As of today, in season, building toward peak (~June 20). Earth Exhibit tracks the live conditions and flags it the moment it is on.
Each late spring, large stonefly nymphs (Pteronarcys californica, known as salmonflies) emerge from the Madison River, molt to winged adults and crawl onto rocks and vegetation.
The multi-day hatch draws anglers and naturalists because of the sheer numbers and its strong influence on river food webs and fly-fishing patterns.
Where to see it
A taste of where to see it. The full map, exact coordinates and the best timing for each spot live in the app.
| Viewing spots |
|---|
| Ennis Bridge / Town Reach |
| Lyons Bridge / Lower Madison Access |
| + 1 more spot, with exact coordinates and timing, in the app → |
This is the short version
This page shows a taste. The app has the full list of where to see this, the exact timing, and live conditions for 1,000+ natural phenomena worldwide, so you know the moment one is genuinely worth the trip.