I can't resist adding my speculation to everyone elses.
1. At decision , he sees the runway through the fog and realises he's off to the left of the centreline.
2. Decides not to go around again as he's done two GAs already and now can see the runway.
3.Attempts to regain the Centreline but a combination of the manoevers' difficulty (low vis, low level etc) , the aircrafts clunky roll response and his own state of mind result in the right wing hitting the ground.
4 Right wing section detaches. Left wing comes up and rolls the a/c inverted. It slides to a stop.
Total speculation on my part.