Snake River Fishing Report
Week of September 26, 2026 — October 4, 2026
Current Conditions
Teton Troutfitters guides the South Park to Alpine reach. Upriver conditions shown for reference.
Dam outflows have settled to 1,150 CFS at Moran with ice-clear visibility exceeding eight feet—the lowest and clearest conditions of the year. The dramatic stage drop has dewatered lateral side channels and perimeter gravel bars, consolidating streamflow within primary channel troughs and exposing extensive wading corridors from the dam outlet through Cattleman's Bridge. Cutthroat trout hold in tailout slicks, mid-river gravel depressions, and drop-offs. Morning hours favor delicate midge and Baetis nymph presentations on 5X fluorocarbon beneath low-profile indicators. When the overcast front arrives (Sep 28–30), rising pods of cutthroat trout require matched-hatch Parachute BWOs (#20) and CDC emergers in foam lines and glide seams. Below Pacific Creek, the braided channel has contracted to its narrowest of the season, concentrating fish along inside gravel seams, submerged logjams, and deep eddy seams.
Discharge at Moose has receded to 1,880 CFS at a stage of 9.55 feet—well below the historical mean of 10.46 feet. Many side channels and braids that were fishable at 4,000+ CFS are now dewatered or too shallow to float. Drift boat operators must read the main channel carefully to avoid stranding on newly exposed gravel shoals. Cutthroat trout have moved off bank structure entirely and are stacked in pool heads, along mid-river gravel drop-offs, and in deep eddy seams. Extensive gravel bars along Deadman's Bar and Moose Landing provide excellent walk-and-wade access. Tandem dry-fly rigs cast down foam lines during the overcast front (Sep 28–30) produce steady surface strikes from rising cutthroats feeding on BWOs and Mahogany Duns.
Canyon flows have contracted to 3,220 CFS above Alpine Reservoir, maintaining ideal autumn float-fishing conditions through sheer limestone walls, deep boulder runs, and large eddy pools. This reach holds high densities of resident brown trout entering full pre-spawn hyperphagic mode—staging in deep scour pools, along cliff faces, and near boulder shelves. Sinking-tip lines paired with articulated streamers stripped through deep structure produce aggressive territorial strikes. Dropping light levels during the mid-week front amplify the streamer bite. Midday hours offer dry-fly opportunities using Mahogany Duns and October Caddis along shaded canyon walls.
What's Hatching
Blue-Winged Olives (Baetis)
Heavy11:30 AM – 3:30 PM
Baetis tricaudatus (#18–22) reaches peak autumn surge during the cold front (Sep 28–30). High atmospheric humidity and low solar insolation impede the dun's ability to dry its wings, forcing subimagos to drift along the surface film for extended distances. Cutthroat trout form rising pods in slow foam lines, back-eddy slicks, and gravel-shelf seams. The undisputed dominant hatch through early October.
Mahogany Duns (Paraleptophlebia)
Heavy1:00 PM – 3:30 PM
Paraleptophlebia bicornuta (#14–16) strengthens to heavy density alongside Baetis, emerging through cobble riffles, glide transitions, and gravel bars during peak afternoon hours. The darker, reddish-brown profile provokes aggressive surface takes along seam margins where swift currents meet moderate-velocity water. Running concurrently with BWOs, creating multi-species surface feeding opportunities.
October Caddis (Dicosmoecus)
Sporadic4:30 PM – Dusk
Large orange caddisflies (#8–10) emerge sporadically from late afternoon through dusk along boulder plunge pools and bank seams. Ovipositing females fluttering over the surface draw strikes from pre-spawn brown trout and large cutthroats seeking a caloric meal before nightfall. Building through early October.
Midges (Chironomidae)
Light8:30 AM – 11:30 AM
Consistent daily Chironomid activity (#20–24) in tailwater pools below Jackson Lake Dam, slow spring creek glides, and backwater eddies. A reliable morning dietary constant that provides the first surface feeding opportunity each day before major mayfly emergences begin.
