There appears to be some disagreement with the comments that this collision occurred in a thermal. Found the following comments online regarding this accident.

From Fun Junkie:

This was a tragic ACCIDENT, nothing more. Having reviewed the gps logs of each gliders flight path and the video of the collision, there are two things that need to be cleared up.

First, neither glider was in a thermal so the discussions about that are pointless.

Second, neither glider was "show boating" or doing anything unsafe at the time of the collision, or prior to it.

They were simply flying in an area they knew very well and have flown hundreds of times before. On this particular flight they happened to be flying in the same geographical area but approaching from opposite directions. Both gliders were in essentially level flight and at the same altitude. For whatever reason... they simply did not see each other in sufficient time to avoid a collision. Gliders approaching each other at the same altitude are very difficult to see and close on each other very quickly. As a friend and fellow pilot of both Keith and Ray, I will miss them dearly and offer my sincerest condolences to their families and friends. This was simply a very tragic accident between two pilots who took flying safety very seriously.

End of comments

Amazing how often the facts of the case take a long time to become clear. The idea that they were not in a thermal makes more sense to me.

Walt