Daily River Forecast

Bighorn River

Fort Smith, Montana

Bighorn River | Fort Smith, Montana | Updated September 13, 2026 | Station: Bighorn River below Yellowtail Afterbay Dam near St. Xavier, MT

  • Maintain a drag-free drift near the bottom structure where trout are holding in steady tailwater flows.
  • Use Indicator Nymphing.
  • Favor Weighted beadhead nymphs and small soft hackles.
What's active
Fish this
Scuds, size 16-18, Morning (6:00 AM–10:00 AM)
Olive Scud, size 16-18, dry; Tan Scud, size 16-18, dry; Ray Charles, size 16-18, dry
Sowbugs, size 16-18, Morning (6:00 AM–10:00 AM)
Grey Ray Charles, size 16-18, dry; Tailwater Sowbug, size 16-18, dry; Czech Sowbug, size 16-18, dry
BWOs, size 18-20, Morning (6:00 AM–10:00 AM)
BWO Sparkle Dun, size 18-20, dry; Pheasant Tail, size 18-20, dry; RS2, size 18-20, dry
Midges, size 20-22, Variable
No matching fly supplied
Caddis, size 16-18, Variable
No matching fly supplied
Flow1,840 cfs and steady
Water TempUnavailable
WeatherOvercast
Rating9/10 · Excellent

The Bighorn River below Yellowtail Dam offers stable tailwater conditions with overcast morning skies, favoring consistent subsurface feeding on scuds, sowbugs, and baetis nymphs.

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.