Fort Smith, Montana

Bighorn River Hatch Report

Updated Apr 24, 2026, 7:36 AM MDT

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.

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
Today's Read

Bighorn River is keyed to the bugs that are active in the current light and water conditions. These are the insects that matter right now and the windows when they matter most.

Current Hatch Report
  • 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
Flies To Match The Hatch
  • 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
How Fish Respond To This Hatch
  • 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.
  • Use a shallow indicator rig unless releases are up. Most fish eat better on short, controlled drifts than on a deep bobber setup.