This last bit is important. Even if the ravine were not exposed on the fatal night, any snow pack covering the stream would have been a trap that collapsed if anyone had stepped onto it.
It's quite possible the rocks were bare. In that case, we have to focus on how high of a snowdrift could have accumulated on the slope, heightening it as a result. The worst case scenario is exposed rocks AND the slope still somehow elevated by a snowdrift. The fact the bodies were discovered under over three meters of snow suggests snow could accumulate in the ravine quite nicely (and from the pics, there is seemingly no reason not to) and/or once the snowdrift on the slope reached a certain level, it would collapse down in the ravine.
Again, it's possible the foursome hit the most hostile of all possible scenarios, i.e. the rocks exposed, the snowdrift on the slope reaching its maximum high before an inevitable collapse.
I'm confident Dubinina's ribcage injuries occurred in the ravine. The penetration of her heart by a broken rib was a fatal injury that would have meant instantaneous incapacitation and death within minutes. She's the one who most obviously came from the cedar / campfire site circa 70 - 75 meters away. If she'd already suffered the ribcage blow-out there's almost no chance she could have made it to the den scene.
Let me start from another end.
I've just come across this pair of pics illustrating the view of the tent from the point of the cedar and vice versa (sorry if these have already been posted):
And now the opposite direction:
Now, it's likely that whoever climbed the cedar and cleared the branches in direction to the tent (autopsy hints at Doroshenko) was trying to look at the situation around the tent, as the slope obviously does allow to look towards the tent point.
I figure this climb must have occurred shortly after descending to the cedar area. This is because no-one would be able to climb up a tree after losing sensation in their hands/fingers and feet (which is one of the early symptoms of hypothermia). We also know that Yuris were most likely the first to die, presumably within an hour / hour and a half after the tent departure.
This leads me to believe they thought the situation around the tent could be visible from a distance. That hints at a light / a possibility of a light / possibility of a light approaching / descending.
It also suggests that soon after the descent, they realized their own situation was highly dangerous and it would better be changed as soon as possible.
Now if they realized their situation was so bad so quickly, why not return? It seems to me they decided to stay because the inspection of the tent area from the cedar had not assured them it was safe to go back.
I tried to imagine some of them could have descended later. But... If some of them could have descended later, why did Yuri's leave the tent so underdressed and unshod?
Then I figured perhaps they were trying to localize the flashlight dumped about 400 meters down the slope in attempt to navigate the part of the group that wanted to return to the tent. But purposely dumping a working flashlight as a beacon so few meters down the slope and then heading on into a pitch black night does not look like a plausible strategy.
Any way I look at it, it seems likely someone rather than something scared them away from the tent. I would also love to see the return track compared with the direction of their descent, or at least where their descent tracks last pointed before they disappeared.
I realize that if the return track proves to be a notable deviation from the probable descent line, it can be argued as a proof of disorientation rather than a means to avoid someone who could have run after them. But if their heads actually pointed towards the tent despite taking a different route back, it would hint at a purpose rather than accident.
Also, Semyon was wearing Ludya's jacket and hat. What do we make of it?