Ann Arbor Times

Testing of the 16 warning sirens throughout the city will begin on Thursday, January 26 in advance of planned Preventative Maintenance on the system. The testing is necessary to determine the individual site conditions, allowing the vendor to be prepared to address any issues identified during the testing. 

The testing will consist of a “Growl Test” at each siren. The siren will rotate for 30 seconds without sound, stop, and then do a limited volume audible blow that lasts 4 to 8 seconds. The sirens will be tested individually, not all at the same time.  

Following the initial “Growl Test," each siren must be tested again during the Preventative Maintenance visit to each siren, which will begin on Monday, January 30. 

Original source can be found here.