Looks like today will be clouded but without rain
So it's going to be dusty, superdry cobblestones, probably comparable to how the sections were when many GC teams did their reconnaissance (maybe a bit more dusty today).
Therefore can't see the cobblestone sections be the factor of people dropping today.
It will be a very high-paced race with - most likely - more than 1 crash, because of the crazy tempo the GC teams (especially Tinkof, Sky and BMC) will uphold.
Pretty sure in these conditions the winner doesn't necessarily will have to be a cobble stone specialist. Don't think that we will need to expect people like e.g. Van Marcke or Stybar for the win today... if they manage to stay in the front and avoid crashes this might even be for the sprinters that you normally don't really see/expect at the end of PR (Cav, Greipel, Kristoff).
Gotta give Van Avermaet, Boom and Sagan some extra chances today, since they belong to the "strong" teams and will therefore more easily stay in the front. You would expect that Degenkolb gets free reign today, however with the - so far - pretty good riding by Barguil (and the abandon by Dumoulin), not completely sure if they aren't going to ask Degenkolb to try to look around for Barguil and keep him at his side. I am also wondering if EQS (Stybar, Trentin, Vermote and Kwiatkowski) will actually try to guide/focus on Tony Martin to get him that extra second he needs towards Froome.