April 1, 2015

Counting Storm Shelters Along the Highway

Filed under: Severe — Erin @ 12:54 am

Not long ago, during spring break, I went to Huntsville, Alabama with family on a quick getaway.  We’d had a harsh three weeks of winter conditions in an area that is unaccustomed to them, and which is certainly unaccustomed to four winter storms in about twenty days.  We were also under assorted conditions of stress from work, school, and preparation for the future.  We needed the trip, short though it would have to be.

No one in the car really wanted to drive on I-20/I-59.  That stretch of interstate between Tuscaloosa and Birmingham is incredibly nerve-wracking and dangerous, and is not something I’d recommend to any driver unless one particularly savors the thrill of bumper-to-bumper 75 mph across three to four lanes and people passing with only feet to spare.  We took the state highways instead.  Some of the drive took place on Highway 43, a winding but generally pleasant stretch of road that passes through such Alabama towns as Hamilton and Hackleburg.

It was as we approached Hackleburg that we saw the first unusual scene:  a swath of trees snapped, long denuded of leaves, bent down flush with the ground at assorted angles.  The realization hit all of us at once.

The track of the EF-5 “Hackleburg tornado” (really an extremely long-tracked tornado that began in far western Alabama and continued a little into Tennessee) paralleled Highway 43 early in its lifespan, and EF-5 damage was observed along this part of the path.  The destruction we saw was not the organized logging of a timber company.  They weren’t even the type of trees likely to be felled for commercial purposes.

It has been almost four years, and yet these downed trees still remain, a stark reminder of the violence of April 27, 2011.

We continued our drive.  As we moved into Hackleburg, we saw the first one along the road.  A heavy, inset, but otherwise unassuming rectangular door that opened into what appeared to be a small room built into a slope on the property.

“Storm cellar,” somebody remarked matter-of-factly, with no alteration of tone or pitch.  It might have been me.  I don’t recall who noticed the first one.  We were all pointing them out before the end of it.

The “Hackleburg tornado” took 72 lives in rural and small-town Alabama, scouring 132 miles with its fury.  The official survey claims that the winds were at least 210 mph.  I am convinced that they were much higher than that in places.

We talked about things we remembered about this tornado.  I was pretty sure that it had created a “situation” at the nuclear power plant in northern Alabama.  It had.

“Storm cellar.  Looks like the same kind as before.”  And indeed the second one we noticed did look like the same design as the first one.

Although they are generally acceptable for shelter in most tornadoes, I am firmly of the opinion that basements and above-ground safe rooms (even reinforced) are insufficient to guarantee safety in EF-5 tornadoes.  There have been basement fatalities before.  I particularly recall that they happened in the 2008 Parkersburg, IA EF-5 tornado.  Think about it:  If a basement is even partially above surface level, or the flooring above it is not specially reinforced, then just what exactly is to prevent an EF-5 tornado (capable of leveling a house down to a bare slab foundation) from exposing a basement and then descending into it?  If a safe room is above-ground, what is to prevent an EF-5 tornado (capable of hurling heavy metal tanks up to a mile, as happened in the 2013 Moore, OK tornado) from tossing a massive object right at it and crushing it?

“There’s another storm cellar.”  Again the same type.  Most likely the same contractor installed them.

I have some misgivings about the notion of building earthen walls around prefabricated storm shelters, particularly those plastic rooms that Southeasterners frequently saw advertised after the 2011 tornadoes.  The tornado that I drove away from that day, the EF-5 Kemper/Neshoba tornado, dug trenches into the ground 2 feet deep.  The storm shelters that we saw along Highway 43, however, appeared to have been built into natural embankments.  I hope they are sufficiently deep into the ground that they could not likely be exposed by another monster of that sort.

“Another storm cellar.”

We were all pleased to see the residents of Hackleburg being prepared.  It must have been an unimaginably traumatic event.  I didn’t even lose anything, but merely the fear/expectation that I was going to lose everything left me with a mild case of PTSD-like symptoms every time the anniversary approached.  In order to be sure of this, I would have to make the drive again with someone marking placing markers on a GPS-enabled map whenever we passed a house with a shelter, but it is even possible that these were all people who lost their homes in the 2011 tornado.  They were certainly close to the EF-5 damage path, if not directly in it.

These appeared to be homes of middle-class residents.  It should be easier for everyone to install a—

“Storm cellar.”

