Skepticism about “Severe Weather” Sirens

27 Jul
Picture of Benjamen Johnson

by Benjamen Johnson

Summer storm season has been underway in Minnesota for at least two months this year. We’ve already had a lot of severe weather and almost countless activations of the “severe weather sirens.” There’s no question that the criteria for categorizing a storm has changed to allow more storms to be called severe enough to activate the sirens, but what I want to know is does the increased number of siren activations change peoples perception of the sirens. Do people perceive that our counties and cities are “crying wolf?”

Even though recently the NWS did change it’s hail criterion from 0.75″ to 1″[1], other criteria have diluted the definition of a severe storm[2]. At the risk of sounding old and crotchety, I remember when a tornado warning meant they actually spotted a tornado. This coupled with the fact that cities and counties  have their own criteria for sounding the alarm can mean sirens are activated even for severe thunderstorms with straight line winds or hail[3].

One week this year, we had the sirens go off five times (that I heard) and nothing happened in our area; there was even one confirmed false alarm. I really wonder whether people will become acclimatized to the sirens when they go off so often, especially with a False Alarm Rate of 80-90% in some areas[4] — that they’ll fail to take shelter when they really need to because nothing happened the last 20 times the sirens went off. I know I have. It’s gotten to the point where I don’t rush the family into the basement when I hear the alarms. I’ll turn on the TV and if don’t see Dave Dahl’s face (or another Meteorologist), I’ll leisurely go to the computer and look up the NWS online and try to figure out what’s going on.

Now I know that the NWS is trying to warn people sooner so that they can get to shelter, potentially saving lives and preventing injury, but if you cry wolf too many times, my feeling is that people just aren’t going to take them seriously.

I know that I’m not the only one who thinks that way — although it was hard to find opinions on the whether increased activation of the sirens causes public apathy. I was able to track down a couple of people who have written extensively about the possibility. The first was Roger Edwards. He wrote a well referenced treatise on what’s wrong with the severe weather criteria and how to fix them[5]. I’m not positive about his credentials, but what he says makes sense (dangerous I know). His best quote is:

Moreover, the tremendous increase in warning numbers, especially those verified merely by marginally severe reports or by isolated events unrepresentative of the storm’s impact on the entire warned area, could dilute public confidence in warnings, ultimately endangering lives. This is the “cry wolf” effect, where (for example) a series of warnings in a county over a period of months or years, each verified by isolated dime size hailstones or estimated gusts of 60 mph, creates apathy — leading in turn to death and injury in a devastating event of extreme severity.

James Spann is another meteorologist who proposes that sirens are sounding too often. He even goes as far as saying the sirens should be taken down; they’ve outlived their usefulness and there are many better ways of informing people of impending doom[6].

While I’m not sure I’m ready to tear down the “severe weather” sirens, I definitely think there should be some more study on the effect of repeated false alarm on people’s preparedness for dangerous storms.

Note: I can’t find anybody who keeps records of how many times the sirens have gone off in an area — if records are kept they are probably kept by the same cities and counties that control the sirens, but the NOAA does have a cool page online where you can search for the storm history for your area.

References:

  1. WDTB Webmaster. January 5, 2010. Why One Inch Hail Criterion? In National Weather Service Website. Retrieved July 27,2011, from http://www.weather.gov/oneinchhail/
  2. I did not have time to find a definitive source.
  3. I cannot find the siren activation policies for Ramsey county or my city, but from experience I know they activate the sirens for some severe thunderstorms
  4. Spann, James. June 8th, 2011. The Warning Process Must Get Better. ABC 33/40 Weather Blog. Retrieved July 27th, 2011, from http://www.alabamawx.com/?p=48699
  5. Edwards, Roger. Original publishing date unknown (updates in 2001 and 2003). PROPOSALS FOR CHANGES IN SEVERE LOCAL STORM WARNINGS, WARNING CRITERIA AND VERIFICATION. Roger Edward’s Home Page. Retrieved July 27th, 2011, from http://www.stormeyes.org/tornado/verf/
  6. Spann, James (see #4)
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6 Responses to “Skepticism about “Severe Weather” Sirens”

  1. Greg Laden July 28, 2011 at 9:17 am #

    Most of those are not “false alarms” in the sense that there was no storm. Think of it this way. You see a toddler toddling towards a street and a car coming down the street so you shout a warning. The toddler ignores the warning and the person driving the car does not see the toddler or hear the warning.

    Then, the car whizzes by but happens to not hit the toddler. Was that a false alarm? No, it was just a circumstance where the predicted event can’t be predicted accurately enough.

    Having said that, it may well be that the alarms go off too often. The other day I stood in front of my house watching a storm. A tornado passed closely enough to my left that I could hear it, and debris fell on my lawn (nothing dangerous). The siren did not go off. Several times this year, however, the siren did go off and there was not a tornado this close, and only once did the winds to any damage. From this I’d say that the sirens are only vaguely associated with damage and danger.

