Main Stem Snake River
MAIN STEM SNAKE RIVER
ReportSEP 30 — OCT 7, 2026
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Flow
1180CFS
SNAKE RIVER NR BLACKFOOT ID
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Water Temp
56.3°F
Updated 2026-09-30
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Weather
46–78°F
Sunny
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Reported By
Bruce Staples
On the water
Outflow from American Falls Reservoir has dropped as irrigation season winds down, leaving the river above the reservoir at low, wadeable flows with 56.3°F water and widespread access. Below the dam, flows run around 4,400 cfs — prime for boat anglers, but wading there remains dangerous.
From the ShopBruce Staples · September 30, 2026
Outflow has dropped from American Falls Reservoir and water storage is ramping up as irrigation needs diminish. Widespread wading locations are present as the river above the reservoir has low flow. This means safer wading and more access to the river above.
Streamer and woolly bugger patterns on sink tip or full sinking lines with stout leaders remain the best producers. All boat launches above the Tilden Bridge are open. Flow below American Falls Dam is about 4,400 cfs, so wading there remains dangerous but is ideal for boating.
What's Working — Hot Flies
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Streamers / Baitfish | #4–6 | All day | Morning through afternoon |
| Leech / Woolly Bugger | #6–14 | All day | Low-light edges — early morning and evening |
| Sculpin | #4–6 | Active | Throughout the day on sinking lines |
Best Time Window
- MORNING (first light to 9 AM): Prime low-light window for streamer and leech patterns on sinking lines — fish are most aggressive before the sun hits the water.
- AFTERNOON (1 PM to dusk): Sunny skies and 75°F highs keep fish active; work the deeper runs and shaded banks with sculpin and minnow streamers.
- EVENING (last hour of light): Dropping temperatures trigger a second aggressive feeding window — swing streamers through the tailouts before dark.
Guide's Tip
From the benchRig a sink tip or full sinking line with a stout leader — that's the setup Madison says is producing right now. Classic woolly bugger patterns (not stocked in the catalog) are also in the mix, so don't leave home without a few in olive and black. Above the reservoir, take advantage of the low, clear water to access wading spots that are normally tough to reach. Boaters targeting the water below American Falls Dam should note all launches above Tilden Bridge are open.
Main Species
Brown Trout
Rainbow Trout
Yellowstone Cutthroat Trout
