Snake River Fishing Report
Week of August 8, 2026 — August 16, 2026
Current Conditions
Teton Troutfitters guides the South Park to Alpine reach. Upriver conditions shown for reference.
The tailwater below Jackson Lake Dam is discharging a stable 4,880 CFS with water clarity exceeding six feet. Hypolimnetic releases keep stream temperatures in the favorable 48–66°F range, preserving active trout feeding behavior even during afternoon ambient heat peaks. Cutthroat are concentrated along subtle seam lines, submerged timber hazards, and side-channel junction pools. Mid-morning PMD emergences from 10:00 AM to 1:30 PM draw fish into subtle rise lines along foam drop-offs. Due to high recreational boat traffic, tailwater cutthroat have become selective — downsizing leader tippets to 5X and fishing low-profile emergers or CDC patterns yields higher catch rates. Walk-and-wade angling is viable directly below the dam outlet. Drift-boat floats remain the most productive method for covering the extensive braided water.
The middle Snake River carries approximately 5,210 CFS through braided channels, expansive gravel bars, and logjams — a significant drop from the 6,190+ CFS of recent weeks. Water clarity remains high at four to five feet of visibility. This reach represents classic dry-fly floating water, where large foam hoppers and stonefly attractors dropped near willow-lined banks regularly trigger surface takes. During the warm spell (Aug 8–11), effort should concentrate on fast, oxygenated pocket water and shaded margins of island braids. As cloud cover settles over the valley mid-week (Aug 12–15), trout move out of deep resting holes onto shallow gravel shelves to target emerging Baetis and falling terrestrial insects. The lower flows have exposed more structure and narrowed the active channels, creating defined target zones along gravel bars and cut-banks.
The lower reaches carry approximately 6,300–6,800 CFS below Flat Creek, expanding to 6,500 CFS near Alpine Reservoir. Clarity remains good at three to four feet. The broader, unshaded nature of these lower channels subjects the water to greater solar heating, with temperatures reaching 68°F by early afternoon during the warm phase (Aug 8–11). Floating parties should launch at dawn (6:30–7:00 AM) and complete fishing by 1:30 PM. Casting weighted streamers — Sparkle Minnows, Sculpzillas, or Double Bunnies — tight to plunge walls and boulder fields produces large cutthroat and resident brown trout before direct sunlight strikes the water. The mid-week cold front (Aug 12–15) lowers peak temperatures and relaxes thermal constraints, allowing extended sessions through the afternoon.
What's Hatching
Terrestrials (Hoppers, Ants, Beetles)
Heavy10:00 AM – 3:30 PM
Terrestrial insects are the dominant surface food source as valley grasses dry under mid-summer sun. Southwest winds averaging 10–14 mph frequently deposit grasshoppers, flying ants, and beetles into bankside seams and willow overhangs. Fine-spotted cutthroat target these large terrestrial profiles aggressively, feeding within inches of steep dirt banks and overhanging willows.
Pale Morning Duns (PMDs)
Heavy9:30 AM – 1:30 PM
PMDs continue to hatch during mid-morning hours in gravel riffles, producing dense dun surface flights that peak between 9:30 AM and 1:30 PM. Cutthroat key on emergers trapped in the surface film along foam drop-offs. On tailwater flats below the dam, selective cutthroat demand low-profile emergers and CDC cripple patterns fished on 5X tippet.
Caddis (Spotted Sedges)
Heavy6:00 PM – Dusk
Evening flights of spotted sedges and tan caddis intensify between 6:00 PM and full dark. Egg-laying females skittering across glassy tailouts and pool heads trigger rapid, aggressive rise forms. This secondary evening feeding window extends the fishing day on reaches where water temperatures have cooled.
Blue-Winged Olives (Baetis)
Moderate11:00 AM – 3:00 PM (Overcast)
The arrival of cloud cover and rain from August 12 through August 15 will trigger concentrated Baetis emergences in slow-moving eddies and tail-outs. BWO hatches respond strongly to low barometric pressure and overcast skies. Fish move out of deep resting holes onto shallow gravel shelves and foam lines to target these small mayflies during the cool, rainy mid-week period.
Golden Stonefly
Moderate8:00 AM – 11:30 AM
Late-season adult stoneflies provide lingering morning action along structural banks, canyon walls, and willow-heavy vegetation. Intensity continues to taper as the hatch transitions toward its seasonal conclusion, but morning surface activity along fast pocket water and boulder edges remains consistent.
Yellow Sallies
Moderate10:00 AM – 3:00 PM
Small stoneflies continue emerging through the midday and afternoon hours. Adults flutter over moderate-velocity currents and riffle heads, bridging the gap between the morning stonefly window and the evening caddis flight.
What's Producing
Dry Flies
Primary foam attractor and dry-dropper anchor. Large profile mimics grasshoppers and Golden Stones along bankside structure. Supports heavy tungsten droppers on 18–30 inches of 4X fluorocarbon.
Cast tight to grassy undercut banks with drift placement within six inches of overhanging vegetation during peak terrestrial hours (10:00 AM–3:30 PM).
Low-profile silhouette for the mid-morning PMD hatch. Excels on tailwater flats where selective cutthroat demand flush-floating presentations on 5X tippet.
Fish during the overcast mid-week period (Aug 12–15) when Baetis emergences produce concentrated rise cycles in slow eddies and smooth tail-outs.
Evening caddis flights from 6:00 PM to dusk in tail-outs, pool heads, and fast riffles.
Dead-drift along undercut banks and willow margins where southwest winds deposit flying ants into bankside seams.