Tricos (Tricorythodes)
Sporadic9:00 AM – 10:30 AM
Tricorythodes (#20–22) produce minimal, localized morning spinner falls in low-velocity backwaters and spring creeks. The seasonal Trico window is concluding as overnight freezes suppress remaining populations. Last effective opportunities on Flat Creek during calm morning hours.
What's Producing
Dry Flies
Primary match-the-hatch pattern for peak autumn Baetis emergence; most effective during the overcast front Sep 28–30 when dense hatches concentrate in foam lines, eddy slicks, and glide seams from 11:30 AM to 3:30 PM
Flush-floating trailing fly in tandem dry rigs; sits within the surface film to deceive selective cutthroat trout refusing higher-riding parachute patterns; trail 18–24 inches behind a Mahogany Dun locator on 6X tippet
Alternative BWO dun imitation for slow glassy margins and tail-out slicks; effective when trout key on crippled or partially emerged duns during concentrated hatches
Mahogany Duns now at heavy density—target cobble riffles, glide transitions, and gravel bars 1:00–3:30 PM; doubles as high-visibility locator fly in tandem rigs with a trailing CDC Baetis or emerger
October Caddis searching pattern for the dusk window; large orange profile matches ovipositing Dicosmoecus females fluttering over boulder plunge pools and bank seams; draws strikes from pre-spawn browns and large cutthroats
Realistic October Caddis adult imitation; cast along shaded canyon walls and riffle crests during the final light from 4:30 PM to dusk; the large caloric profile provokes committed surface takes
Early morning midge pattern for tailwater pools and slow spring creek glides; covers the consistent Chironomid baseline from 8:30–11:30 AM before major mayfly emergences begin
Nymphs & Droppers
Jigged tungsten-bead nymph for penetrating reduced autumn currents along gravel-bar breaks and scour pools; effective beneath low-profile indicators or buoyant dry flies during non-hatch windows
Weighted Baetis nymph imitation for subsurface presentations ahead of the hatch; particularly effective during the cold-front mornings (Sep 28–30) when trout feed below the surface before committing to duns
Simple, effective Chironomid pupa imitation for tailwater slicks and slow eddies during cold morning hours; fish as a dropper beneath a dry fly or under a micro-foam indicator in water 2–3 feet deep
Streamers
Strip along deep canyon walls and pool tail-outs on 150–250 grain sink-tip lines; pre-spawn brown trout at peak aggression during the mid-week front as dropping light levels intensify territorial behavior
Articulated rabbit-strip pattern for deep scour pools and boulder shelves; sharp rhythmic strips followed by brief pauses provoke territorial reactions from staging brown trout near tributary confluences
Weighted sculpin imitation cast tight to limestone cliff faces and rock ledges; short 4–5 ft 0X–2X fluorocarbon leaders keep the fly tracking deep through pre-spawn brown trout staging zones
Emergers
Unweighted BWO emerger for the film; effective as a trailing pattern or fished solo to trout sipping just below the surface during concentrated Baetis emergences; critical when fish refuse dun profiles
Best Time and Section This Week
Next Week's Outlook
The Snake River has arrived at its autumn baseflow equilibrium. Jackson Lake Dam outflows settling to 1,150 CFS at Moran and 1,880 CFS at Moose—well below the historical mean—have produced the clearest water, the most accessible wading, and the most concentrated fish populations of the entire season. The channel contraction narrows aquatic drift into defined feeding lanes, creating favorable conditions for both dry-fly and nymph presentations. Three tactical phases define the week: mild autumn conditions on September 26–27 favor mid-river seam prospecting with attractor dry-dropper rigs. The strong cold front from September 28–30, bringing hard freezes (24–29°F overnight), overcast skies, and daytime highs in the mid-50s, triggers peak BWO and Mahogany Dun emergences—two heavy hatches running simultaneously through foam lines and cobble riffles. From October 1 onward, stable high pressure delivers crisp mornings and sunny afternoons ideal for sight-fishing rising trout in side channels, tailwater flats, and spring creeks. October Caddis continue building at dusk. Terrestrial fishing has definitively concluded for the 2026 season. Pre-spawn brown trout in the canyon reach remain at peak aggression. Water temps stabilize between 38–55°F with peak feeding from 11:30 AM to 4:30 PM.
