my only input to add to this is I dont think the weather just rolled in. the road is wet, it appears that it had been like this for some amount of time. Much longer than it took them to fly into it suddenly, turn around and go back out.
Tally my opinion to the group that thinks these guys screwed up with poor planning over anything else and got away with avoiding an accident.
If its like any other mountainous area I have been in, I agree that weather can change quickly, but if you're experienced enough to follow a stone wall along a road, then you're experienced enough to know the weather patterns for that area. The weather changes or weather patterns are likely well known for this area for this time of year. There was no surprise. This was pushing limits for whatever reason.