Idaho ·
Snake River Fly Fishing Report - September 20, 2026

SNAKE RIVER
ReportSEP 20 — 27, 2026
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Flow
2840CFS
SNAKE RIVER AT MOOSE, WY
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Water Temp
55.2°F
Updated 2026-09-19
☀️
Weather
35–68°F
Areas Of Fog
💧
Clarity
Clear
Check post-storm
Flow at Moose is 2,840 CFS at 10.1 ft — well down from summer highs and concentrating cutthroat, brown, and rainbow trout tight to the banks in classic lies. Water temp is 55.2°F, right in the sweet spot for aggressive feeding and active hatches.
What's Working — Hot Flies

Parachute - Blue Wing Olive #22
#22

Juju Baetis Tungsten #22
#22
Barr's Flashback Emerger - BWO #22
#22

Bionic Ant 2.0 - Black #16
#16

Bionic Ant 2.0 - Brown #12
#12

Corn-fed Caddis (CDC) Tan #20
#20

Corn-fed Caddis (CDC) Olive #20
#20

Coffey's CH Sparkle Minnow Sculpin #6
#6

Sculpzilla - Olive #4
#4

Egan's Thread Frenchie Jig - Olive #12
#12

Egan's Frenchie #12
#12

Top Secret Baetis #16
#16
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Blue-Winged Olive (Baetis) | 20-22 | Heavy | 10 AM - 2 PM |
| Caddis | 16-18 | Moderate | 4 PM - 7 PM |
| Terrestrials (Ants) | 14-16 | Moderate | 11 AM - 4 PM |
| Midge | 20-22 | Light | 8 AM - 11 AM |
| Sculpin / Baitfish | 4-6 | Moderate | 6 AM - 9 AM |
Best Time Window
- 7 AM - 10 AM: Nymph the deep bank slots with Frenchies and Baetis patterns before fog lifts; fish are active and holding tight to structure.
- 10 AM - 2 PM: Prime dry fly window as BWO hatch fires under overcast skies; target flat seams along cut banks with a #22 Parachute BWO.
- 5:30 PM - 7:30 PM: Evening caddis activity in the riffles and tailouts; swing a CDC Caddis or strip a streamer through the deep outside bends for aggressive brown trout.
Guide's Tip
From the benchWith fog persisting until 11 AM and flows at a very fishable 2,840 CFS, start your morning nymphing the deeper bank-side slots with a Frenchie or Baetis nymph at 2-3 feet of depth — fish are stacked tight to structure. Once the fog lifts and BWOs start popping around 10-11 AM, switch to a dry and work the flat, slow seams along cut banks with a long, drag-free drift; these fish have seen pressure and will refuse anything with a hint of drag. In the afternoon, if the slight chance of thunderstorms holds off, terrestrials along grassy banks can produce some of the biggest browns of the day. Save your streamer rod for the final 90 minutes of light — swing a Sculpzilla or Sparkle Minnow through the deep outside bends where big browns are staging for fall.
Main Species
Snake River Fine-Spotted Cutthroat Trout
Brown Trout
Rainbow Trout
