Doublet - I think I confused you. The wave I'm talking about is right off a Shelley town exit on I-15, north of Blackfoot and south of Idaho Falls. It MIGHT be called the Woodville wave.
It's likely not well known because it's a shelf wave, only comes in at high flows - and that section of river is pretty much class I. In 1999 (and probably 97 and 9
the wave came in great around 18K-20K and it was amazing - friendly, best eddy service I've ever seen, easy to get onto, etc.
I agree, the upstream reservoirs filling up (Palisades, others) will have a lot to do with whether or not it runs. The year(s) it ran were also the years the bridge washed out on on I-15, and the one upstream by Heise.