Nymphs & Droppers
Heavy stonefly dropper suspended 18–30 inches below the dry fly on 4X fluorocarbon. Target deep seam lines along gravel bars and pocket water.
Slender, fast-sinking jig nymph for mid-river seams and gravel-bar drop-offs. Effective throughout the day during high-sun periods.
Sleek, epoxy-coated body drops to depth in heavy current. Doubles as an effective Baetis nymph during overcast BWO windows.
Streamers
Strip tight to plunge walls and boulder fields during the early-morning streamer window (6:30–9:30 AM) while water temperatures sit at daily lows.
Articulated sculpin pattern for deep undercut banks and drop-offs. Triggers reaction strikes from large cutthroat and resident brown trout.
Rabbit-strip streamer with heavy undulating action. Retrieve on intermediate sink-tips along deep canyon walls before direct sunlight strikes the water.
Emergers
Baetis emerger for the overcast-triggered BWO hatch windows (Aug 12–15). Fish in soft eddies and smooth tail-outs on 5X–6X fluorocarbon.
Caddis emerger with trailing shuck for selective fish in glassy tailouts during the evening flight. Simulates a partially emerged pupa.
Best Time and Section This Week
Guide's Take
This is a two-phase week, and both phases are outstanding. The first half brings classic August heat — 85–87°F highs — which means strict early launches and disciplined thermal cutoffs. Our guides are putting boats in at 6:30 AM and finding cutthroat stacked along every bankside seam, aggressively taking hoppers, ants, and beetles before the sun gets high. The real story is the cold front arriving Wednesday. When those highs drop from 87°F to the mid-60s with rain and cloud cover, it transforms the fishing. BWOs are coming back in force for the first time since mid-July. Trout are going to move out of deep resting holes onto shallow gravel shelves and foam lines, and we're expecting full-day sessions with overlapping PMD, BWO, and terrestrial activity. Flows at Moose have dropped to 5,210 CFS — the lowest of the season — and it's opening up structure we haven't been able to fish all summer. The PMD Compara-dun and RS2 are earning spots in the fly box for the selective tailwater cutthroat. Flat Creek continues to fish beautifully in its second week.
Next Week's Outlook
The mid-week low-pressure trough is the marquee event. Cloud cover and rain from August 12 through August 15 will drop highs into the upper 60s, lower peak water temperatures back into the optimal 54–60°F range, and trigger concentrated BWO hatches alongside sustained PMD and terrestrial activity. This creates the potential for full-day fishing schedules — a rare opportunity during August. As the system clears by Sunday, August 16, temperatures will climb back toward the mid-70s. Flows will continue to recede as Jackson Lake storage is drawn down. Terrestrial fishing will remain the dominant surface strategy into late August. Flat Creek is fishing well in its second week under trophy catch-and-release regulations. High-elevation tributaries — the Gros Ventre, Pacific Creek, and Granite Creek — offer cold-water refuge during hot afternoon periods.
Conservation Note
During the warm phase (Aug 8–11), afternoon water temperatures on lower reaches below South Park approach 68–69°F. When water exceeds 68°F, trout experience severe physiological stress — their recovery capacity declines sharply, and post-release mortality increases significantly even if the fish swims away. 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 when air temperatures exceed 80°F. The mid-week cold front (Aug 12–15) relaxes thermal constraints and allows extended angling schedules, but continue monitoring water temperatures on all reaches.
Common Questions This Week
How do the two weather phases affect fishing this week?
This week splits into two distinct phases. From August 8 through August 11, hot conditions (85–87°F highs) require strict early launches at 6:30 AM, morning streamer and dry-dropper presentations, and thermal cutoffs by 1:30–2:00 PM on lower reaches. From August 12 through August 15, a low-pressure trough drops highs into the upper 60s with cloud cover and rain. This cooling trend lowers water temperatures into the optimal 54–60°F range, allowing full-day fishing schedules and triggering concentrated BWO hatches alongside sustained PMD and terrestrial activity. By Sunday, August 16, clearing skies and warming temperatures return to the mid-70s.
What patterns do I need for the returning BWO hatch?
The overcast conditions from August 12–15 will trigger concentrated Baetis emergences in slow eddies and tail-outs. Carry a BWO Sparkle Dun (#20) for surface-feeding fish and an RS2 (#20) as a trailing emerger on 5X–6X fluorocarbon. A Tungsten Perdigon (#14–18, Olive) doubles as a Baetis nymph dropper. BWOs respond strongly to low barometric pressure and cloud cover — watch for subtle rise forms in glassy backwaters and foam lines during mid-morning through early afternoon.
What does the flow drop to 5,210 CFS mean for fishing?
Flows at Moose have dropped from 6,190 CFS to 5,210 CFS — the lowest reading of the season. Lower flows expose more mid-river structure — gravel bars, cobble runs, logjam edges, and side-channel braids — that were submerged during higher-water weeks. This creates more defined target zones where cutthroat concentrate in predictable current seams. Drift-boat navigation requires closer attention to shallow braids, but the reduced velocity makes bankside presentations more effective. Terrestrial drifts along willow margins and grassy cut-banks are especially productive as the narrower active channels concentrate food delivery.
A mid-week cold front is about to unlock full-day fishing with overlapping PMD, BWO, and terrestrial hatches — conditions we rarely see in August. Flows at Moose have dropped to 5,210 CFS, exposing structure we haven't fished all summer. Our guides are running early-launch floats on the cold tailwater and gearing up for outstanding overcast dry-fly days mid-week. Book your float before the late-August dates are gone.
