Activating sirens for severe winds

[Jeff Duda]

I know this issue is nothing new and some counties in Iowa have had policies regarding this on and off for several years. Those in Polk County, Iowa (where Des Moines is) have recently made it well known that the sirens will be sounded if winds in excess of 70 mph are observed or forecast (via a severe thunderstorm warning text, for example). See http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=dmx&storyid=55459&source=0, specifically http://www.crh.noaa.gov/images/dmx/Outdoor-Warning-Siren-letter.pdf.

What do you think about this? I disagree with the idea because the county I grew up in (Linn County, Iowa) did not do this until I was 18 years old, then suddenly, they started doing it. I was taught as a youngster that the sirens meant a tornado was imminent, and I still think that way today. I doubt I'm alone in that mindset. To me, sounding the sirens for only a non-tornadic severe wind threat is like issuing a tornado warning that doesn't verify, i.e., another false alarm. The average citizen hardly needs another reason to ignore the sirens.

 

[Rob H]

Interesting topic - and one that I'm fairly passionate about. I grew up in Dakota County, MN and they sound the sirens for everything. Everyone I know that lives there hears the sirens and ignores them because of this. One of these days, a large tornado will bear down in Dakota County and I get the feeling that people won't react to the sirens.

Ultimately, the sirens are there to warn people and prevent injuries and death and I just haven't seen too many wind LSRs that have either. I might be wrong, but it doesn't seem to be the type of event that puts large amounts of people at risk or that catches people off guard. On the upside, I wonder if sirens for wind events would have fewer false alarms since they're usually on a larger scale than a tornado.

 

[Billy Mason]

I see absolutely nothing wrong with that. In fact, a lot of the cities in the DFW area will activate their sirens for one or more of the following conditions:

• A tornado warning issued by the National Weather Service
• Tornado or funnel cloud reported by a reliable source
• Sustained winds in excess of 70 mph
• Reports of hail larger than one inch
• Chemical spill emergency
• State or national emergency declared by the governor or president
• Other emergencies as appropriate

 

[cstrunk]

I would prefer that tornado sirens were for tornado warnings only. 70 MPH wind is strong, but I don't think it deserves a siren.

 

[Jayson Prentice]

The 70 mph threshold seems a bit on the low side for straight line winds. Yes the winds will likely cause damage, knocking around any loose objects and likely toppling a few weak trees and power poles. The threshold that some counties set at 80 mph was reasonable, given that there was good likelihood of those wind speeds occurring you are starting to get on the edge of seeing something very dangerous. Any widespread derecho event that has recorded winds speeds of 80+ mph I think warrants the sirens... Those wind speeds of only 70 mph can commonly be seen in warnings, thus the sirens may be sounded a little too often.

 

[MatthewCarman]

The 70 mph threshold seems a bit on the low side for straight line winds. Yes the winds will likely cause damage, knocking around any loose objects and likely toppling a few weak trees and power poles. The threshold that some counties set at 80 mph was reasonable, given that there was good likelihood of those wind speeds occurring you are starting to get on the edge of seeing something very dangerous. Any widespread derecho event that has recorded winds speeds of 80+ mph I think warrants the sirens... Those wind speeds of only 70 mph can commonly be seen in warnings, thus the sirens may be sounded a little too often.

I agree. While 70 MPH is strong winds I feel the sirens should only go off for 80 MPH winds or higher. 80 MPH winds with sustained winds over 70 MPH will do a lot more damage then 70 MPH winds with sustained winds in the 60's. Sunday morning for central Iowa I saw reports of a few gusts in the 70-75 MPH range but most of the winds were only in the 60-70 MPH range and did not do more than knocking down trees and power lines.

 

[jshields]

here in omaha they blow the sirens for over 75 mph winds. we just had them blown in our wind storm last wednesday! i believe omaha adopted that policy ironically after we had the two nighttime tornadoes in the millard area of omaha, and the sirens were blown really late, i.e. after the tornadoes were already doing damage. that same season later on, we had a severe squall line that blew through with winds up to 115 mph and thank god the sirens were blown then. i actually agree with the 75 mph limit. those winds are just as strong as a weak tornado, and can cause harm to life and property. better safe then sorry of course. the people who don't want to adhere to the sirens blowing, are the same people who prob wouldn't do anything if they were only being blown for tornadoes anyways

 

[Robert Dewey]

If there's substantial evidence that winds will gust >75MPH, I'm all for it. Sirens are geared more towards those who are out and about. Since some gusts fronts tend to outrun the precipitation area, it's possible you could be hit before you're even aware that a dangerous situation is approaching.

