I don't know which angles I have, but I think the pics were pretty high rez, so I might be able to blow something up for you. (photographically speaking, of course)

of the forefemora could provide additional support for the family/genus ID, and close-up views of the last few abdominal segments (dorsal for males and ventral for females) are always among the most helpful views for identifying adult stoneflies--though these are seldom available. However, even that might not allow confident identification beyond genus.

There are nearly 60 species of Isoperla in North America, and at least 12 are recorded in WA. A number of these are very similar in appearance, and a few can easily be confused for species in other families/genera (particularly some of the small perlids of Perlesta). Most of the Isoperla images in the guide that have been identified to species level were keyed from specimens "in hand" by Dr. Chandler. Eventually, that may allow other specimens to be matched to those, but that can also be a tricky proposition. (See my caution here, for example.)