Desert 185,
Thanks for your reply. I suspected that might be the case.
In the Front Ranges of the Canadian Rockies where I flew, the peaks are below 9000', so it is feasible to climb above the rotor.
Also, we don't have another set of mountains downwind to complicate the wind patterns.
The elevation difference from the valley to the peaks is only 5000', so altogether a much smaller scale than the Sierra - Owens Valley situation. In spite of that, we regularly get waves to over 40,000', particularly in the Fall.