 

[James Hammett]

Here's another thread on the topic:

http://www.stormtrack.org/forum/showthread.php?t=16969

While it's technically true that outdoor warning systems are intended only for people who are outdoors and people should be getting their warnings from elsewhere we all know the reality is quite different. Once people catch wind that high winds also get the siren treatment, they will indeed be desensitized to warnings for tornadoes. While 70MPH winds are at the level of an EF0 tornado, most folks are likely only going to see 50-60mph gusts and that isn't at all comparable to a tornado which can ramp up its wind speeds to much, much higher levels.

The situation gets more complicated when the sirens sound at 3am and people have more of an excuse to be unaware of the weather situation. Is this just for wind or is this for a tornado and my NWR is broken? Confusion like this eats up warning lead time and puts people in danger. Derechos often come through overnight and who is going to be outside at 3am anyway?

 

[James Hammett]

i believe omaha adopted that policy ironically after we had the two nighttime tornadoes in the millard area of omaha, and the sirens were blown really late, i.e. after the tornadoes were already doing damage.

But shouldn't a tornado warning be issued in this case anyway? If you're going to issue a CYA warning that decision should be made on a case-by-case basis...not a criteria based solely on expected gusts. I know it's impossible to predict with 100% certainty but uncertain warning decisions are made all the time...and mistakes are sometimes made.

Another big event was the derecho with embedded tornadoes that went through Kansas City a couple years ago. I recall lots of "we had no warning!"'s after that one.

 

[Penny Lehner]

Well I will start off first by saying....they are NOT tornado sirens. They are civil warning sirens. Initially they were called civil defense sirens but now people think they should be used exclusively for a tornado. And yes, they should be used for high winds. If the winds are strong enough to take large branches off of trees, then people need to be warned. Not everyone is inside. I had my Mom in the basement Saturday night due to the high winds. (Big trees and huge picture windows...not a good combination during high wind events.)

I too call them tornado sirens but that is not what their sole purpose is. They are civil warning sirens.

 

[James Hammett]

If the winds are strong enough to take large branches off of trees, then people need to be warned. Not everyone is inside. I had my Mom in the basement Saturday night due to the high winds. (Big trees and huge picture windows...not a good combination during high wind events.)

I don't think anyone is arguing that outdoor warning systems should be used only for tornadoes simply because the public refers to them as "tornado sirens". There are psychological aspects to public warnings and I think that's what is being discussed here.

Even if the sirens don't sound people ARE still warned...through strongly worded Severe Thunderstorm Warnings, weather radio, media reporting, etc. It's your choice whether or not you head to the basement when a Severe Thunderstorm Warning comes through...whether or not the sirens sound.

 

[MatthewCarman]

Even if the sirens don't sound people ARE still warned...through strongly worded Severe Thunderstorm Warnings, weather radio, media reporting, etc. It's your choice whether or not you head to the basement when a Severe Thunderstorm Warning comes through...whether or not the sirens sound.

The people outside won't always get the warning that goes out to the TV's and Radios. It is for these people the sirens should be sounded if the winds are strong enough to injure some one.

 

[Justin Wiley]

Why not just sound the sirens for 58 mph winds then? Talk about confusion. A severe thunderstorm warning is issued for certain situations but then others involve sirens sounding. I personally think it's a bit over the top myself.

James brings up an interesting point. Would waking people up with sirens who are already inside at 3am absolutely necessary? The public already gets mad enough for tornado warnings at 3 am (I'm not arguing with this though).

I think 95% of America associates a wailing non-vehicle siren as a tornado siren. I think this would do more confusing than anything else.

 

[James Hammett]

The people outside won't always get the warning that goes out to the TV's and Radios.

Should we then sound the alarm for people caught outdoors in large hail as well? Seems more justified than sounding the alarm for someone outdoors at 3am with strong wind on the way.

It is for these people the sirens should be sounded if the winds are strong enough to injure some one.

I'm not totally opposed to non-tornado outdoor warnings but you have to draw the line somewhere and as you concurred the 70mph criteria is too low.