They have to find a block for difficulty to adjust down.   If there are less than a block every two hours after that block, difficulty will drop again.   and so on.   until you get to a managable point.
then some miners will hop over and the see saw begins between the two chains.   Instead of the old pool hopping, maybe we will see chain hopping by miners.
Maybe Organ will come out from walkabout and actual make some money putting together chain hopping strategies.

Or the new branch just dies.   who really knows right now.
the only thing for sure is that a lot of exchanges stole a lot of BCH from accounts.