Daily River Forecast

Bighorn River

Fort Smith, Montana

Updated for May 1, 2026

Top Summary

Stay with a precise nymph rig built around sowbugs, scuds, and small baetis, then be ready for pods of risers if the river gets a quiet overcast window. The Bighorn rewards small flies, fine tippet, and patient drifts through slick buckets.

Current Conditions
  • Flow: Tailwater flows can shift with dam releases, but trout usually stay in defined seams and shelves until flows move hard.
  • Water Temperature: Stable spring temperatures keep fish willing, but they still slide into softer edges when releases bump up.
  • Weather: Even modest cloud cover can turn on better olive activity here.
  • Overall Rating: 8/10
What's Happening Right Now

Bighorn trout are almost always feeding on something, but the river gets technical fast when bugs are small and the water is flat. Fish hold in soft buckets, inside shelves, and the gut of slower runs where sowbugs and baetis nymphs drift naturally. When BWOs show in decent numbers, pods can get selective and stay fixed on emergers just under the film.

What's Hatching
  • Blue-winged olives, size 18-20, midday under clouds
  • Midges, size 18-22, morning and slower evening slicks
  • Scuds and sowbugs, size 14-18, all day subsurface
Best Flies To Use
  • Ray Charles, size 16-18, nymph
  • Pink Scud, size 14-18, nymph
  • Zebra Midge, size 18-20, nymph
  • BWO Soft Hackle, size 18-20, emerger
  • CDC BWO, size 18-20, dry
  • Griffith's Gnat, size 18-20, dry
How To Fish It
  • Use a shallow indicator rig unless releases are up. Most fish eat better on short, controlled drifts than on a deep bobber setup.
  • Concentrate on slick shelves, tailouts, and the slow center seam of broad runs.
  • If fish start rising, switch to an emerger or cripple first. Trout here often prefer bugs in or just under the film.
About The Bighorn River

The Bighorn below Yellowtail Dam is one of the West's most productive tailwaters and a centerpiece of the Fort Smith fishery. Rich weed growth and stable cold water support dense trout populations and steady insect life for much of the year.

Brown and rainbow trout are the primary species. The river is best known for technical nymphing and selective dry-fly fishing when midges and BWOs are active.

Footer