By then we were simply saying the words.  It was almost like another road game, such as counting cars of a particular color.  As we passed through Hackleburg proper, we couldn’t help but observe how much construction appeared to be quite new.  Even the road had a new stretch of pavement, identifiable because of its smoother surface and different, darker color from the surrounding road.  The tornado did tear up the asphalt as well.  Intense tornadoes often do that.

“Storm cellar.”

If this stretch of road is representative of the community, that says something very positive about the residents of this area.  I don’t support unfunded mandates to require private homeowners to have basements or storm shelters, because I think people should have the right to face private, personal risk as they see fit (after all, I did precisely that by choosing to hit the road to evade an EF-5 tornado, against the recommendation of the National Weather Service), but I am very glad when people do take the initiative to protect themselves and their families in this manner.  I am in favor of the “carrot” of permanent tax credits for any expenditure of this nature.

There were six homes with the same kind of earthen, in-ground storm cellar just along Highway 43 between Hamilton and Hackleburg.  I’ve never seen that many in such a small area before.  It might not even be noticed by most people, especially people who did not know that an exceptionally violent tornado had occurred in this place four years earlier.  But those of us who did have that bit of knowledge, and who still look at things outside the vehicle instead of some sort of onboard entertainment, noticed this series of doors opening to rooms in the ground.  It was a subtle indicator of something different about this area.

Trauma changes people.  What we saw that day, March 11, 2015, was proof positive that it changes communities too.

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October 19, 2011

NWA 2011: Thoughts About Tornado Warnings and the Casualty Count

Filed under: Severe — Erin @ 7:56 pm

I attended the National Weather Association’s conference in Birmingham, Alabama, for two days.  Toward the end of the second day, the main focus of the talks was the terrible death count from tornadoes for 2011, and most of the speakers were coming at the problem from the perspective of social science such as psychology.  It is understandable that people would want to better understand what happened in an anomalous, outlier year such as 2011.  It is understandable that people would want to find out if the catastrophe was a result of factors that can be easily changed, and that they would even be biased toward that hypothesis.  (One presentation even mentioned the “optimism bias”—a concept that seems a bit strange to me as a natural pessimist, but I can readily see that it would exist in most people, and I would say that this is a perfect example of it.)  My intention here is not to call anyone out.  However, I think that a lot of the research is, frankly, barking up the wrong tree.  There are also some very serious flaws with some of the studies themselves.

The bulk of the research involved surveys of people from the areas that were impacted by tornadoes in 2011.  The surveys contained questions about NOAA watches and warnings (whether people received them, how they received them, whether they were understood) and people’s responses to these messages.

Here are some points I took away from the social science presentations:

  • An overwhelming majority of people in impacted areas did receive warnings.
  • A very small minority of them immediately went to shelter after receiving a warning from the first source.
  • A rather large plurality sought out additional information from TV, the Internet, or personal confirmation to determine if the tornado actually existed and would potentially affect them.  This was more likely in people with higher levels of education and in people who knew more about the weather.  (I would like to note here that this is exactly what I did when the east-central MS EF-5 tornado of April 27 was heading my way.  I did not immediately barricade myself under the stairs when I heard the warning.  I looked at radar to identify a probable debris ball signature and plotted its projected path to go right over my house.  I then grabbed my cat and got out of town.  The tornado lifted, but if it had stayed on the ground, I could have been killed as a result of following the canned advice rather than reasoning out the best course of action for myself!)
  • A minority of people chose to completely ignore a warning.
  • When asked how likely they, personally, thought it was that their area (of what radius?  I don’t recall if it was stated) would be significantly impacted as a result of bad weather mentioned in a warning, the most common answer was less than a 25% chance.  The social scientists said that they wanted people to guess a nearly 100% chance, but in fact, the scientifically and statistically correct answer was less than 5%.  Interestingly, this arguably refutes the “optimism bias” argument in that people did give a more pessimistic judgment of their risk level than was really the case, just not pessimistic enough to suit the social scientists.

