The tip of the boom was left about 2 feet too high, it hit the lower "skirt". The boom rotated back as it went through and popped out the top of the bridge, but not quick enough for the rest of the machine to sit still. You can see where the whole thing swung up and the cab contacted the bottom side of the bridge. The trailer instantly broke away from the truck. That'* why it'* still underneath the backhoe.
Wow that is impressive. Imagine driving along and seeing that mast poking up and cutting across the road in front of you
Yes, I can see how that occurred as Wikoff has outlined.
I never would have thought it would have caused so much damage and is a testament to the strength of those crane booms....not even bent, visibly.