As loud as they are, storm sirens can be tuned out.
That’s one of the reasons why on March 1, Henderson County transitioned from a county-wide storm alert system to a more focused module.
Used by the National Weather Service since 2007, the storm-based warning module narrows the geographical focus regarding the area that is alerted of an impending storm by outdoor sirens.
Emergency Management Director Kenny Garrett said the switch came due to a combination of factors.
“Complacency regarding the use of Community Outdoor Warning Sirens (COWS) and the availability of a suitable solution for a more focused alerting process led to the decision to upgrade the way of notifying the public through the use of COWS,” he said.
However, “Complacency was the No. 1 concern expressed to me by a number of members of the public.”
Under the new module, sirens are activated in the areas of the county determined to be most impacted by an approaching storm.
Information obtained from the Henderson County Government website said, “The warned area is defined by latitude and longitude coordinates and depicted by polygons … A two-mile buffer zone is added to all storm-based warnings. This will provide advance warning for people in the general vicinity of the polygon-based warning area.”
Garrett also said the sirens will only sound when the National Weather Service identifies a storm as a certain category.
The storms that blew through Henderson County in early March causing downed trees and power outages, “was a severe thunderstorm tagged by the National Weather Service with the category of ‘Considerable’ due to wind gusts above 70 miles per hour. Had the storm contained wind speeds of less than 70 miles per hour or 1.75 inch hail it would have been a ‘Base’ category and the sirens wouldn’t have been activated.
“The odd part is that more than 80 percent of our severe storms over the past five years have been categorized at the ‘Base’ level,” Garrett said. “If those numbers hold for the future, our sirens will be used less, which will reduce complacency. All other forms of alerting to ‘Base’ severe thunderstorms will continue to be in effect.”
The NWS also has a third category for a storm entitled ‘Destructive.’ To meet this level, a storm has to have baseball-sized hail (at least 2.75 inch diameter) and/or 80 mph thunderstorm winds, according to the NWS website.
A veteran emergency responder and chief of the Corydon Civil Defense, Bryan Coghill, agrees that a focused alert system will help people take the warnings more seriously.
“I do believe people ignored the sirens, especially if the storm was on the opposite side of the county,” he said. “I hope with the new protocol it helps people be more aware, and that it covers the areas needed.”
Garrett said a computer upgrade—costing roughly $11,000—was needed to support the storm-based warning module. (The Henderson County Fiscal Court approved funding for the equipment, according to a past article published in the Hendersonian.)
“A new Windows 11-based computer system was needed to support the upgraded and web-based software designed to talk to the existing siren controller,” Garrett said. “This was a much less expensive option than adding additional modules to each siren location to achieve a similar solution. The web-based software is purchased under a subscription which is renewed annually.”
Officials with the National Weather Service said a storm-based warning not only combats apathy, but saves time and money.
“Social science research shows that people are more likely to take protective actions if they can personalize the risk and confirm the threat,” said Danielle Nagele, senior social science advisor for the National Weather Service who cited a specific study. “When warnings are specific about location, time and severity, recipients are more likely to believe that there is a real threat and to personalize the risk and thus establish protection motivation. In general, research has shown that the closer people are to the hazard, the more likely they are to respond and to do so quickly.”
In addition, focused storm warnings save money and time.
“Not only did this new geographic specificity leverage technological advances such as cell phones and social media, but it also reduced the number of people being alerted by these warnings,” Chris Maier, NWS National Warning Coordination Meteorologist, told the Hendersonian.
“One study estimates that storm-based warnings might save 66 million (working) hours actually spent sheltering a year with a value of $750 million,” said Maier, who in an email added the research she cited.
“Emergency managers make better decisions on what resources are required and where. Law enforcement and fire departments know which areas need to be put on alert. Schools and businesses more accurately determine whether or not they need to activate their tornado procedures and close operations. Other government agencies and customers, such as the FAA and airlines, are able to make better risk assessments. For example, airport operators ascertain whether or not they need to temporarily shut down an airport,” he said.
According to Keith Sherburn, an NWS severe weather program coordinator, storm-based warnings “enable more geographically specified, targeted alerts for end users through Wireless Emergency Alerts (WEAs).
“WEAs are sent to mobile devices for a variety of life-threatening, weather-related phenomena such as tornadoes, destructive severe thunderstorms, or considerable flash flooding, providing information on the threat and associated protective actions. Cell towers broadcast the WEAs to mobile devices within the threat area; therefore, storm-based warnings provide more precise WEAs and limit the ‘false alarm area’ of these alerts.”
Henderson County residents have been experiencing less interaction with storm sirens since December of 2024 when the weekly checks went from a very audible 60-seconds at noon on Fridays to a silent five to 10 seconds.
“This change was made in response to a number of complaints that the Friday tests were annoying residents,” Garrett said. “The 10-second test completes the necessary checks of each siren and registers the results in the computer system logs so we can monitor them and respond to error messages when they occur.
“As of March 1, we have also doubled our daily computerized tests of all the sirens from two per day to four. All negative test results are logged and immediately sent to EMA staff for investigation, mitigation and response,” he said.
An incident in late 2025 in which the sirens failed to sound as a severe storm was bearing down would not have been mitigated by longer or more frequent checks of the system, Garrett said.
“The issue in 2025 occurred due to a power failure at the transmitter site, not a particular siren or the controller of the sirens,” he said. “That transmitter was by-passed before the existing warning expired. The transmitter was re-activated at that time if another warning had been issued. The item causing the power failure was replaced the following week.”
COWS are designed, primarily, to alert people outside of approaching storms.
Garrett said there are a number of other ways to be notified.
“For indoor notification, please sign up for Hyper-Reach Public Alerts to notify you by voice, text and email,” he said. “Hyper-Reach is a free service provided through Henderson County Fiscal Court, the Henderson City Commission and Henderson County Emergency Management.
“People can also purchase a weather radio, download ‘Storm Shield’ or ‘Everything Weather’ apps on your mobile device,” he said. “There’s also the option of downloading the 14 First Alert or Eyewitness News WEHT WTVW apps. Citizens can sign up for KnowNow and/or check the Henderson EMA Facebook page,” he said.
For more information go to: https://www.hendersoncountyky.gov/m/newsflash/home/detail/63 https://www.hendersoncountyky.gov/537/Community-Outdoor-Warning-Sirens https://www.hendersoncountyky.gov/533/Hyper-Reach-Public-Alerting https://www.hendersoncountyky.gov/543/Know-Now
