The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
Water temperature: Most sources say 50-55 °F, though Fred Arbona reports 55-65 °F
Time of day: Late afternoon to evening; or, on cold evenings, delayed until 7-11:00 a.m. the next day
Habitat: Riffles and runs
Current speed: Everything except extremely fast; they move to slower water near emergence time.
Substrate: Gravel, small boulders, vegetation. Swift gravelly runs are especially favored.
Environmental tolerance: Among the least tolerant species in the family. They require moderate temperatures, neither too hot nor spring-fresh cold, and they cannot tolerate pollution.