Created: 11/04/2009 7:28 PM KSTC45.com | Print Story By: Becky Nahm

Lakeville Tries to Solve Tornado Siren Mystery

Twice in the past five days, tornado sirens in Lakeville blared a warning on their own. Now authorities are trying to figure out the mystery of what triggered the sirens.

Friday night around 9 p.m. several sirens experienced what police called "false activations." They sounded without being activated by the Dakota County Communications Center.

A similar problem occurred Wednesday at 7:15 a.m. when at least one siren in the area of 165th Street and Jaguar Path went off.

Kathy Nygard heard the sirens both days.

Nygard said, "I was making coffee and I went for heaven's sake, what is going on?"

She wasn't alone. The communications center received 33 calls Friday night and more Wednesday morning.

Lakeville Police Chief Thomas Vonhof said technicians are working on the problem.

Vonhof said they know a random radio frequency is triggering the sirens. But they do not know its source.

There are several possibilities. Atmospheric conditions could be enabling a signal from another part of the country to set off these sirens. Interference from passing airplanes might be to blame, or it could be interference from FM radio or TV signals using the same bandwidth.

Vonhof said, "We are investigating and looking into it and I think we'll get to the cause of it, hopefully."

Until a cause is determined, the false alarms could continue.

Dakota County did test its sirens Wednesday at 1 p.m. as part of its regularly scheduled monthly test. All of the sirens worked properly.