Drawing a blank: what are underground shelters called?

I think storm cellar is an aceptable term.

I agree but it’s not the term I’m looking for.

I’ve always heard storm cellar, too. Storm shelter?

Maybe bunker? Basement?

I think the book just called it a cellar. We Middle-Earth types are more likely to call the hole under the house a basement; I’m sure that there’s a distinction.

Maybe it’s tornado shelter. Or as @augustlan suggested, storm cellar.

Cyclone cellar?

Root cellar ( root crops storage like potatoes and carrots?)

Bomb shelter?

“Aunt Em dropped her work and came to the door. One glance told her of the danger close at hand. “Quick Dorothy!” she screamed. “Run for the cellar!”
L. Frank Baum

It may depend on where you live. I believe they are, indeed, called storm cellars.

Fallout shelter?

Storm cellar is what I was looking for but wow; what funny replies! And so many! lol