Blackfoot River Fishing Report, August 4, 2026
2026-08-04 (August 4, 2026)
Regional summary
August has settled over the four rivers with the particular hush of low water. Gauges are down across the board, hoot owl restrictions (no fishing from 2:00 p.m. to midnight) now cover every named stretch from the Blackfoot to Upper Rock Creek, and fish are holding wherever they can find oxygen. The pattern repeats on all four rivers this week: fish early, carry a thermometer, and treat the 6:00 to 10:00 a.m. window (the read from Lightweight Fly Shop in Stevensville) as the day's real opportunity.
At a glance: Bonner gauge near 858 cfs and falling | 69°F at midday | dropping and clear | Grizzly Hackle rating: 3/5 | Best window (Lightweight Fly Shop): 6:00-10:00 a.m. | Hoot owl from Cedar Meadow FAS to the Clark Fork confluence (no fishing 2 p.m. to midnight) | Floating closed Weigh Station to I-90 through October 31
Float hazard: an obstruction below Harry Morgan on the North Fork of the Blackfoot has caused several boat accidents. Walk the boat around it, or put in at River Junction instead.
The Blackfoot has slipped fully into its August character. The Bonner gauge sits near 858 cfs, off from last week's reading, and Blackfoot River Outfitters clocks the midday water temperature at 69 degrees under clear, dropping conditions. Hoot owl restrictions now run from Cedar Meadow Fishing Access Site to the confluence with the Clark Fork (no fishing 2:00 p.m. to midnight), and the float from Weigh Station downstream to the Interstate 90 crossing stays closed through October 31 for the railway bridge project. Boats can still take out at Weigh Station; they cannot put in there. Smoke has settled into the valley along with the heat, with highs near 95 forecast for Saturday before a Sunday cooldown into the 70s.
Best techniques
- Dry dropper rig covers the water best right now: a size 8 or 10 Chubby Chernobyl or hopper up top, with a Duracell, Prince Nymph, Frenchie, or Yellow Spot Pheasant Tail trailing two to three feet below
- Spruce moth activity is building through the shaded timber, worth a standalone dry once fish key on it
- Streamer fishing pays off in the deep plunge pools and boulder seams when the top water goes quiet
Hatches
Late season PMD spinners and Tricos still show on the morning slicks and foam lines, Yellow Sallies are fading, and spruce moths are waking up in timbered stretches. Terrestrials (hoppers, ants, and beetles) are becoming the day's real currency as the summer bug cycle turns over.
The Fly Box
Nymphs: Pat's Rubber Legs, Zirdle, Frenchie, Duracell, Pheasant Tail Nymph, Prince Nymph
Emergers: Flash Cripple
Dries: Chubby Chernobyl, Water Walker, Purple Haze, Film Critic, Carnage Drake, Billy's Butterfly
Streamers: Sparkle Minnow, Goldie, Swim Coach, Sir Sticks-a-Lot
Outlook. Expect this pattern to hold through the coming week, cool mornings, hot smoky afternoons, and a narrowing productive window as the month wears on. Kingfisher Fly Shop and Grizzly Hackle both track the day-to-day shift in this bug cycle closer than any report can, so a call or a stop in before a Blackfoot morning is worth the five minutes.
Sources and Thanks
| Shop | Report date | Coverage |
|---|---|---|
| Blackfoot River Outfitters | July 31, 2026 | All four rivers |
| Kingfisher Fly Shop | August 3, 2026 | All four rivers |
| Grizzly Hackle | July 29, 2026 | All four rivers |
| The Missoulian Angler | July 16, 2026 | All four rivers, background |
| Lightweight Fly Shop | August 2, 2026 | All four rivers |
