I am still trying to guess what happened. My suspicion is that the rear steerable bogie cut the corner too tightly; the embankment gave way; the bogie went down, causing the load to roll, in turn rolling the prime mover. Why then are the white side posts still upright? Are they sufficiently flexible to spring back? Did the load roll above them?
I certainly don't post every truck collision/fire/accident, but this one is highly unusual.
It also reminds me of the trucking up the purpose-built Snowy Mountains road of oversize equipment, barely clearing the cuttings, with the road operating with one-way traffic.
There are lots of youtube videos of trucking oversize loads in tricky situations. Recent ones including trucking out the fuselage of the plane which went into Hudson River (New York, New York), and the trucking in of a Constellation fuselage to be part of the TWA hotel at New York JFK airport.
Those white posts are designed to lay down and then stand back up. Initially it was introduced for the mowing of the side of the roads. No need to mow around the old timber post, just drive over these ones and all is good. Trouble was that after a while they did not stand up as designed as the flexible rubber started to fracture.
I wonder if the damage to the blade could be repaired or if it was a wright off.