@akaSylvia
having a hard time getting my head around the type of ground impact that would leave this sort of mess
You would need more information to get a good answer of course... But one aspect that we could keep in mind is that it is a high wing with underslung engines. So the impact dynamics can be quite different.
One scenario might be that the final segment of the flight path was under a shallow angle and at some speed. Which might explain the impact 'channels' in the snow. The entry being such that the wing-engines combination detaches from the top of the fuselage. Which might explain the very unusual and high 'roll over' trajectory of 'long flames' on one of the videos. This detachment both rupturing the fuel tanks and destroying the structural integrity of the fuselage. Which might help explain a combination of fragmentation and deformation that could follow that ...
Even within such a single scenario there are multiple possible sub-options. Based on for example engine thrust at impact, impact angle, and impact speed.
If you look at the long flames, and assume we see the trajectory from the side, it might suggest that the planes was wings-level on impact.
The snow is at least knee deep and can hide quite a lot of information if you have to go by photos only.