Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
Late May is an odd time to hunt for rainbow trout along Alaska's road system. The adult salmon aren't in yet, most of the smolts aren't really running yet either, and the rainbows are in limbo between their mysterious headwater spawning locations and the places they enjoy salmon smolt and egg buffets later in the summer.
Last year, when the rivers were atypically low due to a light snowpack, I fished three miles of a favorite creek and moved only three rainbows, all of monstrous size. This year, greater snowmelt had the creek swollen beyond long-distance wadeability, so a friend and I explored some absurdly off-the-beaten-path access points, the kind where it takes an hour to reach a piece of water in which nobody else has set foot for years.
On this new water, I caught one 19" female and briefly saw a nice male rocketing downstream post-spawn. Mostly, though, the scenic new reaches were a bust from a catching standpoint. At the end of the day, I bashed through half a mile of alders and devil's club (R.I.P. my waders, 2019-2020) to reach a known hotspot and caught six fish, mostly 18-21", before a storm rolled in and chased me back to the car.