Since the creation of ICF construction we in the United States have a choice that increases our ability to have a home or shelter that will survive a natural disaster. ICF or Insolated Concrete Form is polystyrene blocks that stack together to form walls. There is a cavity within the form into which poured concrete is allowed to cure. These structures can and have withstood hurricane force winds and tidal surges.
Now even if your home isn’t ICF there is no reason why you cannot build a “shop” in your back yard out of ICF. As long as the “Shop” has room for beds (Bunk beds in the case of a large family) the space can be air conditioned with a small window unit. (A gen-set can provide the power for the AC unit so long as you locate the get-set as far from the sleeping area as possible to avoid carbon monoxide poisoning).
Next to your “shop” you need to see if you can have a potable water well. If so the pump for this well needs to be able to be run off the same gen-set that drives the AC unit. The get set doesn’t have to be able to run both at once just one at the time. If you cannot have a well next to the “shop” then you will need a water tank of some kind. You need two gallons of water per person per day without showers so do the math and you will see why a well is the best choice.
I would have two rooms in this “shop” one exposed to the outside like a garage with the door open and the other fully enclosed.
The open room would have propane tanks (hundred pounders) this would drive the get-set and the electrical / gas camper refrigerator that was in the open room as well. Next to the refrigerator would be a propane grill for cooking and a propane water heater for sanitation. I would have a composting toilet in this open room with a curtain around it. (I would use this toilet only during emergencies.) I would have a three compartment sink attached to the wall in the open room drained to the sewer or house hold septic tank.
The inside room would have bunk beds or cots, a radio, a stand-alone gun safe bolted to the floor with the following in it: a shotgun, a hand gun, ammo for both, a satellite phone, a pay by the hour cell phone, first aid box (complete with any special meds anyone in the family needs). Shelves in the “shop” would have sleeping bags and river blankets, as well as tarps (for recovery of the household stuff if the structure is damaged). Can good could be stored on the shelves however, dries beans, rice, flour, instant potatoes, grits, and dry soup mix will keep longer and are cheaper to buy.
This simple “shop” would have walls that could stand fierce storms without yielding. It would keep a dry place for family despite what happens to the house. It has water, food storage, food prep and cooking, sanitation and climate control (Air Conditioning). A "shop" like this outside the home can protect the family from everything from flying debris to gun fire.