By BRAD GASKINS / Staff Writer

The city of Calera is updating its severe weather sirens.

The upgrades began Feb. 21 and should be complete either later this week or early next week, according to Calera Fire Department Dep. Chief Hilton Shirey.

The sirens will not work while the upgrade is underway.

Calera’s six sirens remain in place, but the electrical boards from inside the sirens are being updated at a Connecticut-based business. The company is changing radio frequencies to narrow band. The FCC has mandated all sirens make the switch by 2013.

Once the electric boards are put back in the sirens, the sirens will have a “talk back” feature. The sirens will send one-way messages to city officials, letting them know the siren is working and hasn’t been tampered with.

“It’s a fail safe way for us to know if there’s a problem with a siren,” Shirey said.

The Emergency Management Agency is coming out with a new program that will use what’s known as a polygon system, Shirey said. When the National Weather Service issues a severe weather alert, if the city of Calera lands within the polygon then the sirens will go off.

If a tornado warning is issued for North Shelby, for example, then sirens in Calera will not sound, Shirey said.

“It sort of takes out the ‘cry wolf’ deal,” Shirey said.

In other words, he added, when the sirens in Calera go off, there is bad weather approaching, as opposed to the current system where there could be bad weather 30 miles away but clear skies in Calera.

When the upgraded sirens sound, Shirey said, residents can “take it to the bank” that severe weather is approaching the city.