Self-built Tornado Shelter, how to.......

Most of us have seen, on the news, or in person, the devestation that recent tornadoes have done in the midwest states. It's terrible.

So far, we have had tornadoes (small ones) do damage within 10 miles of home, 2 times this spring.

We live on a rural 1 acre lot, and could dig our own tornado shelter.

I've been looking at those steel waste dumpsters, which are not all that big, but there's just the 2 of us now.
And wondering what would be wrong with digging down and putting one just below ground level. Some of them even have a steel door.

Yeah, I know it's probably not FEMA approved....... but it's got to be safer than any room in my cabin style, open design, 800 sq. ft. slab house. I think a tornado would just wipe the slab clean, the way my house is designed. I'm also thinking 'cheap' here. We can't really afford a 'real' one, so just trying to figure out something.

Has anyone here made any type of homemade tornado shelter ? We are mostly interested in something below ground, or even hilled-in, rather than a safe room style. Our house has no place for the safe room type. It would have to be something else.

I'd like to hear ideas, and get some links if anyone knows any. Thanks all, be safe !