I was surfing online and came across a few pictures of a Thunderbolt from the Southwestern Oklahoma town of Granite:
http://www.abandonedok.com/wp-content/u ... 29-LOW.jpg
http://pics4.city-data.com/cpicc/cfiles47525.jpg
From the pictures I have seen this appears to be the town's only siren. Seemed like a neat find so I thought I'd share it with everybody.