The Giant Salmonfly is one of the largest stoneflies in North America, with orange-red coloration on the abdomen and head that makes masses of emerging adults look like orange blizzards along western rivers. The annual hatch on rivers like the Madison is one of the most celebrated events in fly-fishing, with trout feeding intensively on the large emerging insects. Nymphs require 2–4 years in clean, cold streams.
Best time to see a Giant Salmonfly
The best time to see a Giant Salmonfly is April–June, when about 62% of U.S. sightings happen, based on 352 research-grade iNaturalist observations.
Not certain it is a Giant Salmonfly? What bug is this? walks through what to check first and the lookalikes that catch people out.
Recent Giant Salmonfly sightings near you
Live, research-grade observations from iNaturalist. Allow location to center the map on you.
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