The sirens you hear this morning are only a test.

At 10 a.m., Hall County's 911/Central Communications Center will hold its quarterly test of the severe weather warning sirens located around the county.

The sirens, which are audible from a mile away, are used to alert people that a tornado has been spotted.

"Every February, May, August and November, the wail sounds for about three minutes," said Leigh Stallings-Jarrell, the center's operations manager. "These are designed for outdoor notification."

The siren system is tested silently every morning at 9 a.m.

"We do a check to make sure each siren is functional," she said. "We get a report here at the center."

Sound tests will not be conducted if there is a severe weather watch or warning in effect for Hall County.

Other than previously announced tests, all sirens should be considered to be an actual tornado warning, and people should take shelter immediately, she said.

There are 16 tornado sirens stationed at various sites around the county, from the Hall County Fire Station in Clermont to Spout Springs Elementary School in Flowery Branch. Hall County's website features a map of the weather siren locations.

"Not too long ago, on that stormy Wednesday, we had severe storms right around midnight," Stallings-Jarrell said. "We sounded the sirens for the tornado warning there in Clermont."

In 1998, a tornado tore through the North Hall area. It left 12 people dead, around 100 families without homes and caused some $15 million in losses, including damage to two schools in its path.

Hall County received a grant for the sirens shortly after the tornado.

The sirens are sounded any time the National Weather Service issues a tornado warning or there is a confirmed sighting of a funnel cloud by law enforcement personnel.

During storms in 2008, the county was able to sound the tornado sirens ahead of an alert from the weather service when an Oakwood police officer spotted a tornado and notified the 911 center.