I guess the city goofed up on this test. They normally sound the siren for a minute of alert, then stop for a few seconds, then do a minute of attack. Today they did the alert... no other sirens were heard. We waited about 10 minutes, then decided to leave... As we were leaving it sounded the alert again. Thinking they goofed up and did the full test, the attack signal sounded and all the sirens in town went off this time. This is why tests are important.
http://www.youtube.com/watch?v=tFUv3Qckhus