I ran across this last night: http://n7twt.net/palo_verde_siren_test.html
A test of the Palo Verde Nuclear Generating Station ten mile radius EPZ siren test on November 13, 2013. These sirens are located in Tonopah, Arizona just West of Phoenix. While this is a system of A.T.I. sirens, us Arozona enthusiasts and collectors don't get to here siren systems (or any outdoor warning sirens for that mater) too often. They test this system only once per year. There are 48 sirens in this system. If you are a HAM radio operator this gives you a chance to help as well.