Looks like the tank itself is damaged like several tanks in Texas, last week. You can attempt to fix the (pipe) tank and add a recirculator to run water effectively. Or get a replacement and better insulate it, like many people did after getting this issue.
I am assuming you have only one water tank. The problem you mentioned happens when you have more than one heater tank and the expansion tank for recirculating fails. In Texas, many families who put waterless tank had their heaters damaged when pipes froze last week. Please get opinions from 2...