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The facts: Too many problems associated with tornado warning sirens

Posted by Kevin Fischer on June 22, 2010

Tornado warning sirens have provided a public service for decades.

They’re also imperfect with many inherent problems. But don’t take my word for it. I offer the scholarly view of Emily Laidlaw, associate scientist for the Societal Impacts Program at the National Center for Atmospheric Research in Boulder, Colorado.

Laidlaw writes in the January/February 2010 issue of Weatherwise magazine, “The Controversy Over Outdoor Warning Sirens.” She opens with an account of the 2008 tornado that ravaged a camp in Iowa, killing four scouts, noting that a siren probably saved some lives. Here are excerpts from that point of the article certain sections emphasized by yours truly:


“The Little Sioux Scout Ranch tornado is a text­book example of how outdoor warning sirens should be utilized—in conjunction with comprehensive preparedness and weather awareness, as part of a warning net­work of multiple information sources. But sirens don’t always work as intended. Siren, Wisconsin, for example, was hit by an EF3 tornado on June 18, 2001. Unbe­knownst to most residents, the town’s siren sys­tem had been disabled by a lightning strike the previous month. Accustomed to relying on sirens, many residents expected them to sound when the tornado was imminent. The sirens did not go off, and three people died.  

Scientific literature highlights a number of pit­falls of using sirens, including unrealistic societal dependence on them, desensitization towards them, sound-limiting geographic factors such as wind direction and varying topography, ineffectiveness in elderly and hearing impaired populations, and the fact that sirens are designed to be heard only in out­door settings, such as at picnics or baseball games. In addition, there is no standardized policy for how or when communities activate sirens, meaning that a person from Nebraska who normally hears sirens and heads to her basement to seek shelter from a tor­nado might visit Washington’s coast and not realize that the same siren tone now means a tsunami may be approach­ing and that she should seek higher ground. Simi­larly, a person from Colorado who assumes that a siren indicates a need to seek higher ground due to flash flooding might head outside into the path of a tornado in Tennessee. In Virginia, a siren might mean straight-line winds of 80 mph are imminent, while in a small town in Kansas, the siren could simply mean it is time for lunch.

Even the phrase ‘outdoor warning sirens’ some­times evokes controversy.  ‘Calling them ‘outdoor warning sirens’ is con­fusing to people,” said Mark Widner, emergency preparedness manager for the city of Independence, Missouri. ‘There isn’t a person alive who doesn’t expect to hear them in their house.’

Sirens aren’t as glamorous or intriguing as new e-mail and cell phone alert systems, and they’re expensive. One siren can cost anywhere from $10,000 to $50,000, depending on its specifications. Many new residential developments consider sirens an eyesore and mandate that they must meet a vari­ety of aesthetic requirements before being installed, which only increases the cost. All of this can cause community officials to stop short of installing siren systems, even after a disaster.

On May 13, 1980, a vicious tornado struck the town of Kalamazoo, Michigan, killing 5 people, injuring 79 others, and leaving 1,200 bewildered res­idents homeless. A post-event survey by University of Georgia researcher Thom­as Hodler found that sirens in the area sounded, effec­tively warning two-thirds of the affected population. In the storm’s aftermath, offi­cials estimated that only 17 percent of the city’s residents could typically hear existing sirens, but a $150,000 request for better siren coverage had been rejected.

Sirens, frequently cited in warning research literature as the second most common source of weather warning information for the general public, are a passive warning method. The average per­son can have no television, radio, or phone service, and be complete­ly unaware of a severe weather threat and yet still be warned when a severe weather threat is imminent. All other technologies require some sort of action by the end user, even if a person receives the necessary equipment for free.

A large percentage of emergency managers and meteorologists, for example, maintain that the average person would be better served by receiving severe weather warnings from a NOAA weather radio rather than a siren. First, weather radios are designed to be heard indoors. Second, they appear to be more cost effective than sirens, ranging in price from approximately $30 to $110. 

‘Sirens are less effective and less dependable than a weather radio, and they’re late,’ said Paul Johnson, director of the Douglas County (Nebras­ka) Emergency Management Agency. ‘You’ve got something that’s less effective, it’s late, and the cost has a legacy to it every single year,’ he said.

Research by Walker Ashley and colleagues at Northern Illinois University pointed out that siren systems are less effective during nocturnal tornadoes, which they found were 2.5 times more likely to cause fatalities than tornadoes occurring during daylight hours.”


To be sure, Laidlaw provides pros about warning sirens. However, there are far too many question marks, including the risky scenario of supplying a false sense of security.

Laidlaw concludes:


“The greater challenge, then, falls to a commu­nity of integrated meteorology and social science researchers to better understand how people make decisions during warnings, whether forecasts for weather threats are communicated effectively, how people perceive and interpret that information, and how emergency managers and other community officials can better use tools, such as outdoor warn­ing sirens, to save lives.

As Ashley and colleagues wrote at the conclu­sion of their 2008 study on vulnerability to noc­turnal tornadoes, ‘We must begin to stare down these questions and not sidestep them with the assumption that ‘technology’ will deliver complete and successful mitigation against these events in the future’.”


You can read the entire Laidlaw article here.