I'm used to playing a Monk, where I'm defensive enough that the slams don't really bother me and have enough healing that I never really gave them any thought.
Now, I'm playing a Demon Hunter, and even though he telegraphs the slams with a big green meteor circle, I don't know how to avoid the impact. Even if his arm doesn't hit me, I'm still taking damage from the slams. Since I die in 2 hits to the slams, and my healing options are limited (potions have a cooldown and my damage output isn't exactly amazing while I'm running for my life to take advantage of Shadow Power), the best option is probably to avoid taking damage from them altogether.
Is there any pattern to his slams? How should I move to avoid them once he starts telegraphing that that's his plan?
To clarify, since there has been some confustion, this is not asking for Demon Hunter specific strategies. This is asking about Belial's attack pattern and how to predict and avoid it in general.