Outdoor warning sirens - part 3: the warning process and future of severe weather warning systems

This part of the series is a long time coming, but here it is!

In the first two posts of this series on outdoor warning sirens, we examined the role of the Emergency Management Agency during severe weather (including the activation of warning sirens) and the role of outdoor warning sirens themselves, which was to warn people who were outdoors of adverse weather.  In this post, the final in our 3-part series, we take a look at the future with regards to dissemination of severe weather warnings.

Background on the current warning process

In 2007, the NWS changed policy with regards to issuance of Tornado, Severe Thunderstorm, and Flash Flood Warnings to one based on the actual area threatened versus alerting entire counties. The NWS draws storm-based warnings, or "polygons," to highlight the expected path of the storm, with little regard for political boundaries (see the example from March 15, 2012 below).  This policy change had several intentions, one of which was to limit the area being warned, thereby hopefully reducing the perceived false alarm rate created by warning an area that the NWS is fairly certain will not be affected.


A Severe Thunderstorm Warning polygon ("storm-based warning") that identifies a small section of eastern Fayette Co. and a larger portion of Hardeman Co. as having a threat of large hail and damaging wind.  There is no threat of severe weather in Moscow or Middleton, even though there is in other parts of their counties.

Unfortunately, some 5 years after changing to storm-based warnings, NOAA Weather Radios, many outdoor warning siren systems, and even some local broadcaster's warning plotting software - the top 3 ways that citizens get severe weather information - still alert based on the COUNTIES affected, rather than the actual AREA affected. In the example above, the storms are moving northeast and, based on the yellow polygon, there is no threat to Moscow, Macon, or Middleton.  However, for those with Weather Radios in those locations, the alert tone would sound for all three towns.

Another example is below - this one even closer to home for many of you.  A Tornado Warning was issued shortly after 10pm on January 22, 2012 for southern Shelby County and northern DeSoto County. A squall line (not depicted) was approaching the river and a possible tornado was detected in the portion of the line that would affect the areas inside the red box.  Sirens sounded and weather radios alerted across Shelby County (excluding DeSoto County for this example).  Except for the southern part of the city and the eastern suburbs, there was no imminent threat from a tornado.  It could be said that although the NWS intended to only warn 242 sq. mi. of Shelby County, the sirens and weather radios ended up warning 754.5 sq. mi. or more than three times the area.  (In this example, there was sporadic wind damage reported, including a 105 mph gust that lifted a large roof from a commercial structure, all within the confines of the warned area.)

Outdoor warning sirens and the polygon warning

Now that the warning process is better defined, what is the future of weather warning dissemination?  Perhaps from these examples you can already start to see it: storm-based warning dissemination, rather than county-based.  While NOAA Weather Radio and some progressive county governments are beginning to make strides in this area, it will be some time before these systems are fully taking advantage of the benefits of the current storm-based warning program.

In Shelby County, TN, EMA Director Bob Nations indicates that they are "taking a serious look at new technology" and "exploring all the options" as they work towards system upgrades mandated by the Federal Communications Commission (FCC).  The FCC program, called "narrowbanding," opens up additional radio frequencies by essentially squeezing all of the current frequencies closer together in the radio spectrum. Narrowbanding will require a significant purchase of new hardware or upgrades to current infrastructure to meet a federally mandated January 1, 2013 deadline.  How does this affect the siren program?  The sirens are activated by radio frequencies that will change under the  narrowbanding program.

Part of the infrastructure upgrade will include new siren controllers on 111 warning sirens under the purview of the City of Memphis, which will be replaced with equipment that allows individual sirens to be sounded should a change in siren policy be made.  In addition to hardware, new storm-based warning software would also be required to activate individual, or banks, of sirens.  Nations is quick to point out that, while a change to siren policy might be possible with the new infrastructure, there would have to be agreement from policymakers who may not be willing to take the risk of storms remaining within the warned area.  Any changes to public policy will require the approval of those who write the policy.  Due to potential liability issues, any change to the current methodology of warning the entire county "would have to work every time," according to Nations.

