Wednesday, December 14, 2011

Have We Solved the Tornado Problem (For Residents of Conventional Housing)?

Today was the second day of the NOAA Weather Ready Nation Conference in Norman, OK.

Yesterday, I talked about the fact that 99% of 2011 tornado-related fatalities occurred in locations that were in both a tornado watch and a tornado warning at the time the tornado arrived. I called that a remarkable scientific accomplishment that virtually no one -- inside or outside of meteorology -- is aware of.

Want to know how big an accomplishment the 99% is? Consider: It was recently announced that Albert Pujols will receive $250 million dollars over the next ten years to strike out two-thirds of the time*! Pujols' lifetime batting average is .328, meaning he gets a hit slightly less than one-third of his at bats.

As I have learned more today, I have convinced the "tornado problem" is not homogeneous. So, I want to propose an idea that will be controversial: Weather science has solved the tornado problem for those who live in conventional housing.

Take a look at this graph I presented yesterday. It is a logarithmic graph from NOAA's Dr. Harold Brooks that depicts the death rate from tornadoes (deaths per million population):
click to enlarge
If you take out 2011, the death rate in conventional homes has been cut more than 99.3% as compared to what it was before the tornado warning system was created.

Unfortunately, the death rate in conventional homes will never be zero, especially in F-4 and F-5 tornadoes.

Since zero is impossible, is it worth spending finite dollars and research resources to try to "move the needle" from 99.3% closer to 100%? Before you answer yes, let me go on.

If you look at the same graph above, the black squares show the death rate in mobile homes. For mobile homes, which house more and more American families, the needle has hardly moved at all. The death rate in mobile homes now is about the same as in conventional housing before the tornado warning system was created.

So, here is what I conclude: While we should strive to improve the accuracy, timeliness, and geographic specificity of all tornado warnings we should stop putting effort into specifically improving the safety of people in conventional homes and apartments. Instead, put that money into mobile home safety.

When resources are finite, good management dictates putting those resources where they will do the most good. In the case of tornado safety, that appears to be mobile homes.

Comments are welcome!

* Thank you, Dave Freeman.


  1. Is there really a large pot of money going into conventional homes and apartments? I've heard of some home shelter grants but that pales in comparison to what it would cost to give every mobile home a suitable tornado shelter.

  2. Rob,

    Yes, there are grants for safe rooms that -- in some cases -- pay the entire cost of the safe room. When I learned that today, I was shocked. After all safe rooms are not a "public" good (i.e., a road or food stamps). A safe room in a home is private property that benefits only that homeowner.

    There are other "incentive" programs being proposed. I'm suggesting that resources for education and sheltering be focused on mobile homes.

    Thanks for the comment.


  3. Monster,

    During this afternoon's discussion, I asked, "Why should I, or any other taxpayer, pay for your safe room?"

    The reply, according to the safe room grant advocate, a safe room is a "public good like roads or food stamps."

    All of us drive on the public roads so few have a problem with tax money for that.

    Some believe we need a "social safety net." Regardless of the extent to which we do or do not believe that, if you or I fell on hard times we would be eligible for food stamps.

    However, the safe room differs from the above examples because they are placed inside private property. You or I would never benefit from it. So, I see no reason one taxpayer should provide another taxpayer with a safe room for their home.


  4. I completely agree with you regarding public funding of safe rooms in private dwellings.

    But doesn't that argument also follow for shelters for mobile home parks? Sure it benefits more than just one individual, but it is still private property and it doesn't benefit me if I don't live in a mobile home park.

  5. Steve,

    In theory, if you were driving by the mobile home park, you could probably dash into the shelter...I doubt they would check IDs. But, your point is well-taken.


  6. I disagree with your assertion that the tornado problem has been "solved" for residents of conventional housing. By your own admission, you had to "take out 2011" to come to this conclusion. Therein lies the problem.

    As Dr. Wurman has stated (as recently as the 1st day of the conference you're attending), mobile doppler radar observations indicate that there really aren't that many "weak" tornadoes. To go even further, there are a lot more "strong" tornadoes that just happen to not hit anything (i.e., in rural areas).

    This illustrates the major flaw in our current system of tornado intensity classification based on damage only. If an "EF-4" or "EF-5" tornado doesn't happen to hit something, it's not classified as such - therefore, the statistics as to what kinds of tornadoes are taking place is heavily skewed toward the low end of the scale.

    You and I both know that if you take that EF-4 or EF-5 tornado and roll it into a subdivision made up of conventional housing, the "tornado problem" has not been solved (i.e., Joplin, just to name one example from 2011).

    Unfortunately, with the urbanization of rural areas likely to continue all across tornado alley (and the South), there are likely to be many more 2011's to come.

    With the above said, I completely agree that we need to put sheltering methods in place for mobile home parks. I just don't believe that the conventional housing problem has been solved yet either.

  7. @9:22am. Are you contending 19 minutes of warning in Joplin wasn't enough?

    The problem in Joplin was a less than optimal warning execution along with confusion caused by sounding the sirens for high winds.

    A month before Joplin, an F-4 cut a 22 mi. path through densely populated suburbs of St. Louis without a single death of injury. Those homes have basements.

