Snake River Fishing Report
Week of August 2, 2026 — August 9, 2026
Current Conditions
Teton Troutfitters guides the South Park to Alpine reach. Upriver conditions shown for reference.
The upper tailwater is operating at approximately 4,810 to 4,910 CFS with exceptional clarity exceeding six feet of visibility. Hypolimnetic releases from Jackson Lake maintain water temperatures well within the optimal range for native cutthroat, resetting to 54–58°F each morning thanks to strong nocturnal radiational cooling (overnight lows in the high 30s to low 40s). Trout are positioned along structural banklines, drop-offs, and seam lines, taking both surface attractors and sub-surface nymphs. Cold contributions from Pacific Creek (104 CFS) buffer thermal increases through the reach. Walk-and-wade angling is viable directly below the dam outlet on gravel bars, while drift-boat floats remain the most productive method for covering the extensive braided water.
The mainstem through Grand Teton National Park is flowing at 6,190 to 6,470 CFS and is clear, stable, and in prime summer form. Water temperatures range from 60°F to 66°F, with cold contributions from Pacific Creek and the Buffalo Fork helping buffer thermal increases. Wide gravel-bar braids and extensive side channels provide habitat where fish actively feed during morning and midday emergence windows. Drift boats provide the most effective coverage, with oarsmen holding lines 10 to 15 feet off cut-banks. Cutthroat hold in current velocities of 1.5 to 2.5 mph, avoiding the stronger central channel. Golden Stonefly activity continues along vegetated banks during morning hours, after which trout transition to feeding on PMD duns, emergers, and terrestrials in side-channel riffles and along willow margins.
Below the Gros Ventre River (~498–586 CFS) and Flat Creek (~136–144 CFS) confluences, streamflow reaches 7,190 to 7,330 CFS near South Park. Water clarity averages three to four feet. The broad, unshaded character of this lower river section subjects it to rapid solar heating, with peak afternoon water temperatures approaching 68°F. This is especially concerning as ambient air temperatures push into the upper 80s from Thursday through Saturday. Angling must be concentrated in the early morning hours, with all fishing ceasing by 1:30 PM. Morning fishing is productive along shadow-lined canyon walls and deep bankside troughs. Streamers retrieved on intermediate sink-tips trigger reaction strikes from cutthroat and resident brown trout along deep drop-offs before 10:00 AM.
What's Hatching
Pale Morning Duns (PMDs)
Heavy10:00 AM – 2:00 PM
PMDs remain the predominant mayfly hatch across the system at peak intensity. Nymphs migrate toward shallow gravel riffles and mid-river seams mid-morning, with dense dun surface flights peaking between 10:00 AM and 2:00 PM. Cutthroat key on emergers trapped in the surface film in glassy tailouts and back-eddy foam lines. On tailwater flats below the dam, selective cutthroat demand longer, finer leaders and flush-floating cripple patterns.
Terrestrials (Hoppers, Ants, Beetles)
Heavy11:00 AM – 3:00 PM
Terrestrial insects have become a central dietary component for Snake River cutthroat as summer heat dries valley floor vegetation. Grasshoppers in the #10–14 size class are abundant in grassy meadows, while carpenter ants and foam beetles are pushed into margin currents by thermal updrafts and afternoon wind gusts. Cutthroat have adjusted holding positions, feeding within inches of steep dirt banks and overhanging willows to intercept falling terrestrials.
Caddis (Spotted Sedges)
Heavy6:00 PM – Dark
Evening flights of spotted sedges and tan caddis intensify between 6:00 PM and full dark. Egg-laying females skittering across glassy tailouts trigger rapid, aggressive rise forms from fine-spotted cutthroat. This secondary evening feeding window extends the fishing day for anglers on reaches where water temperatures have cooled.
Golden Stonefly
Moderate6:00 AM – 10:00 AM
Late-season adults remain along willow-heavy banks and river-edge vegetation. Mature females are ovipositing during warm morning hours, prompting surface rises in bankside eddies and foam lines. While peak emergence occurred in late June and early July, the hatch continues to produce consistent early-morning surface activity along canyon walls and vegetated shorelines.
Yellow Sallies
Moderate11:00 AM – 3:00 PM
Small stoneflies continue emerging steadily through the afternoon. Adults flutter over moderate-velocity currents and riffle heads, providing a consistent food source that bridges the gap between the morning stonefly window and the evening caddis flight.
What's Producing
Dry Flies
Primary foam attractor and dry-dropper anchor. Supports heavy tungsten droppers while serving as a high-visibility surface target along bankside structure.
Peak-season grasshopper pattern for the dominant terrestrial window. Cast tight to grassy banks with drift placement within six inches of overhanging vegetation.
Match the peak midday PMD hatch on riffle edges, seam lines, and foam eddies. The cripple variation excels on tailwater flats where cutthroat feed selectively.
Fish the intense evening caddis flights from 6:00 PM to dark in tailouts, glassy slicks, and fast riffles.
Dead-drift along undercut banks and willow margins where heat-driven ant falls create consistent terrestrial drift into margin currents.
Foam beetle pattern for the building terrestrial bite. Fish tight to overhanging willows and steep dirt banks during midday wind gusts.
Micro ant pattern for selective cutthroat on tailwater flats and Flat Creek sight-fishing. Flush-floating profile in the surface film.
Nymphs & Droppers
Heavy stonefly dropper suspended 18–24 inches below the dry fly on 3X–4X fluorocarbon. Target deep seam lines along gravel bars.
