Here in the US they are called "civil defense sirens" and depending on the area and the tones that they emit they can indicate any number of threats to the public. Of course their first use was during WWII to warn of air raids and then nuclear attack during the cold war. Now they are probably best known as "tornado sirens" (at least here in the midwest) but the ones in my city can also be activated with a different tone to warn of a breach in the upstream dam which would indicate that a flood is imminent in the lower lying parts of town.
There was some discussion about them on the talk-us mailing list back in May: http://lists.openstreetmap.org/pipermail/talk-us/2010-May/003230.html Toby On Sun, Jun 27, 2010 at 7:17 PM, John Smith <deltafoxtrot...@gmail.com> wrote: > On 28 June 2010 01:38, Johnny Rose Carlsen <o...@wenix.dk> wrote: >> Hi Alan, >> >> It's a siren, they are pretty common in Denmark. >> >> In Denmark they are used as part of a general warning system, I don't >> know the use of the sirens in your area. > > Similar things exist in various places for tornado warnings in the US... > > http://www.ci.sand-springs.ok.us/news-entry.php?cat=1063&id=1086 > > _______________________________________________ > talk mailing list > talk@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk > _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