The social scientists seemed to be dismayed by the fact that people were less likely to immediately dive for cover the more educated and weather-savvy that they were.  Needless to say, this is an odd message to deliver to a room full of meteorologists (many of whom actively seek out bad weather in their vehicles).  What is the point here?  “Ignorance is strength,” to quote from Orwell? Let alone that people can’t exactly become less weather-savvy, less educated, or more paranoid about the personal impact from a storm if they already know better.  This is an example of trying to close the barn door after the animals have escaped.  These things are what people do, and with the proliferation of web phones with more and more features that allow people to have access to information virtually anywhere, these behaviors are only going to become more common.  This means that they are the behaviors that must be worked with and planned for.  Trying to force people into a state of unnecessary and statistically unwarranted fear is not going to work.  Nor is it a good idea to try to bully people into not seeking out information and using cognitive reasoning.  I’m no social scientist, but I can tell you that if this is attempted, the most likely reaction is a rebellious contempt for “the government” for “trying to make us not question, not think for ourselves, and do as we’re told.”  I would be just about willing to guarantee it.  It could backfire badly.  People ultimately have to be responsible for their own decisions.

Furthermore, there was absolutely no evidence given that people who sought out more information first were more likely to be injured or die in an event, and obviously the survey methodology required interviewing people who did not die.  Knowledge about what the people who died did must come from people who were with them and survived.  However, I never even saw that there was a distinction made between the group of people who were in the path of the tornado and were uninjured or had only minor injuries, and those who were severely hurt or killed.  It would have been useful to find out if the people who were severely harmed did anything differently from those who were more or less okay.  Given that at least one of the surveys was conducted via e-mail shortly after the event in question (the Tuscaloosa tornado), I would expect that there would be very few people who were severely injured who even participated in it, because they would have been in the hospital.  In effect, the social scientists gathered statistics about a control group and presented it as though it represented the experimental group.  In this situation, the statistics about behavior patterns following a warning mean nothing in themselves.  There is nothing (survival/non-survival, minor/major injury) to correlate them to.  Implying that these behaviors caused the death toll to explode is unsupported speculation.  The one survey I saw that definitely interviewed people who had lost loved ones or who were severely injured was conducted in Smithville, MS, and these authors did not make any wild inferences about how seeking out additional information had led to the deaths.  There is simply no data support for it.  The only situation where it might make a difference is when the lead time is basically zero and every second counts, which was not the case in the April 27 tornadoes or the Joplin tornado.  (I had a lead time of about 25 minutes, which was enough for me to get my cat and laptop and go 18 miles away.)

There was one data omission that is, in my perspective, more important than any behavioral survey.  One table that I did not see in any of the social science presentation was this one:

F Scale Killer Tor Fatalities
F0 1 1
F1 3 4
F2 15 24
F3 23 76
F4 13 160
F5 6 282
F? 0 0
TOTAL 61 547

(Credit to the Storm Prediction Center: http://www.spc.noaa.gov/climo/torn/fataltorn.html)

That is, 95% of all tornadic deaths this year occurred in EF-3 or higher tornadoes, which will destroy most or all walls in a house.  EF-5 tornadoes can even expose the basement and descend into it (it is a myth that the funnel would magically stop at the ground level if an open hole existed for it to twist into), sucking people to their deaths.  And it gets even more significant when you dig deeper into the data.  A look at the list at the top of that page shows that only 4 of the deaths from EF-2 or weaker tornadoes occurred in permanent houses.  I don’t know exactly what happened there, but it could have been extremely bad luck such as a tree falling on the house, a piece of heavy furniture, or a piece of timber causing injury.  It could have been a weak structure.  The point is, this is very rare.  The rest of the deaths in EF-2 and weaker tornadoes were in trailers, vehicles, outdoors (all highly dangerous places to be in a tornado) or were unknown.

I respect the research into this year’s terrible tornado casualty count.  It is important to determine exactly why this occurred, and one question that did need to be answered was whether it happened because of bad decisions.  This is the question that the social scientists have attempted to answer.  I simply disagree very strongly with their apparent conclusions, as I think they are unwarranted by the questionable research methodologies, and are little more than speculation.  My contention is that the catastrophic death toll is directly attributable to major, violent tornadoes, the kind that obliterate entire homes, happening to occur in a lot of populated areas this year.  In short, it was a statistical outlier year.  This classification does not address the underlying structural problem of the Southeast, which is that effective storm shelter is not commonly available for the most violent events, but that’s not an easy problem to resolve.  Unfortunately, in my opinion, it is this hard problem, rather than comparatively easy ones regarding bad decisions, that must be answered if this type of death toll is to be prevented from ever happening again.

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May 26, 2011

What’s Going Wrong?

