Tornado Season is coming...

Tornado season it coming. Throughout the South tornadoes start hitting frequently in about March. Further North it's a little later.

This is important to consider if you want to build yourself a storm shelter. For me it was almost exactly two months from when we excavated to when we removed the supports holding up the poured concrete roof. Making and mounting the door took a few more days.
If you want a shelter for the coming season it's time to start making things happen. There's not a lot of time to waste.   
Also, building a smaller shelter can speed up some aspects of construction. The spreadsheet included with the video can help you explore the cost, material requirements, weight, etc of any size shelter you want (but my roof design is only good to 12' wide - an engineer could design wider, though).

diy storm shelter design calculations