Outdoor warning sirens

After adding my last post to Google Plus, a friend asked my thoughts on tornado sirens. I replied that I thought they provided a rather poor return on investment. This eventually lead to a day-long discussion with a coworker who disagrees with my assessment. Since I’ve never put my opinion on sirens in a blog post, I figure it’s time to do just that.

First, I am of the opinion that sirens serve an important role in public safety. In places like parks, golf courses, and common outdoor gathering areas, sirens are an excellent way of communicating a single message: “seek shelter”. Sirens are unable to communicate why shelter should be sought, when it is safe to come out (though some jurisdictions will re-sound sirens as an all clear), or what the threat is. Some siren systems lack battery backup, occasionally rendering them inoperable at the most inopportune times. Sirens also suffer, as do most alerting systems, of being stuck in a county-based warning system that no longer exists.

Although they are not intended to be indoor warning devices, some people still rely on them as their primary means of receiving severe weather alerts. When close enough to a siren, this can be fairly reliable, but it’s not always the case. My house is 1000 feet from the nearest siren and during tests it is quite audible (uncomfortably so when the windows are open). During heavy rain, it is not nearly as noticeable. I have little doubt that I would sleep through an overnight siren sounding if it happened during a heavy rain.

So what, then? Since the 1970’s, NOAA Weather Radio has served the country well. It provides both alerts and routine weather information around the clock. Unfortunately, it’s also stuck in the 20th century. County-based alerting simply cannot continue to dominate our warning dissemination systems. If the weather radio system were to send warning coordinates along with SAME codes, receivers could optionally determine if the alert needs to be sounded. In addition, most counties are served by a single transmitter. Each transmitter should have a redundant backup, located far enough away to be unlikely to fail from the same event (e.g. power outage, tornado), but still able to cover the assigned counties.

The current state of sirens in Tippecanoe County includes coverage of all areas I propose require it (and probably some that don’t). There are still, by my calculations (see note 1), approximately 25,000 people in the county who live outside the audible range of sirens. In order to cover the entire county’s land area, the initial investment would be $960,000 to $2.7 million (see note 2) with an annual maintenance cost of $115,200-324,000. (see note 3)

I wanted to look at the costs for all thirteen counties served by the WXK74 transmitter in Monticello, but it turns out the siren count information is not easy to find. WTHR in Indianapolis did some of the work for me, but the rest had to be independently researched. Sadly, some Emergency Managers don’t want to disclose even a count of the sirens in their county. As a result, I was only able to obtain authoritative siren counts for Cass, Clinton, Howard, and Tippecanoe Counties.

Using the same strategy as for Tippecanoe County, I calculated what it would take to get these four counties to 100% siren coverage. The recurring costs are $774,00 to $1.44 million. This after an initial investment of $6.42-12 million dollars. And remember, that’s just for four of the fourteen counties, only 30% of the land area covered by WXK74 (roughly 65% of the population).

What would happen if instead of sirens, we added a second transmitter site and bought every household in the covered area a $50 weather radio? The cost of the transmitter would be about $75,000 (see note 4). Buying the radios would bring the cost up to roughly $9.84 million, which is in the range of covering 65% of residents with sirens.

Of course, this is entirely academic. Sirens are funded at the county level, whereas weather radio is a federal project. It’s not easy to just move the money around. There’s also the alert-granularity issue that needs to be resolved.

Given the economics and the richness of information, it makes sense to push for more radios instead of more sirens. Sirens have their place, but those places are limited. The Indiana Department of Homeland Security guidelines would suggest that many local cities and towns should not have sirens at all (except for parks). Ultimately, weather alerting requires a defense-in-depth approach. Sirens are one layer in certain situations. Weather radios are another, more broadly applicable layer.

A third layer is the Wireless Emergency Alert (WEA) system that is being deployed. Unfortunately, it requires a relatively modern smart phone, so I expect the penetration rate is still fairly low. It, too, suffers from a lack of geographic granularity (although probably better than either weather radio or sirens), and sparseness of information (WEA messages are limited to 90 characters). There’s also people who don’t have their phone by their side at all times. Some people actually leave their mobile devices in other rooms sometimes? Quelle horreur! Disturbingly, WEA does not interrupt phone calls, meaning a long gab session will result in you receiving a warning after it has expired.

Given budgets and politics at all levels of government these days, I’m sad to say that I don’t see any of the existing deficiencies being resolved any time soon.

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Increased complacency about severe weather benefits no one

The number of meteorologists in the United States is very small.  According to the Bureau of Labor Statistics, less than 10,000 people are employed as atmospheric scientists in non-faculty positions (anecdotal evidence suggests that the number of people holding meteorology degrees is significantly higher. To wit: of the 12 people in my graduating class, four are meteorologists).  With such a tiny fraction of the population trained in atmospheric science generally, and severe storm meteorology specifically, it should come as no surprise that the public knows relatively little about severe weather.  With the small number of meteorologists, a heavy reliance is placed upon the media and local officials to convey information.

However, while the media and local officials may get more exposure to weather information, they do not necessarily understand it any better than the rest of the general public.  This leads to newspapers reporting that a “local tornado warning was issued” (only the National Weather Service issues tornado warnings officially, and causing confusion about this does not help the public interest) after a “funnel cloud on the ground” was sighted (a “funnel cloud on the ground” is more properly known as a “tornado”, but in this case it was more likely a mere “scary-looking cloud”). It leads to emergency managers sounding warning sirens when the greatest threat is heavy rain and sub-severe winds.  And it leads to confusion and eventual complacency for the public.

Meteorologists have enough trouble fighting complacency as it is.  The most recent data from the National Weather Service indicates that 76% of tornado warnings are false alarms.  This is not because of incompetent meteorologists.  It is a limitation of available observation systems (radar), of the understanding of tornadogenesis, and of the (quite reasonable) belief that it’s better to overwarn than to miss a tornado.  Additionally, since tornadoes are often relatively small and short-lived events, it may be that some of these false alarms are not so, but there are no reports thus the warning remains unverified.  The upshot of all of this is that it’s very easy for the public to not take warnings seriously.

I can, perhaps, understand the reason the Tippecanoe County Emergency Management Agency (TEMA) decided to sound the sirens last Saturday.  A street festival was about to begin in downtown Lafayette, and many people were moseying down Main Street.  The wind and rain had already begun clearing the streets before the sirens sounded, and no one seemed to be in any additional hurry when they heard the beautiful wail.  It can argued that the sirens were sounded appropriately in that case, but the public mindset is that the sirens are “tornado sirens”, so sounding them for non-tornadic events (especially events that posed such a dubious threat) does a disservice to the public because it increases complacency.  In this specific case, the sirens added nothing helpful, and thus should have remained silent.

Were this an isolated incident, I would not have felt compelled to write this post, but TEMA during the Mark Kirby era has been quick to sound the sirens.  In my circle of meteorological friends, there are two common consequences to rainfall: 1) the Indianapolis radar goes out of service, and 2) the tornado sirens are sounded in Tippecanoe County.  If I’ve associated the sirens with rainfall, surely there are others in the county who have done so as well.  So who benefits from sounding the sirens so much? No one.