See Rule #14
A basement is underground, but from what I've read, it got flooded.
This town and the whole state is about as prepared as can be but you still only get a few minutes warning after one drops out of the sky.
No one wants to admit that we are that vulnerable, so there is always "fault finding"
The fact is that an EF5 tornado is just so freakishly powerful, safety can't be guaranteed. Not even in a storm cellar.