Large flying ant patterns can be deadly in the west kootenays (Columbia, Salmo and Kootenay River). Difficult to find a well tied pattern though. Hoppers and deer hair caddis are also good go to patterns. If the fish aren't rising, hard to beat a bead head prince nymph under an indicator
Probably well worth your time to stop in at the local fly shops and ask what is hatching and buy a few patterns. Size and color patterns can vary a lot from stream to stream