Here's what I sent to Jim in response to his message above:

Both accidents seem to fit very well with what I call "99.9% safe
maneuvers" -- things we can do without event many, many times, which
then build up a confidence in our skill. But that's really complacency
masquerading as confidence. The danger is that a combination of events
then come together at just the wrong time, turning an otherwise normal
and "safe" maneuver into a fatal one. "Unusual" turbulence, wind, etc.
is a good indicator of the one-chance-in-a-thousand that can kill even
experienced pilots like Geoff or Steve. Unusual isn't the same as
impossible.

I assume you've seen my PASCO talk on this subject, but if not it's at

http://www-ee.stanford.edu/~hellman/...2007_talk.html

and an extension to an even worse 99.9% safe maneuver is at

http://nuclearrisk.org/soaring_article.php

Thanks again for your efforts to make these dangers better known
within our community.

Martin Hellman