Sirens Giving Way to Emergency Alert Systems


Emergency notification systems historically serve to provide warnings about emerging threats to give people enough time to protect themselves and the people they love. 

In the United States and in many places across the world sirens became commonplace following World War II. In 1970 these same sirens were given a second responsibility, to warn people of tornadoes. And once the Cold War ended, sirens were primarily used for tornado warnings.

Technology has changed a lot since 1970. 

Increasingly in the past decade, we are seeing more and more emergency preparedness experts warn that outdoor warning sirens are becoming obsolete. We are also seeing a pattern of counties that are retiring their outdoor sirens (even in places like Oklahoma where sirens are used widely across the state) and moving toward more modern ways of weather and other emergency notifications, such as Hyper-Reach, which combines text messages, voice calls and email with Wireless Emergency Alerts, smartphone apps and even advanced communication tools, such as browser alerts and smart speakers.

This trend is not limited to the United States. A recent article in CNN  profiles France, which is putting a WEA-like system in place. Referring to sirens, an official in Normandy noted, “We can’t manage 21st century crises with a 20th century tool.”

Earlier this year, Mobile County Alabama announced that their outdoor warning sirens will not be repaired or replaced and the system will cease operating this year. The county is strongly encouraging their citizens to engage more precise and efficient means of receiving location-based emergency alerts Mobile County to phase out outdoor warning sirens | WPMI (

Mobile County’s oldest outdoor warning siren has been in service since 1954 and the newest since 2016. Four of the outdoor warning sirens became operational in the 1950s and most are more than 20 years old. 

“Spending an estimated $15 million to update a system established around the time of World War II is not an effective use of resources, particularly when wireless emergency alerts, smartphone apps and weather radios provide faster, more location-pinpointed information,” said Mobile County Emergency Management Agency Deputy Director Mike Evans, who coordinated the cost-benefit analysis.

While sirens will continue to be used in many areas as an important method of outdoor notification, there are benefits of using a MNS in conjunction with outdoor sirens.  Limitations of sirens include:  

  • Sirens tell us something is happening, but not what. Emergency notifications give specific details that sirens cannot relay. 
  • Although some people may be able to hear these sirens inside of their homes, sirens may not be loud enough to wake people who are sleeping or be heard in all circumstances.
  • Not all areas of an alert area are, or ever could be, covered by outdoor warning sirens. Most sirens have a coverage area of between 2/3rd and 3/4ths of a mile radius and area topography prevents these from being an effective warning system for outlying areas, which is why they are found in more populated areas.

By comparison, emergency alert systems can deliver specific, targeted information that reaches people effectively.  As John Harsh, Emergency Management Director, Morrow County OH told us, 

“We’ve found that when severe weather alerts come through, Hyper-Reach has sent a notification up to a minute and a half faster than we can even get the warning sirens going and people are already in their safe space.”   

With severe weather events and other emergency situations increasing in frequency and severity, we’re not suggesting that anyone give up the tools they have available to alert the public. So enhancing a  working siren system with emergency alerts makes sense to us. But since resources will always be limited, if a county has to choose between a mass notification system and a siren system, we think the choice is obvious.


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