Very tragic RIP . Unsubstantiated chatter on another internet forum indicated early thoughts were of mast bumping. In any case, from the NTSB preliminary report:
The helicopter came to rest in hilly desert terrain. The debris field was about 750 yards long and 150 yards wide. One of the first pieces identified was the outboard 5 feet of a main rotor blade afterbody that had separated from the leading edge spar. The left side of the helicopter was more fragmented than the right, and left side cabin pieces and instruments were distributed throughout the early part of the debris field. The tail boom was about midway into the debris field. The left side/nose cabin was in the same approximate part of the debris field with a straight separation line across one side. The cabin came to rest inverted about 600 yards into the debris field, and was destroyed by a postcrash fire. The engine remained attached to the cabin. The remaining piece of main rotor blade was about the same distance into the debris field, but 85 yards left of the debris path centerline. The transmission, mast, and second main rotor blade separated as a unit, and were about 100 yards past the cabin area in the direction of the centerline of the debris field.