Kind of a long shot, but...
Judging by the picture it reminds me a lot of an incident I had two years ago in what could've easily ended the same: training flight in a 44, intended to set down in a grassy patch at the end of a runway. After a quick look around on the ground the area seemed to be reasonably flat but we overlooked a furrow that was hidden under grass. Of course we hit exactly this furrow on touchdown
The helicopter immediately got into a fast, violent, diagonal rocking motion about the furrow as a pivot point (comparable to Ground Resonance) and we managed to pick it up just in time with no clue what the heck had just happened - luckily there was no damage except for a little dent in the aft cowling / a little hole punched into it by the skid fairing.
Looking at the picture I could very well imagine that the same thing might have happened here: snow covered field, furrow not discernible, hit it a tad too hard and slide across, violent rocking motion starts - machine disassembles itself in a matter of seconds.
Indicators would be
- the helicopter standing at an awkward angle across the furrow
- skids not damaged / spread
- what seems to be a hole that's punched into the aft cowling by the skid fairing
- the long crease in the aft cowling
- the crumbled vertical stabilizer and drooped tailcone
- the mast obviously severely shaken from the event
- gearbox ripped apart by severe vibrations (see oil leak on LH fuselage)
Only thing that puzzles me in this scenario is that the blades did not contact the tailboom.
