An Air Raid Siren Woke Me Up This Morning. . .

Air Raid Siren 121 on Burbank BlvdSeriously, at 6:30am approximately. I was ripped from my slumber more confused then annoyed. Trying to figure out what it was. Not a car alarm, no modern alarm at all, but the rolling wail of sirens past.  The only thing I could think of was the cold war era air raid sirens that have dotted the San Fernando Valley landscape.  It rang out again at approximately 10:30am.  We also remember hearing something last night at approximately 11pm.  I drove down to the nearest to have a look and snap this photo.  It looked just as derelict as always.  No sign of hooligans.  I may never have answers.  According to the internet this emergency system hasn’t been used since a test in the mid 80s.  Anyone else have a clue?

Interested in these things?  here is a great map:
http://wirechief.com/sirens/map.htm