Madison River · hatch chart
Fishable all twelve months; the season is defined by whether the salmonfly hatch has started and whether Hebgen is spilling
By month
JanFebMarAprMayJunJulAugSepOctNovDec
| Month | Insect | Stage | Size | Time | Intensity |
|---|---|---|---|---|---|
| Mar | Midges (Chironomidae) | Pupa | #18-22 | 11:00-15:00 | |
| Apr | Blue-Winged Olive (Baetis) | Emerger and dun | #18-20 | 12:00-16:00 | |
| May | March Brown (Rhithrogena) | Dun | #14 | 13:00-16:00 | |
| Jun | Spotted Sedge (Hydropsyche) | Adult, evening egg-lay | #14-16 | 18:00-dark | |
| Jul | Golden Stone (Perlidae) | Adult | #10-12 | All day | |
| Aug | White Miller (Ephoron) | Spinner fall | #12-14 | 21:00-23:30 | |
| Sep | Trico (Tricorythodes) | Spinner fall | #20-24 | 08:00-11:00 | |
| Oct | Blue-Winged Olive (Baetis) | Dun and spinner | #20 | 13:00-16:30 |
Flow and visibility
Hebgen Dam releases are posted daily by the US Bureau of Reclamation and are the single most useful number in this valley. A rise of more than about 500 cfs overnight turns the wade stretch into a wading-hazard zone and pushes fish to the banks; a stable or falling flow makes the same water easy. Water clears within 24 hours of a release because the dam releases from the bottom of the reservoir.
The insect plate
