Why don't tornado warning sirens sound continuously?
May 1, 2012 3:09 PM   Subscribe

Why don't tornado warning sirens sound continuously?

I know that tornado warning sirens sound for several minutes each time they are activated. When the sirens stop, it is NOT an indication the threat of a tornado has passed. There is no "all clear" signal. But a lot of people who didn't grow up around tornadoes think that when the siren stops going off, the danger is over. If it is easily misunderstood, why wouldn't they just leave the siren on constantly until the tornado warning is over?
posted by madscientist01 to Science & Nature (17 answers total) 2 users marked this as a favorite
As someone who used to live a few hundred feet from one of those sirens, I would say: hearing loss and insanity?
posted by goethean at 3:14 PM on May 1, 2012 [4 favorites]

Response by poster: I thought someone might comment on how annoying the sound is... if you're in your basement, is it really that loud?
posted by madscientist01 at 3:25 PM on May 1, 2012

If they don't turn them off after a few minutes, the otherworldly wailing will wake the souls of the damned who will sweep over the land in a tide of longing and despair, mercilessly reaping the very sanity of the living like so much wheat before the scythe.

That and, tornado sirens are fucking loud and nobody wants to listen to that for hours on end. After a few minutes everybody with any sense will be cowering safely in their basements with the radio, if only because of the godawful noise. Mission accomplished.
posted by Scientist at 3:26 PM on May 1, 2012 [7 favorites]

YES they are that loud. There was one right next to my grade school, and even in the school basement (which was a designated fallout shelter) it was extremely loud.

When I grew up in Alabama I was taught that when you heard the siren, you were to head underground and turn on your weather radio. The siren tells you when to batten down; the radio tells you when it's okay to leave.
posted by ocherdraco at 3:28 PM on May 1, 2012 [1 favorite]

Not everybody has a basement. If you are in your inner hallway, or worse if you live in a trailer and thus are spending the tornado warning in a ditch, it is really, really loud.
posted by hydropsyche at 3:33 PM on May 1, 2012 [2 favorites]

Around here the sirens are on as long as there is a tornado warning, and they turn off once the warning has been lifted. It's very useful because of the consistency.
posted by michaelh at 3:47 PM on May 1, 2012

I think the actual noise of the sirens could interfere with communications of emergency services. Even if it's not a tornado, there still might be someone trying to call 911 because their house is on fire and it's a real problem if neither party can hear the other.
posted by A Terrible Llama at 3:53 PM on May 1, 2012

I had always assumed it was because people tend to pay more attention to intermittent sounds. And when you're in the bathtub under a mattress and kind of straining to hear it anyway over the wind and rain, the sound can turn into background noise. I have been all "hey, did they stop, is- oh, no, there they are" myself a few times.

Where I've lived, the sirens are a fair distance away and rotate, so the Dopplering serves a similar purpose. I can't even imagine being right next to one of those things, you'd need it to shut off to communicate at all, I'd think.
posted by Lyn Never at 4:01 PM on May 1, 2012 [1 favorite]

I live a block away from the siren. They are intermittent so that I do not poke my earballs out.

The sirens serve as the warning to take cover. They are not meant to let you know when the danger has passed...or at least that's what I was taught. You're supposed to pay attention to the radio for the all clear.

The sirens are super loud whether I'm on the second floor or in the basement. My house was built in the late 1800's so it doesn't have optimal sound proofing, windows or anything, really.
posted by fluffy battle kitten at 4:30 PM on May 1, 2012

...if you're in your basement, is it really that loud?
Basements aren't totally ubiquitous, even in the midwest. I live in the Indiana end of tornado alley and no-one in my neighborhood of several hundred homes has a basement. Ditto for the two similar neighborhood down the road from us. And we're all out in the country.

Anyway...a continuous siren would truly become insanely aggravating.
posted by Thorzdad at 4:38 PM on May 1, 2012

Because the people who live in tornado country all vote, and the people who decide on how the sirens operate depend on elections for their jobs. ;)

In some places there's a distinct "all clear" siren pattern to go along with the radio announcement.
posted by SMPA at 6:08 PM on May 1, 2012

Response by poster: Interesting perspective. I guess I've never lived close enough to the siren to find it aggravating. I was amazed today (during a tornado warning) to see people going back to their routine because "the siren stopped going off" and got to thinking about why that happens...
posted by madscientist01 at 6:24 PM on May 1, 2012

When I lived in Iowa, the sirens sounded again (briefly) when all was clear, so they didn't need to keep it going in between.

Also keep in mind that people are stupid and ignore the sirens. So I wouldn't assume that the people carrying on during the warning today really thought the tornado danger had already passed.
posted by parkerjackson at 6:50 PM on May 1, 2012

1) Tornado siren normally sounds continuously until all clear.

2) Tornado siren is sounding when it gets destroyed by a tornado.

3) Tornado slays everyone as they emerge from the basement.

(I have no idea if this is really the thinking, but it would be Alanis-Morissette-ironic, don't you think?)
posted by BrashTech at 7:20 PM on May 1, 2012 [1 favorite]

Holy hell. The one time I ever lucid dreamed, the sirens went off on the next block (power was cut, and they automatically switched to batteries and went off), I knew, in my dream, that it was my real-life self hearing the sirens, and that it had no bearing, and that the dream was really awesome, and it *still* woke me up. So yeah, they're effin' annoying at close range.
posted by notsnot at 7:49 PM on May 1, 2012

Tornado sirens aren't the warning itself. They are the announcement that there is a warning being transmitted through regular channels, so you should go to your TV, internet, radio, etc., to hear what the actual warning is. They are primarily for people who are outdoors and unable to receive the warning, or people who do not have their TVs or radios on, so that they know to get someplace safe and try to find out what the real warning is through normal communication channels. They are not a message of tornado danger unto themselves.
posted by AzraelBrown at 7:51 PM on May 1, 2012 [1 favorite]

In my experience, the sirens alert you that you should be checking the news/radio/weather dude's twitter account. The real tornado warning is an insane drop in air pressure and a palpable sense of terror.
posted by yeahyeahyeahwhoo at 11:49 AM on May 2, 2012 [1 favorite]

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