HA question

I have a question about the concept of high availability and DRS of vms.

Say I have 2 esxi servers and 2 storage boxes in a lab room.
In an event that something happens of one of the esxi boxes, HA would kick in and move the VMs to the other one, correct?

What if the power goes out in the building, could HA still work?

Would a possible solution be to move the storage box to a different location?
Or, put all the stuff in the cloud? If this is done, how would it work if the esxi box is down?

Thanks