The stonefly hatch (also known as the salmonfly hatch) begins early in May on the Lower Deschutes River and provides nearly a month long opportunity to target the river's wild redsides with huge dry flies. This can be a busy time on the Deschutes and for good reason. Stonefly fishing kicks ass.
The stonefly hatch is a term we use for a mix of three distinct overlapping stonefly hatches. Giant salmonflies, golden stoneflies, and yellow sallies. These bugs hatch in dense proportions but vary from one part of the river to another. Having patterns that imitate all three species is important. Don't have your heart set on salmonflies and consider it the stonefly hatch rather than the salmonfly hatch.
Knowing what the trout are seeing and what it takes for them to key in is paramount during the earliest phases of the hatch. Banks with direct morning sunlight will undoubtedly attract the most salmonlfies, who seek warmth during cool weather typical of early May. The trout will key in a little sooner along those banks than elsewhere in the river.
During the later stages of the hatch finding trout that are keyed in is easy. Finding a trout that hasn't been well educated is another matter. Playing your cards right is everything, and might include diving into the densest brush, fishing lower in the river with smaller flies, or using that deadly extra sparse patterns you've been holding out on all season. Anglers tend to get very focused on fishing the banks during the salmonfly hatch, and justifiably. Late in the hatch trout know exactly what a stonefly is, even if they aren't holding on the bank. A cast or two into more open water away from shore is a good idea, especially in the riffles.
Somewhere in the middle part of the hatch, under the right weather and water conditions, we hope to find salmonflies and golden stones dripping off the grass and tree limbs like honey into the waiting jaws of big hungry trout. This is what the Deschutes stonefly hatch is famous for.