The tornadoes that devastated Tennessee this week hit in in the middle of the night, while most people were sleeping.
Many people have been asking, especially those who have moved here from other areas, why are there no tornado sirens in Knoxville and many East Tennessee communities.
It comes down to effectiveness and cost
The big factor is that most communities have determined that sirens are just not the most effective way to reach the most people in an emergency, according to Colin F. Ickes, Director of the Knoxville-Knox County Emergency Management Agency.
"Sirens are limited in their effectiveness since they are intended only to warn people who are outdoors that they need to take shelter. They don’t work well to warn people who are inside their homes. If you live very close to a siren you may be able to hear it inside, but even if you’re close it’s unlikely that you’ll hear it if you are watching TV, listening to the radio or sleeping," Ickes told 10News in an email.
They are also very expensive. Sirens typically cost $25 to $40 thousand dollars each.
If you wanted to cover Knox County effectively, Ickes said, you'd likely need a couple hundred of them. That could add up to almost $10 million dollars plus the costs of ongoing maintenance and operations.
In addition, the terrain likely factors in. Experts have said in the past that the mountains and ridges of East Tennessee would block the sounds of the sirens from reaching very far, so you would need more of them.
In areas where the terrain is flat and open, the sounds of a siren can travel a much greater distance.
So what should you do?
Ickes said that it would be much more effective if everyone had a weather radio in their home.
You could also sign up for local emergency alerts. Knox County has an emergency notification system you can sight up for here.
In addition, you can sign up for the WBIR News App. You can activate weather alerts in your area that will send you push notifications when there's an emergency situation.