Conservation Note
Baseflow conditions at 1,880 CFS at Moose have exposed extensive gravel bars and concentrated flows into primary channel troughs. Brown trout are actively staging for their autumn spawning run near tributary mouths—identify and avoid newly excavated spawning redds, visible as clean, light-colored gravel depressions in shallow riffles and tailouts. Wading through or casting over active redds disrupts spawning and crushes fertilized eggs. Critical cold-weather handling: with overnight lows dropping to 24–29°F, never expose fish to sub-freezing air—gill damage and eye crystallization can occur within seconds. Keep trout fully submerged in rubber-mesh nets during hook extraction. Handle with clean, wet hands only. Use barbless hooks and appropriate tippet strengths to land fish quickly. Wade anglers should use studded boots and wading staffs on slippery, newly exposed cobble.
Common Questions This Week
What hatches are active on the Snake River this week?
Five active insect groups. Blue-Winged Olives (#18–22) reach peak autumn density during the cold front (Sep 28–30) with heavy emergence in foam lines and eddy slicks from 11:30 AM to 3:30 PM. Mahogany Duns (#14–16) have strengthened to heavy, emerging alongside BWOs through cobble riffles from 1:00–3:30 PM—two heavy hatches running simultaneously. October Caddis (#8–10) continue building at dusk with sporadic but growing activity. Morning Midges (#20–24) provide consistent early surface opportunities. Tricos are concluding their seasonal run. Terrestrial fishing has definitively ended for the 2026 season following repeated hard freezes.
Can I wade fish the Snake River this week?
This is the best walk-and-wade access of the entire 2026 season. Both the upper tailwater at Moran (1,150 CFS) and the middle Snake at Moose (1,880 CFS) are rated excellent for wading, with extensive gravel bars exposed along the dam outlet, Cattleman's Bridge, Deadman's Bar, and Moose Landing. The river stage at Moose has fallen well below the historical mean, opening corridors that have been submerged since June. The canyon reach (3,220 CFS) is best accessed by drift boat, though local wade access exists. Tributaries including the Gros Ventre (204–227 CFS) and Flat Creek offer excellent walk-and-wade sight fishing through October 31.
How should I handle fish in freezing temperatures?
With overnight valley lows dropping to 24–29°F, cold-weather fish handling is critical. Never expose trout to sub-freezing air—gill damage and eye crystallization can occur within seconds. Keep fish fully submerged in a knotless rubber-mesh net during hook extraction. Touch fish only with clean, wet hands to preserve their protective slime coat. Use barbless hooks across all pattern styles to facilitate rapid underwater removal. Use appropriate tippet strengths to land fish quickly, avoiding prolonged fights that cause lactic acid buildup in cold water.
What flies should I bring for October Caddis?
October Caddis (Dicosmoecus atripes) are large, orange caddisflies in #8–10 that emerge from late afternoon through dusk. Carry Orange Stimulators (#8–10) as a searching pattern and Morrish October Caddis (#8–10) for a more realistic adult imitation. Fish them along shaded canyon walls, boulder plunge pools, and bank seams during the final hour of light. Use a 9-foot leader tapered to 3X–4X monofilament. The large silhouette draws strikes from pre-spawn brown trout and large cutthroats seeking a caloric meal before nightfall.
Two heavy hatches running simultaneously, October Caddis building at dusk, pre-spawn browns at peak aggression, and the best wade access of the year—late September into October is the Snake River at its finest. Book your guided float or walk-and-wade trip before winter closes the season.
