Planning to respond to tornadoes and actually building for them are different, however. Model building codes would require contractors to frame houses and roofs that withstand hurricane-force winds. But not all states adopt those models, and the ones that do frequently lower wind standards, according to a study of coastal states last year by the Insurance Institute for Business and Home Safety.
Even after a tornado, a community may not change building codes for a variety of reasons, including fear from homeowners who were unscathed that their lack of tornado-resistant features could affect their property values.
Joplin has made some small building code changes. A new house must have hardware, called hurricane straps, that secures the roof more tightly. Bolts securing the house to the foundation now have to be placed four feet apart, rather than six. Walls made of concrete or cement need steel reinforcement. Such simple, inexpensive changes should mean that a tornado has to be strong enough to lift up the whole house — not just the roof — before it can do structural damage.
There isn’t good data on how many communities in tornado-prone places require such protection built into new houses. But even in those regions, according to the Insurance Institute, the chances of a house being hit by a damaging tornado could be as low as 1 in 10,000.
Shelter from the storm
One thing Joplin did not do after the May 2011 tornado is require people to add storm shelters or safe rooms. Well-built shelters protect people from debris — the main source of death and injuries from tornadoes. But shelters cost $2,500 to $10,000 to build.
Many in Joplin assumed the expense anyway, and the city has especially focused on fortifying community shelters and safe rooms in schools. One engineer estimated Joplin and the region are adding 750,000 square feet of public shelter space — about $120 million worth. That’s enough to harbor 100,000 people.
About half of the homes rebuilt within a year of the tornado included a shelter, according to one official’s estimate. Stammer himself did not have to rebuild, but added a shelter anyway, because of how quickly the tornado formed. Stammer said he realized that had the tornado hit at a different point of the day, he would not have made it to his office emergency bunker, where he usually directs storm response.
FEMA has helped cover the cost of residential shelters in some states, but some question the practicality of broader government programs or requirements that would force people to install them.
Kevin Simmons, an economist at Austin College in Sherman, Texas, has analyzed what it would cost for Oklahoma or Alabama to fund shelters for every single household, and found it would cost Oklahoma between $5 million and $10 million per tornado-related death and Alabama about $40 million per fatality — an expense that may be hard to justify.
That’s because dying from a tornado is only slightly more likely than being killed by lightning. About 70 people a year are killed by one of about 1,200 tornadoes that hit the United States, according to government data. Lightning kills about 54 people a year.
Even in 2011 — a horrible year with 500 more tornadoes than is typical — the storms killed 553 people. Car accidents, meanwhile, killed about 690 people per week in 2009, and that was an unusually low number.
“If you’re going to force people to spend money, is it logical to force them to spend an extra $10,000 on a house when their biggest risk is dying in a car?” asks Tim Reinhold, chief engineer at the Institute for Business and Home Safety.
For anyone who’s been through a tornado, perhaps the real value of a shelter is peace of mind.