Background
Outdoor warning sirens are a tool used by emergency officials to warn the public of an immediate threat to life-safety from many types of severe weather threats.
Public Warning System
Outdoor warning sirens are just one element in an integrated public warning system that uses many methods to provide immediate, life-safety warning to the public as quickly as possible. Other elements of this integrated public warning system include the National Oceanic and Atmospheric Administration’s (NOAA) Weather Radio (NWR); broadcast radio, television and cable providers that use the Emergency Alert System (EAS); Wireless Emergency Alert (WEA) systems (cellular telephones); telephone notification services (Alert Iowa); and digital message boards along highways. No single piece of public warning technology is capable of alerting all people all the time. Having a variety of warning tools provides a means to have several methods to alert the public to severe weather.
Siren Capabilities
Outdoor warning sirens are quite simply tools to warn people who are outdoors to take immediate, potentially life-saving action by finding shelter from an imminent deadly threat.
Though some people who are very close to an outdoor warning siren may hear it while they are inside a building, the sirens are intended to warn those people who may be outside during a dangerous threat to seek shelter. People should understand that sirens are the last link in the warning chain, not the first.
People should take the time to check weather forecasts for the day and to be aware of their surroundings. People should also take responsibility to be personally prepared by purchasing weather radios or signing up for one of the alert services mentioned in this article and finding a safe shelter within a structure.
Outdoor Warning Siren Policy for Black Hawk County
Three types of violent weather events trigger siren activation:
- Tornadoes (NWS tornado warning and/or trained spotter reported)
- Extreme Winds (NWS measure or imminent at or above 70 MPH and /or reports of whole trees being blown down)
- Large Hail (NWS measured or imminent of 1.75” (golf ball sized or larger and /or reports of windows being broken by hail), hail this size also can cause bodily injury.
For more information on siren activation, weather preparedness or questions regarding this article please contact, Black Hawk County Emergency Management at (319) 291-4373.