    But, that is the point. I think what needs t happen is that people need to learn how to associate warnings with action in a way that is appropriate. I work in the basement of my house most of the time . When there is a severe storm, I know exactly what to do: Nothing! But if I’m with the 1.5 year old upstairs I’ll pay more attention and keep him away from the big glass window. In a tornado warning (not watch) we switch to playing downstairs (the basement) rather than upstairs.

    When I first moved to Tornado Ally (from Nor’easterland) I lived in a house with a typical cellar type basement. I went ahead and fixed it up so there was a place to go and hang out comfortably. Then, when there were tornado or severe storm warnings, we would just go there, no big deal. That way we did not need to worry about the degree of accuracy of the prediction. (My diligence in moving to that house was spurred on by the fact that the lot was hit with the Har Mar tornado many years ago with damage still showing on the trees, and the front yard was hit with a small twister between the time of signing the purchace agreement and moving in!

    Here, where I live now, when there is a severe storm outside you can’t hear the sirens unless you listen carefully or actually go outside. Thus … the weather radio.

    By the way, you’ve got a great blog here!

    • Benjamen Johnson July 28, 2011 at 10:48 am #

      I do know that the false alarm I mentioned was actually a false alarm; I went to the NWS website and they said it was — I don’t remember the exact wording.

      But now that I think about it 1) the false alarm rate I stated was the worst case and not representative of the true rate, 2) I wonder what are the criteria for a false alarm, and 3) I wonder where James Spann got his numbers from. I would bet many cities and counties don’t keep track of siren activations, unless they are required to.

      I agree that “people need to learn how to associate warnings with action in a way that is appropriate,” but everything we’re told by the authorities and the media seem to contradict that. The simple message is run for the basement every single time you hear a siren. Yet the goal is to sound the sirens way before they know something is actually heading into the area, sometimes 20 minutes or so in advance. Which actually would give most people the time to check the computer, TV, or weather radio to evaluate what they should do.

      What I’d like to see: If they say the sirens mean run for shelter, then only sound the siren five minutes before we actually need to run for shelter, not 20 minutes prior to “a storm that has a history of producing large hail.” I wonder what the response to that would be?

  2. Greg Laden July 28, 2011 at 11:20 am #

    but everything we’re told by the authorities and the media seem to contradict that. The simple message is run for the basement every single time you hear a siren.

    Exactly. Did you know that the best practice on Earth for humans in taking antibiotics is usually to double-load the first dose (take two pills instead of one)? But in the US we are never told to do this. I assume this is because we are too stupid to follow such complicated directions, or at least, we are thought to be too stupid.

    If the weather people tell you to look out the window first and see what is going on, people would get cut up from the broken glass when the tree branch slams into the house, I suppose….

    The problem with the sirens sounding just before the storm hits is that for many people the storm is too loud to hear the sirens. Which should give you a clue that there’s a storm, so ….

    Maybe the sirens are just out dated. You now about this girl who was killed in the Western suburbs last year (or the year before), right? The sirens in that community did not sound before a tornado hit because the tornado formed, dropped, wiped out a few houses and dissapeared in a very very short period of time. The sirens were blamed for the death, even though there were active severe weather and tornado watches in effect. The kids were playing in the upstairs bedroom and no one was concerned with the storm until it killed one of them. The sad irony in that case is that, as I understand it, the girl was visiting, and her family was back home in the basement because of the storm.

    Clearly, the message here is that sending out and using this information is hard both for the senders and receivers, but not too hard. And there is a cultural convention to not take tornadoes seriously (which is thankfully fading away these days) in this region.

  3. Benjamen Johnson July 29, 2011 at 9:08 am #

    A timely article from Cecil (from the Straight Dope) answers: Is your basement the best shelter from a tornado

    http://www.straightdope.com/columns/read/3007/is-your-basement-the-best-shelter-from-a-tornado

  4. Mully410 July 31, 2011 at 3:49 pm #

    I’m not sure there is better solution. Do we put up with a few false alarms or wait until the houses start flying?

    I became a trained weather spotter a few years ago. One of the first things they taught me was: When the warning is issued, seek shelter. I don’t always have a weather radio on me when I’m outside and don’t have good visibility in my neighborhood, so I appreciate the sirens. http://www.metroskywarn.org/index.html

    Furthermore, if we could have a perfectly accurate and effective warning system, a certain amount of people would ignore it anyway. Heck, plenty of people ignore hurricane warnings and they often get days notice.

    I’m not sure what can be done to increase the effectiveness of the storm warning system. Maybe ban storm photos from the news? 😉

  5. Benjamen Johnson July 31, 2011 at 5:55 pm #

    Lets look at this in a different way. What are the odds of being injured in a severe weather event? How have the sirens improved (or worsened) this statistic? how much time are we sacrificing every time the sirens blow. In short are the sirens making a difference and is it worth it.

    These cost benefit decisions are made all the time, the sirens should not be exempt. I would like to see these numbers, and if these numbers aren’t being generated then it isn’t a science, it’s a pseudoscience.

    The problem is many times when skeptics question public safety issues, we are told to sit down and shut up, how dare we question them if we haven’t been in their shoes, and that we are risking lives by questioning them. (I’ve had a firefighter tell me this right after they told me something that began “in my experience”, not “studies show” or “experiments show”)

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