. Larvae live below, pupae and emergers rise through the column, tent-wing adults ride or move on top, and spent forms create other silhouettes.See family guide + 2 more reviewed guides in the Fly Box

SummerCaddis, PMDs, tricos, terrestrialsRusty spinner, trico cluster, ant, beetle, hopper-dropper

Reviewed pattern · report says “Rusty spinner”Rusty SpinnerSplit tails, a slender rusty body, and flat spent wings form the identifying spinner silhouette. Foam-backed and sunken versions are labeled variants.See photos & how to fish it

Reviewed family · report says “trico cluster”Trico PatternsTrico is a hatch family. Sparse nymphs and emergers fish below or in the film; duns and clustered or individual spinners use different surface silhouettes.See family guide + 2 more reviewed guides in the Fly Box

FallBWOs and midgesParachute BWO, RS2, zebra midge, small streamer

Reviewed family · report says “Parachute BWO”Blue-Winged Olive PatternsBWO describes a hatch group, not one fly. Nymph, emerger, dry, cripple, and spinner profiles must stay separate because they occupy different parts of the water column.See family guide

Reviewed pattern · report says “RS2”RS2Start with the beadless architecture: two dark-dun Microfibett tails separated behind a slim, tightly twisted and visibly segmented dubbed abdomen; a fuller thorax; and saddle-hackle web clipped into a short angled wing bud. Rim Chung's original-style form uses natural beaver dubbing and hackle web. CDC- or Antron-wing ties, beads, curved hooks, flash, and tailless Avatar-style flies must remain labeled variations.See photos & how to fish it + 2 more reviewed guides in the Fly Box

Decide whether you are fishing the Ashton water, Riverside reach, or ranch section before rigging up.

Use a conservative first pass on visible risers because repeat casts educate fish quickly here.

Float only if your access, takeout, and reach rules all line up; a famous river still punishes lazy shuttle planning.

If the river is crowded, change water type before changing six flies in a row.

Access & responsibility

Know the entry. Know the exit.

IDFG lists reach-by-reach Henry's Fork rules, including catch-and-release periods, barbless-hook water, no-bait sections, and the seasonal closure through June 14 on the Harriman Ranch section. Check the current 2025-2027 rules before choosing a reach.

Ashton-area public access and dam corridor

Best starting point for gauged water and lower-upper corridor decisions.

Riverside Campground reach

Useful official Forest Service anchor for the upper Ashton corridor and nearby walk-in water.

Red Road Bridge and downstream BLM access

Official lower-river float and bank access that matters when your plan drifts below the classic Ashton water.

Transparent sources

Check the facts behind the plan.

Last material review: 2026-06-02

flowRiverReports: Henry's Fork near Ashton flowUSGS monitoring location: Henrys Fork near Ashton regulationIdaho Fishing Planner: Henrys Fork Snake River accessCaribou-Targhee National Forest Riverside Campground accessBLM Red Road Bridge Boat Access (Henry's Fork)safetyNational Weather Service forecast point near Ashton

Common questions

Before you leave.

Which Henry's Fork reach does this page cover?+

This page is centered on the Ashton gauge corridor, including Ashton Dam access, Riverside water, and the nearby classic upper river decision points.

Can I treat all of Henry's Fork the same way?+

No. IDFG publishes section-specific rules, and the fishing styles change a lot from the lower float river to the technical upper water.

What gauge should I start with?+

Start with RiverReports and USGS 13046000 near Ashton for this page's corridor, then match that reading to your specific section plan.