Tornado Alley (PROG)

[woofer]

That's a fascinating video but I couldn't find more on the subject. What I'd like to know though, is why it took 3 years of digging. I don't see where 3 years of digging was necessary unless they're referring to digging in other places as well. Was the church filled with dirt? And they didn't want to disturb any of the structure while digging?

Now, after three years of digging, the secret has been revealed.