Main Stem Snake River
MAIN STEM SNAKE RIVER
ReportSEP 9 — 16, 2026
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Flow
3420CFS
SNAKE RIVER NR BLACKFOOT ID
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Water Temp
56.3°F
Updated 2026-09-09
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Weather
47–87°F
Sunny
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Reported By
Bruce Staples
On the water
Water temperature is 56.3°F and flow at the Blackfoot gauge reads 3,420 cfs; below American Falls Dam the staffer reports approximately 8,600 cfs — ideal for floating with all launch sites easily accessible, but wading there remains dangerous. Sunny skies and highs in the low-to-mid 80s are on tap through Thursday.
From the ShopBruce Staples · September 9, 2026
Holiday crowds of Labor Day Weekend are gone and flow has dropped some. Streamer and woolly bugger patterns on sink tip or full sinking lines with stout leaders remain the best producers.
The snowflake dun (Epeorus) emergence is ongoing in good numbers on slower waters from the Tilden Bridge area and on downstream. All boat launches above the Tilden Bridge are open.
Flow below American Falls Dam is about 8,600 cfs, so wading there remains dangerous. This flow is ideal for boating and makes all launch sites easily used.
What's Working — Hot Flies
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Snowflake Dun (Epeorus) | #14–16 | Ongoing emergence in good numbers | Midday–Afternoon on slower water from Tilden Bridge downstream |
| Baetis / Blue-Winged Olive | #18–22 | Seasonal — expect sporadic activity, especially on overcast afternoons | Afternoon |
| Midge | #20–24 | Background activity, typical for September tailwater | Morning and evening |
Best Time Window
- MORNING (7–10 AM): Work streamers and woolly buggers on sink tip or full sinking lines through deeper runs and seams — trout are aggressive before the sun gets high.
- MIDDAY–AFTERNOON (11 AM–4 PM): Shift focus to slower water from Tilden Bridge downstream for the ongoing Epeorus snowflake dun emergence.
- EVENING (5–7 PM): Return to streamer tactics as light drops and trout move back into feeding lanes — gusts up to 20 mph possible, so keep casts tight.
Guide's Tip
From the benchMadison specifically calls out sink tip or full sinking lines with stout leaders for streamer and woolly bugger fishing — don't try to fish these patterns on a floating line at these flows. For the snowflake dun (Epeorus) hatch, target the slower water from Tilden Bridge downstream; the catalog doesn't carry a dedicated snowflake dun pattern, so a light-colored parachute mayfly in #14–16 is your best bet from the shop. All boat launches above Tilden Bridge are open and the current flow makes them all easily accessible.
Main Species
Brown Trout
Rainbow Trout
Yellowstone Cutthroat Trout
