"Or just register it with the fire dept and hope the government doesn't come knocking because you have a storm shelter."

LOL.

I wouldn't worry too much about it. Most fire/rescue departments are holding bake sales to keep the rescue equipment in tires.

They don't have a lot of spare time or energy left to run a 'shelter detection, reporting and exploitation division' to take full operational and strategic advantage of your converted closet or shed. Making it into a regional command and interrogation center where the war against the noble patriots and rebels is run from and innocent victims are are water-boarded for fun and profit.

Good effort!

Here in the D/FW area, I've gotten to see some structure damage analyses by Tim Marshall of Haag Engineering. Tim does a lot of tornado damage assessments for the National Weather Service. Here's his damage survey from the '99 Moore, OK Tornado outbreak.

http://tinyurl.com/2eled3

Here are a few things that happen when a tornado strikes a house.

1. Peaked roofs act like aircraft wings. High speed airflow lifts the room off the structure, which is then more vulnerable to collapse. Once this happens, the house tends to come apart like a deck of cards.

2. High speed air striking the structure can blow holes in structurally weak areas (garage doors, picture windows, etc.), damaging the structure and rendering it more vulnerable to collapse.

3. High speed debris can poke holes in the structure, again rendering it more vulnerable to collapse.

A factor in determining what happens to a house is the quality of the home construction. The nail joints between structural members help determine how fast winds need to be before the roof is damaged. Also, the way the house is fastened to the foundation makes a tremendous difference. Tim's presentation had several pictures of homes that looked only lightly damaged - except they had been picked up off the foundation and set in the swimming pool. When you see those pictures of two houses, one destroyed and the one next to it untouched, it was probably because of different construction specs.

Since you have a basement to put a shelter in, you probably don't have to worry so much about flying debris. You may have to worry about having the house falling on top of you. If you roof your shelter, you might want to think about running some cast iron pipe in it to help resist collapse due to debris on top of it. If you have the opportunity, having your roof joists secured with hurricane clips may help keep it from crashing in on you to begin with.

THanks for the info guys. I'll take a look a the outdoor mini domes. Those seem like the best bet.

If the water table is low enough, you can also get fiberglass underground shelters. You dig a big hole, add gravel for drainage, drop it in, anchor it (to resist floating during heavy rain events) and backfill. Here's an example. You'd just need to find out what's available in your area.

Build a dome, then cover it with a foot or so of soil, and plant it to clover and wildflowers. There's nothing for the wind to grab. To others, it just looks like a planted berm.

Personally, I prefer the half-underground domes of architect Nader Khalili, but I can't find any photos. All they show now are the ugly continuous-bag things.

Sue

Hmm, I've seen tornado paths that have scoured the ashpalt and concrete roadway fairly completely. I would much prefer to get below grade a few feet if possible. Unfortunately here in Florida nearly all residential is without a basement due to the amount of water in the ground, at least from what I've seen here just north of Orlando. We had a tornado scare just before Xmas here, and I was left with the prospect of putting the whole family in the guest bathroom tub surround. Not what I'd call secure. I am told that the tornadoes that do touch down here are not too strong, typically iF0 or iF1 at most. iF5's are the road rippers I guess.