Slender, fast-sinking jig nymph for deep seam lines and pocket water. Rides hook-point-up to reduce snags on cobble substrate.
Sleek, epoxy-coated body drops immediately to depth in heavy 6,000+ CFS mainstem current without dragging down the dry fly.
Suspend below the indicator fly in active riffle heads to intercept emerging PMD nymphs during the peak midday hatch window.
Streamers
Strip on intermediate sink-tips along steep canyon drop-offs and deep bank structure during the early-morning window (6:00–8:00 AM).
Retrieve near deep structure and boulder banks under low-light conditions. Triggers reaction strikes from cutthroat and resident brown trout.
Emergers
Caddis emerger for selective fish in glassy tailouts and slicks during the evening flight. Trailing shuck imitates a partially emerged pupa.
Best Time and Section This Week
Guide's Take
This is peak summer fishing on the Snake. The early-week forecast is exceptional — 75°F highs with overnight lows dipping into the high 30s, which means the river is resetting to a perfect 54–58°F by dawn. Our guides are launching at first light and finding cutthroat stacked in every bankside seam and foam line. Terrestrials have fully taken over as the dominant surface food. We're putting Morrish Hoppers and Parachute Foam Ants on the end of the tippet and watching cutthroat hold within inches of the dirt banks, intercepting everything that hits the water. PMDs are still blanket-hatching at peak density from 10:00 to 2:00. The fly box has evolved — Beetle-Mania, Cinnamon Ants, and the X-Caddis are all new additions that are earning their keep. Flat Creek opened on August 1 and the sight-fishing is already outstanding for trophy cutthroat on long leaders and 5X–6X fluorocarbon. Late week warms into the upper 80s, so strict Hoot Owl discipline will be essential Thursday through Saturday.
Next Week's Outlook
A pronounced warming trend will push air temperatures from the mid-70s early in the week to the upper 80s by Thursday through Saturday. Late-week thermal management will become critical on Reach 3 as afternoon water temperatures approach 68°F. Early-week conditions are ideal, with strong nocturnal cooling resetting morning water temperatures into the optimal 54–58°F range. Terrestrial fishing will continue to dominate as valley vegetation dries further. PMDs will sustain at peak intensity. Golden Stoneflies continue their late-season wind-down but still produce morning surface takes. Flat Creek is fishing well in its opening week, and the technical sight-fishing will only improve as cutthroat settle into late-summer feeding rhythms. High-elevation tributaries — the Gros Ventre, Pacific Creek, and Granite Creek — offer cold-water refuge alternatives during hot afternoons.
Conservation Note
As ambient air temperatures push into the upper 80s from Thursday through Saturday, lower mainstem reaches below South Park will see afternoon water temperatures approach the critical 68°F threshold. When water exceeds 68°F, trout experience severe physiological stress — lactic acid builds rapidly in muscle tissue and low dissolved oxygen prevents recovery, leading to delayed mortality. On Reach 3, complete all fishing by 1:30 PM. On Reaches 1 and 2, cease by 2:00 PM. Use 3X–4X fluorocarbon tippet to keep fight times under 60–90 seconds. Keep fish fully submerged in rubber-mesh landing nets and do not remove fish from the water for photographs when air temperatures exceed 80°F. For full-day options, focus exclusively on cold tailwater below Jackson Lake Dam or high-elevation tributaries where water temperatures remain below stress thresholds.
Common Questions This Week
How does this week's weather affect fishing strategy?
Early in the week (Monday–Wednesday), conditions are ideal: highs in the mid-70s with overnight lows dipping into the high 30s to low 40s, resetting river temperatures to an optimal 54–58°F by dawn. These mornings offer extended fishing windows through 2:00 PM. By Thursday, ambient temperatures push into the mid-to-upper 80s, significantly accelerating afternoon thermal loading on the lower river. Late-week strategy should emphasize strict early launches (6:00–7:00 AM), concentrating on the cold upper tailwater and ceasing all fishing on Reach 3 by 1:30 PM.
How is Flat Creek fishing in its opening week?
Flat Creek opened on August 1 under strict trophy regulations: artificial flies only, 100% catch-and-release. This spring creek features slow-moving, meandering water with highly educated cutthroat trout. Success demands a low-profile bankside approach, extended leaders (12–15 feet ending in 5X–6X fluorocarbon), and stealthy long casts. Primary hatches include Pale Morning Duns (#16–18), micro-caddis, and small terrestrials — size #16–18 ants, beetles, and flush-floating PMD cripples are the top patterns. Streamflow is stable at 136–144 CFS with cool groundwater temperatures.
What terrestrial patterns should I carry this week?
The terrestrial bite is the dominant surface game right now and requires a diverse selection. For grasshoppers, carry Morrish Hoppers (#10–12) for aggressive bankside strikes along grassy meadows. For ants, the Parachute Foam Ant (#14–16) and Cinnamon Ant (#16–18) cover the full size range from bankside undercut structure to tailwater flats. The Beetle-Mania (#14–16) is a foam beetle that produces during midday wind gusts. Cast all terrestrials with tight drift placement within six inches of overhanging bankside vegetation — cutthroat are feeding within inches of steep dirt banks and willows.
Terrestrials are the headline act — hoppers, ants, and beetles are producing explosive bankside strikes. PMDs are blanket-hatching at peak density. Flat Creek just opened for trophy sight-fishing. Our guides are launching at dawn on the cold tailwater, and the morning dry-fly window is the best of the summer season. Book your early-launch float before the August dates are gone.
