posted on Dec, 16 2012 @ 07:41 PM
At first I thought it was just an industrial motor somewhere in the neighbourhood, whining. I live close to Trafford Park, and hear motors whining
like that a lot. A constant high pitch squeal. But then, it tailed off, and is definitely a siren of some kind.
Its not an air-raid siren, they tend to be two tone, alternating between the two tones.
Tornado sirens tend to be modified air-raid sirens, the ones that I've heard anyway.
I wonder, if you live near a port, chemical refinery or military base of some form, and they were running their alarm sirens. All 3 types of facility
have to have powerful sirens to alert the neighbourhood of possible danger, by law. Their sirens also have to be tested biannually, but siren tests
are usually published in the local press a month beforehand so as to stop people panicing.