Filed under: Severe — Erin @ 9:23 pm

This year has had a truly terrible human toll from tornadoes. The current fatality count, approximately 500, is an order of magnitude larger than the average for an entire year. It is to be hoped that this number does not substantially rise, but we do have June, the tropical season (which is expected—and I agree—to be quite active and have a higher than average risk of U. S. hits), and the cool-season secondary severe weather peak. However, this figure is horrible enough even if these periods of higher risk produce absolutely no damaging or fatal tornadoes. Something went very wrong this year, something that has not gone this wrong in almost 60 years, and it is important to determine what it was.

Having followed the stories in a fair amount of depth and from multiple sources, I have developed some suspicions of my own about what some of the problems were. These are problems that either appeared in multiple situations or that appeared in sites where high concentrations of deaths occurred. Other people may form their own opinions, but in whatever analysis of 2011 that takes place (and you can just about guarantee that something of the kind will be done), I hope that the following issues are seriously examined.

1. Safety recommendations for urban residents.
One ugly lesson we have had forced on us this year is that, contrary to long-standing myth about cities being safer than rural areas in tornadoes (perhaps because of the idea that buildings will provide resistance?), a city may well be the worst place one can be in a violent tornado. Even in the age of high-resolution Doppler radar, real-time chaser and spotter reports, live coverage, and 20-minute lead times for warnings, we now know that an EF-5 tornado striking an urban center can result in a triple-digit death toll, as happened in Joplin, MO. It is easy, in retrospect, to understand why a densely packed urban area may be the worst possible place to be. Other than high-rise office buildings, there is no safe place to be. High-rises, according to the EF-scale, will not be demolished even in an EF-5; the maximum expected damage is “permanent structural deformation.” However, directing everyone to the nearest tall office building is a ridiculous “safety” recommendation, needless to say.

What are some other problems with urban areas? Many buildings in the central business district, like fast food restaurants and small businesses, are not constructed to withstand anything like a tornado, and they are simply not safe places to be. Big box retailers will contain very heavy stock that is piled high, providing plenty of potentially deadly missiles. Vehicles are everywhere, and they will become airborne. Designated tornado shelters, which some communities do have, would be useful only if people flocked to these sites well in advance of an actual tornado, because congestion on the roads could result in mass fatalities. Storm cellars would be all but nonexistent, and basements are limited in spatial extent and would be directly beneath the houses, which puts anyone taking shelter therein at risk of exposure to tornadic winds and suction if the house is removed. There is no easy way to get out of danger; traffic congestion will occur if people try to evacuate en masse, putting people in possibly even greater danger than they would have been if they had stayed put. And, of course, cities will have more debris than any other type of community.

We need to seriously consider what kind of safety recommendations can reasonably be given to people who live in town—if any. It is highly uncommon for cities to be struck by EF-4 and EF-5 tornadoes, but it can happen, and the buildings do not provide friction-based wind resistance that would mitigate the effect of violent winds. The situation needs to be looked at to see if any sort of useful specialized safety advice can be given to urbanites.

2. Vulnerability of cell phone networks.
Sometimes when tornado victims are quoted in the news as saying “there was no warning,” what they mean is that they, personally, were not aware of the situation. However, every fatal tornado this year except for one occurred within a tornado watch (link), and that one, an EF-3, occurred within a severe thunderstorm watch. I do not want to sound callous, but there is a responsibility to be weather-aware, which includes awareness of tornado watches and warnings. The outbreaks were all extremely well forecast. Most warnings this year had lead times of 20 minutes or so. In these situations, it is simply inaccurate to say that there was “no warning.” It is passive-aggressively blaming the Weather Service for one’s own failure to be aware.

However, in some cases, there was a legitimate lack of warning, though this is not the failure of the Weather Service. These instances involved the failure of the power grid and the cell phone network, taking down any means by which one might receive weather warnings other than a battery-powered or hand-crank radio. This occurred in some of the small towns that were overrun by the extremely violent EF-5 tornado that traversed northwest Alabama on April 27. I think it also occurred in one of the EF-4 tornadoes of the same day. This is a real problem. Most new phones have the ability to function as handheld PDA, music player, portable gaming device, organizer, Rolodex, e-mail, Twitter, Facebook, and even web browser. With this kind of capability—and none of it dependent on a steady AC/DC power supply—it is easy to understand why people would be reluctant to buy a portable radio. They depend on their phones, and with good reason. However, the cell phone network is clearly vulnerable. If there is significant damage to a tower, down the network goes. This goes for other disasters, including terrorism. The problem needs to be examined to see if these towers can be made more robust. Severe weather outbreaks usually have more than one round, and areas that saw their power and communications knocked out by one (even relatively benign) event can be extremely vulnerable later on.

