SSD,
I have many years of gliding and towing in the lee of the Canadian Rockies. The rotor occurs downwind of the upgoing air, underneath the "crest" of the wave, where as you said, there is shear between the wave airmass and the underlying air. The rotor is often marked by very ragged, wispy, dark clouds, that are visibly rotating.
The rotor can be extremely rough and quite violent. A very experienced tow-pilot friend of mine used to say "The rotor's not rough until you get rolled inverted!"
Typically, the rotor only occurs at or below the ridge level of the mountain range that is generating it. The largest gust "jolts" I have experienced while flying commercially in the western US and Canada, have been while climbing or descending through the altitude of adjacent mountain ridge lines, on windy days. Based on my "Chipmunk calibrated posterior", I estimate some of them to have been ~2G. Quite scary for non-pilot passengers.
A typical wave-tow consists of flying up-wind through the rotor until you reach the upwind side and then turning to track parallel to the mountain front and climb in the disorganized lift until the air becomes magically smooth. At this point, the glider releases and by the time the towplane has done a 180, the glider is a 1000' or more higher.
The laminar flow in a wave is uncanny. Often the only indication in a glider that you are moving, is the altimeter winding upwards.
PS I've never towed into a wave associated with isolated peaks, but I've seen the so-called "UFO" lenticulars that form downwind of the Cascade volcanoes, like Mt. Rainier. I would image the rotor associated with those waves might be even more violent, because of air coming around the mountain, as well as over it.
Here is a nice time-lapse video of cap clouds and lenticulars at Fuji, although the labelling at the beginning is wrong. What is labelled as "Rotor Cloud" is the stack of lenticulars, marking the laminar wave. The actual rotor can be seen as fast moving wispy clouds, just above the foreground ridgeline. There is a good example at 0:25:
I expect the day of the BOAC accident would have been a "blue wave day", where there was not enough moisture in the airmass to form clouds.
Last edited by India Four Two; 10th Mar 2016 at 11:21.