    When I say the problem is solved, I'm talking from a meteorological standpoint: Virtually all major tornadoes have enough advanced warning for people in conventional homes to take shelter. That is clearly not the case with mobile homes.

    Thanks for the comment.

  8. I was not addressing the warnings, I was addressing your comment: "we should stop putting effort into specifically improving the safety of people in conventional homes and apartments" which seemed to be the main point of your post.

    I re-read the post and still came away with the same feeling, which prompted my original comment.

  9. I accidentally hit submit before I had finished with my last comment.

    Furthermore, you said in your comment "Virtually all major tornadoes have enough advanced warning for people in conventional homes to take shelter".

    That may be true, however they are not likely to be able to survive the types of tornadoes that are out there in a conventional way. This goes back to my point about urbanization and how there are likely more strong and violent tornadoes than weak ones taking place than we know. This is especially coming to light now as once "rural" areas become more heavily populated.

    2011 and Joplin are not flukes that can be discounted from the dataset.

  10. Mike,

    If I fall on hard times and need food stamps, I might also have to move to less-expensive housing. In that case, a government-funded safe room would be every bit as much a "public good" as the food stamps.

    Having less people in the emergency room when a tornado hits might be considered a "public good" too, for that matter..

    (I'm not saying I agree with this reasoning, just that if food stamps are a public good, despite the fact that they are privately consumed in the stomachs of their recipients, why aren't safe rooms in private homes just as "public"?)

  11. @11:26. Sorry I wasn't clear. I'm referring to the lead time and messaging pertaining to conventional homes.

    Mobile homes need different messaging and a rethinking of shelter strategies.

    I'm open-minded about Josh's comments regarding intensities but wish to learn more.

  12. I'm curious. Is there data to suggest that more/different warning time/methods would result in fewer injuries/fatalities in mobile home areas? In other words, how much of the solution is meteorological?

    I suspect that if warnings could be accurately made 1 hr in advance, compared to 10-20 min, that the fatality count would not be measurably different in these high risk, under sheltered, areas. I could be wrong about that though and wonder if there is any evidence one way or another.


  13. Steve,

    Lead time was extensively discussed at the Weather Ready Nation meeting. There is a growing body of research that indicates 20 minutes is about optimal.

    Seems to me that we are going to need some sort of sheltering available either in or in quick walking distance from mobile home parks.


  14. Mike,

    I would agree from a forecast standpoint the current system provides accurate and precise information regarding tornado and severe thunderstorm warnings. The real problem is that there are no standards in how the warnings are disseminated at the local level. Working in engineering there are standards organizations that provide guidance, and set reasonable levels of performance for materials, designs, and processes. Almost all of these institutions are private organizations. Maybe it is time to have a similar private body working on standards for warnings on the local application level. This would give support both in research and information allowing Emergency Managers to move away from the shotgun approach of warning everyone no matter who is affected.

    Mobile homes, both in a park and on a single dwelling lots are significantly more problematic. Some of this could be specified in universal codes for municipalities, just like we see for codes regarding earthquake resistant housing in those areas at higher risk. The 2011 severe weather season, may be a catalyst for those efforts. I once worked for a company in Olathe who's owner did not believe that tornado warnings were important. When the tornado hit KCK near the speedway was being constructed, that attitude significantly changed. Some of his rental property was significantly affected and he was much more aware of the dangers. We probably have a limited window in time to affect changes. Otherwise, it will probably take more deaths to make the needed changes.

  15. Seems to me that we are going to need some sort of sheltering available either in or in quick walking distance from mobile home parks.

    If some sort of collective shelter were built, they would probably be cheaper on a per-person basis to build than individual "safe rooms". And if government grants went to subsidize those, it would not only be a more efficient use of tax money; it would also be much more of a "public good".

    I even have some ideas on how shelters could be built on a very cost-effective basis.

  16. I think there's much more of a problem for apartments than for owned homes. If you own your home, you can make sure to have a way to take shelter, whether that's the basement, an interior closet with a door, or putting in a safe room. In an apartment, you may have none of those things and no way to change that.

    When I lived in tornado country, I lived in three different apartments. The first one had a basement residents were allowed to enter. When we had a tornado warning and the siren went off, we went to the basement.

    The second one was a second floor apartment in a building that had no basement. Our choices for shelter were the first floor hallway, which had a door on one end and a window on the other, or the one interior closet in our second floor apartment (the other two closets had outside walls). (We went with the closet.)

    The third one had a basement but residents were locked out of it. Our apartment was on the first floor, but the only closet had no door. Shortly after moving in, we were awakened by the siren going off...we did have our tornado bag (extra clothes, water and radio) but had not yet decided where to shelter. We wound up in the shower stall in the windowless bathroom, hoping it would protect us and worrying about getting injured by the showerhead (etc.).

    As you can see, two of those apartment situations offered very little protection.

    I think safe rooms for apartment buildings could indeed be a public good. (There's no incentive for an apartment building owner to spend money putting in a tornado shelter when others who haven't will undercut his/her rents. Mandating safe rooms would level the playing field in that regard.)

    Similarly, apartment dwellers could use clearer messaging about what is the best shelter if you cannot go to a basement. Maybe I'm just too inclined to second-guess myself, but I'm *still* not sure I really understand what is and isn't important in choosing where to shelter from a tornado; I'm *still* not sure we made the right choices.


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