Explain "Roaring Cries" To Me

I'm using warcries and am seeing this notable on the tree called "Roaring Cries" that makes warcries have a minimum of 10 power.

Does that mean if i use Infernal Cry on 1 enemy, that this enemy will count to 10 power instantly?
Does this also work if there are no enemies hit by the warcry?

Yes, that's how it works.