Big Thompson River Report

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Big Thompson River Report

9-3-2026

Flows are back up to 133, but expect it not to last too long. For now, fish will be in areas sheltered from the current, so think closer to shore, behind cover, etc. Once the flows drop, they will be more spread out, but concentrate your efforts in deeper water. Right now, temps have been good, but it's never a bad idea to bring along a thermometer just to be safe. Observed hatches are Midges, BWO's, Caddis, Yellow Sallys and PMDs.

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For dries, use a Chubby Chernobyl, Angee's Knobler, Fool's Gold Sally, AR's Adult PMD, Hi Viz Quill Midge, No See Um Hi Viz BWO, Peacock Cluster, Ms Tickle Cripple in BWO and PMD, Griffith's Gnat, AR's BWO Adult and Emerger, All Season Caddis, Superman Caddis, and a Hot Mess Midge.

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For sub-surface, use a Juju Baetis, RS-2, Puparazi, Zebra Midge, Tailwater Sow Bug, AR's Spanish Bullet, Tung Split Case PMD, TB Bender PMD, Lil Bit, Tung Stud, My Gal Sal, Juggarate Chocolate Baetis, Tung Poudre Pupa and a Hogan S&M Nymph.

Guide Rating

4/5

Weather Experienced

- Temperature: Upper 70's

- Wind Conditions: WIndy

- Precipitation: None

Water Observations

- Water Temperature: Lower 60's

- Flow Level: 133 CFS

- Water Clarity: Light stain

About Big Thompson River Fly Fishing

Starting as a mere trickle on the east side of the Continental Divide, inside Rocky Mountain National Park, the Big Thompson flows from Forest Canyon Pass near the top of Trail Ridge Road through Forest Canyon. As small drainages offer additional snowmelt, the Big Thompson picks up volume, turning into one of Colorado’s finest streams.

The Big Thompson becomes fishable at Moraine Park in Rocky Mountain National Park, about six miles downstream of its headwaters. It’s there at Moraine Park, where the river splits into numerous braids and channels, that fisherman encounter the river’s first public access. Trails leading up and down the river from that point will lead you to great flyfishing experiences.

Moraine is a wide-open area, but the Big Thompson’s banks are lined with willows. It’s typical small stream conditions, and the river is filled with, you guessed it, brook, brown, and cutthroat trout in the 6- to 12-inch range. They’ll readily take a variety of general attractor flies.