Waterlands
River Intelligence · Entomology

Read the Water. Match the Hatch.

Every river has an entomological fingerprint — the bugs it grows, when they hatch, and how trout eat them. Learn the bugs, cross-reference live flows, and fill your box before you go.

Hatching NowPale Morning DunGreen DrakeTricoSulphurSmall Western Red QuillFlavGray DrakeCallibaetisSpotted SedgeGolden StoneYellow SallyBrown DrakePink LadyTerrestrialsScuds & Sowbugs
EncyclopediaHatch CalendarRiver FingerprintsMatch the HatchBug School
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Yellowstone River
Paradise Valley · MT
The longest undammed river in the lower 48. A moody freestone with a huge stonefly biomass, salmonflies in early July, and hopper water for miles.
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CFS
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Water Temp
The Fingerprint
Classic big freestone: stonefly and caddis biomass, late runoff compresses the dry-fly season into an intense July-October window.
Fly Box for Right Now
Elk Hair Caddis #14-16
Spotted Sedge · Adult
$2.95
CDC Caddis #16
Spotted Sedge · Adult
$3.25
Parachute PMD #16-18
Pale Morning Dun · Dun
$3.25
Comparadun PMD #16
Pale Morning Dun · Dun
$3.15
Dave’s Hopper #8-12
Terrestrials · Adult
$3.50
Chernobyl Ant #8-12
Terrestrials · Adult
$3.50
Hatch Chart — Yellowstone River
River-specific intensity: this water, these bugs. Click a bug for its full profile. Likelihood is seasonal — this gauge supplies no live factors.
≋ Waterlands · Hatch data blends USGS gauges, NOAA temps & regional emergence records
USGS Real-time Data · Free to Start · No Credit Card