Only two species of Okanagana occur in this area (see www.cicadamania.com/downloads/diversity-05-00166.pdf): O. canadensis and O. rimosa. Dorsal thoracic spots and wing veins are yellowish in the former (as in this one), but reddish in the latter. In addition, O. canadensis has more "hunched" mesonotum and lacks red borders to abdominal tergites of O. rimosa.
Photographed in a portable lightbox at the Carpenter Mtn fire lookout, HJ Andrews Forest, Willamette National Forest, Oregon