Those are some pretty large scatters if that's what they are. I would be happy if that was how they are done in game-play but I am not sure that we will have this based on current footage and dev comments.
@Snark I hope these features are extremely large scatters as you guess. If not, I would be a little disappointed as I am not sure how they would have the overhangs shown in the trailer. Not a deal breaker, and I am still very excited about this game. This might be a good question for the developers.
I don't trust that just because the terrain appears a certain way in the trailer it will be the same in game. For example the devs have been noncommittal on the question of clouds even though those were featured in the trailer.