I have seen something like this one time (yes in the South) it was from a roof leak at school. The block filled up the day before a 19 deg. night and no heat in the building. Wall had to be removed due to broken block. I was called out to dry out the blocks, I asked why? They had not seen all the cracks.
Yes, there was a lot more than several hundred gallons
The rest of it went inside and on the other side of the flat roof.
It was about a 7000 sf structure with 3000 sf of water migration on the lower level
The upper was about 2000 sf with about 1000 sf of water migration.
It was about 48 hrs old.