First let me say I don’t consider myself a expert. However I have studied on the subject and would like put forth what I have gleaned from my research.
1 Weather patterns shift. When I was a kid in Louisiana you never heard of a tornado’s there. Now they are commonplace.
2 Stick built houses (2 by 4 construction) and trailers cannot stand up to even a weak twister.
3 Even in a weak storm the flying debris is deadly.
I also found out that a large numbers of deaths were caused by this lethal debris as people were waiting for the last second to get into their shelter/safe place.
So why were people waiting so long to get into their shelter or safe place? The answer is simple, they are not comfortable places to be.
Again why is that so? There are several contribution factors to this. Most are smallish. 8’x10′ is considered large for a shelter. They are not (usually) maintained well. The outside ones are usually dank and have bugs etc. because of this lack of maintenance.
The inside ones are (usually) considered a waste of space, are cramped and lack ventilation.
In my opinion the #1 reason is the lack of information/contact with the outside world! Prior to going into the shelter you are glued to the television watching the progress of the storm. This is especially true at night.
Think about it, prior to going into your shelter, you have television, radio, weather radio, telephone, cell phone, computer and Internet. Also you have things like HVAC , water, bathroom etc., IE comfort. When you enter (most) shelters all of that is gone.
After the first time you have sat in your man made cave under the stress of a deadly storm coming and nothing happens, Your mind makes it hard to repeat the process until the last moment.
I understand the cost of a shelter. (That is the reason most are smallish.) But with a little pre-planning you can turn the uncomfortable to bearable.
For those dealing with an preexisting structure a outside shelter will probably be the least expensive.
For the outside shelter:
Run in a couple antenna wires for a small television and or a radio. Think about a hard line telephone or cell phone repeater antenna. Install a solar powered shop light, and/or vent fan. Add a bench or a couple folding chairs and that should work. Just make it work for you.
Note: For those that live in areas with high water tables, there are several integral (one piece) shelters that are made of steel or fiberglass that will greatly reduce the water issue.
For the inside safe room it’s usually less expensive to deal with this during construction. A lot of people put it under the garage since you have to have a slab floor for that already.
I took the approach of turning one of the basement bedrooms into a safe room. I was able to take advantage of three existing concrete walls, and only had to add one concrete wall and a slab roof. This gave me a nice sized bedroom and full bath under a “hard” roof. I had it preplanned for HVAC, television and radio antenna wires, hard line telephone. After construction I added emergency lighting.
This may not be the best approach for some but it worked for me.
Bottom line make your shelter/safe room as comfortable as you can so that you and your family won’t mind going in there. Kids especially will be nervous. You may think about pre positioning coloring books or something to take their mind off of what is actually going on. The stress of the weather event itself will be bad enough. You family, especially the kids, don’t need the added stress of being in a “scary” place. – Wolfgang