#Rules as Written - No
Rules as Written - No
As per the Cover rules, any attack at a creature that you aren't able to see, due to an obstacle completely obscuring the enemy, is treated as if they had Full Cover.
A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.
In the case of your example, you won't be able to target or hit any enemy with the thrown axe.
Think of this as a real world example of throwing a ball over a fence at a friend who is trying not to be hit. Any momentum in the throw will be lost on the way up, and you wouldn't know where behind the fence your friend was standing.