Well, all I know is, that the ship was hit by a storm from the port quarter (= the sea was coming from the aft) and that some huge waves hit it very strong. I can imagine, that the ship begin to roll and in a bad moment it was hit by a wave while it was listing.
Obviously, it's pretty interesting to see how strong the twistlocks had been because most of the boxes are still on board. But in the port where these broken boxes were discharged I guess it wasn't an easy job to get them from board.
mfg blackbat