This discussion brings to mind an episode I had relatively early in my
soaring life. After licensing at Tehachepi in a 2-33, I went to
Crystal to
transition to glass in their Grob 103's. After being cleared to solo I
was flying along the San Gabriel's in an area that had been shown to
me.
The lift was sketchy and I was flying long passes through bands of
weak lift, not very close to the mountain, (I was and still am quite
cowardly). After hitting a strengthening patch of lift through two
passes, I had the brilliant idea to try circling. I made two circles
just like it was any other thermal I had flown and then, between
heartbeats, It all went to schist. I heard a loud bang and instantly i
was no longer flying. the car keys in my shirt pocket were pinned
against the canopy and all the gravel and dust on the floor was
floating in front of me. my angle of bank entering into this was
shallow and I think both wings hit at the same time. If it had been
one wing only, I would have been vertical or inverted faster than I
could have moved the controls to react.
Luckily I was pointed away from the mountain, and recovery was to
simply nose down and pull out. My own personal recovery took
considerably longer. There is no skill in the world that could tame
that kind of sharp edged shear while rock polishing, in my estimation.

Mark Jardini