3. The DTV conversion.
I had a bad feeling about this as soon as the DTV changeover began back in 2009. With the old analog signals, one could have a fuzzy screen—even no visuals at all—and still have audio. With the digital signal, the broadcast becomes choppy, and before long it goes completely black and silent. You have either a near-perfect picture or you have nothing. I have heard more than one anecdote of people in tornado-struck areas who did not lose power until after the tornado hit, but who could not hear the warnings because their TV signal had gone out. I don’t know how many fatalities, if any, were caused by this, but it is a problem that, in my opinion, was severely underrated when the rush to DTV was taking place.

4. Dangerous amateur videography.
There are a lot of videos out there of this year’s tornadoes, and a great many of them were not taken by experienced storm chasers or always-running security cameras. They are also not all taken by people who were a safe distance away from the tornado. One tornado video from Alabama was shot by someone who had a car accident while taking the video! This is a major problem. There is not one thing that can legally be done to stop people from taking video of approaching tornadoes if that is what they want to do, but it is a sad reflection on our society. I don’t blame storm chasers for this. Responsible storm chasers and weather spotters have provided a lot of on-site reports, helping newscasters and people following the situation online know when there is actually a confirmed tornado. Real-time reports of a tornado on the ground helped me decide to evacuate in advance of an EF-5 tornado. Some storm chasers behave highly irresponsibly on the road, and they should be condemned by the rest of the community for it, but overall these people take their hobby very seriously. The videos I speak of are taken by people who just happened to see the tornado and decided it would be a cool idea to get video of it, and the videographers clearly have no knowledge of how far away they should be or where to go if the tornado shifts its path. This particular trend is not the fault of storm chasers; it was produced by social media culture.

5. Lack of shelter from violent tornadoes.
The overwhelming majority of this year’s fatalities have occurred in violent tornadoes, those rated EF-4 and EF-5. This is because these tornadoes will utterly demolish well-built houses, leaving only a pile of debris over a foundation (EF-4) or a bare foundation altogether (EF-5). The Hackleburg, AL EF-5 tornado even buckled the concrete slab foundation of one structure, and the Neshoba County, MS EF-5 (“my” tornado) dug up dirt two feet deep. I think that the odds of survival in these tornadoes are still better than 50-50, but it is easy to see how this kind of situation is incredibly dangerous. The unfortunate fact is that a majority of houses in the South and Midwest do not have basements or storm cellars. My position is that storm cellars are preferable to basements, especially if they have a “fallout shelter” design in which the entrance is not directly above the main room, but is horizontally removed from it. I have read enough accounts of people who took shelter in their basements and were sucked out that (while I agree that basements are clearly preferable to any above-ground shelter) I cannot equate basements and storm cellars. I would also recommend firmly anchored handrails in the main room, in case the door was torn away. The opening sequence of Twister is not myth.

I definitely do not equate above-ground saferooms with underground shelter. These structures are engineered, yes, but they are highly vulnerable on two counts. One, if they are undermined from below, they will roll. Two, the engineering is based on a typical flying missile the size of a 2×4 and a typical flying missile speed of 100 mph. EF-5 tornadoes have wind speeds upwards of 200 mph and have even been clocked as high as 300 mph, though it is a matter of debate whether a large object would travel at these extreme speeds. However, these large objects do travel. In Smithville, MS, the town water tower was dented 120 feet above the ground by a car that became airborne. This is known for a fact by matching paint from the tower and the car. There is video on the Internet of a Canadian F5 tornado in which a whole house is clearly airborne at a great height before it disintegrates.

It’s easy to say, of course, that everyone should have an underground shelter. It is quite another to bring that about. I am opposed on principle to any government mandate to protect people from themselves if there is no risk to other people. This must be a matter of personal responsibility. However, I am in favor of rewarding the decision to install a storm shelter with a tax rebate or credit.  Such credits have been offered in the past, usually to specific regions after particularly high-profile and destructive weather events; I argue that they should be permanent and universal.

These are my suggestions about what should be looked into when the year 2011 becomes part of history, or when people begin to examine what has gone wrong with severe weather preparedness, whichever comes first. Undoubtedly other people will focus on other things. One thing is for certain: We need to know whether this year’s atrocious human toll was in any way preventable, because if it was, it must not be allowed to happen again.

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