Let's say you went out into your yard and dug a round hole deep enough to get your body into. You had a piece of board or plywood marked with orange or highly visible coloring with words stating you were in there. The board has a handle so that once you are in the hole, you can hold on and hold the board over the hole, pulling downwards against the suction.

Would this be a good idea? I mean say you are poor and can't really afford a shelter. You are not safe inside your home and need to be underground. I guess a spider hole would be the best idea. Anyone with a shovel should be able to at least dig down and dig a hole.

You need to be highly aware of where you will dig to avoid digging into water or underground power lines. You would probably have to at least dig down four or five feet, enough to crouch.

It might not even be "Legal" to do this, but heck with that.