So while (and until) the infrastructure upgrade and public policy process plays out (should there be a decision to move in that direction), citizens are strongly encouraged to consider all means of protecting themselves in the event of severe weather.  As discussed in part 2 of this blog series, outdoor warning sirens are not the "end all, be all" and are simply not designed to alert you if you are anywhere but outdoors, no matter what strategy is employed to sound them.

The future of weather warning systems

The best solution is that we move to faster-pace, more technological solutions that are available today. With the preponderance of smartphones and the capability of these devices to use GPS to determine your precise location,  it's no wonder their worth in targeted warning information is being utilized more and more.  There are several mobile apps that are available to warn you, in your specific location, to the threat of impending weather.  Of course, we highly recommend ours, but any will likely fit the bill depending on the features you are looking for.

The MemphisWeather.net app for Android and iPhone includes StormWatch+, a push notification system that will warn the user of severe weather watches and warnings that are issued for 2 pinpoint locations of their choosing.  It includes an audio alert that is loud enough to wake you up at night provided the phone is nearby and not silenced.  There are other services available as well, including some phone services that will call your registered numbers should severe weather threaten.

It is vitally important that you have multiple ways of receiving severe weather information, for your location if possible (or for your county if not), that will alert you at any time of day or night.  Outdoor sirens are one way, but they CANNOT be the only way.  NOAA Weather Radio is highly recommended as the baseline, but for even more pinpoint warnings that take advantage of the storm-based warnings issued by the NWS, you should add another service like StormWatch+ to your severe weather toolkit.  Severe weather can strike in any month and at any time of the day in the Mid-South.  "An ounce of prevention is worth a pound of cure."

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or follow us on Facebook or Twitter.

Outdoor warning sirens - part 2: the role of outdoor warning sirens

In part 1 of this MWN Blog series on outdoor warning sirens, we examined the role of the Memphis/Shelby County Emergency Management Agency (MSCEMA) with respect to severe weather, specifically the process by which outdoor sirens are sounded.  In it, you learned that the EMA is responsible for sounding all sirens in Shelby County except those in Bartlett, Collierville, and Germantown, who activate their own sirens. In part 2, we will focus on the purpose of the sirens, what they are intended to do, and more importantly, what they are NOT intended to do.

To recap, outdoor warning sirens are sounded continuously countywide whenever any portion of the county is included in a Tornado Warning issued by the National Weather Service (NWS). These outdoor warning sirens are NOT referred to strictly as tornado sirens for a reason: it is not fully descriptive of the mission they serve. From the MSCEMA website (http://www.mscema.org - emphasis added): "[Outdoor warning] sirens are designed to be an early warning device primarily for persons who are outside away from the television and/or radio."

As stated above and repeated many times by MemphisWeather.net, these are OUTDOOR sirens. They can be extremely useful if one is working or recreating outside and severe weather threatens. When sirens sound, you should seek out additional information on the threat.  This can be done in a number of ways, but the most common are to tune into local radio or television, check local weather websites or properly-equipped smartphone apps, and/or turn on NOAA Weather Radio (which should have also sounded an alarm when the sirens sounded).  If none of these additional information sources is available, you should take adequate cover until the sirens cease.

Photo credit: MWN
Smithville, MS warning siren

Sirens are NOT designed to A) wake you up at night, especially if storms are in progress with wind and rain creating additional noise or you are a heavy sleeper; B) alert you if you are indoors, especially in newer, more energy-efficient, and better-insulated homes with additional electronic noise (like air conditioners running, music playing, or television on); or C) reach every square mile of the county.  In fact, even outside, environmental factors such as the direction and speed of the wind, relative humidity, and air stability can affect where sirens are heard on any given day.

The bottom line is this: sirens are designed to alert those outdoors to the threat of severe weather and encourage them to seek additional information.  Do NOT call local authorities, including the EMA, if you aren't woken up by a siren or you didn't hear it inside, UNLESS you are fairly certain that a nearby siren that you have heard under those circumstances before is not operating properly (i.e., fails to sound).  Click here for a list of all sirens and the person to contact in case of siren failure ONLY.

In the third installment of this series, we will examine the future of warning technology - from sirens to smartphone apps - in an age of polygon warnings.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Outdoor warning sirens - part 1: the role of the EMA during severe weather

Recently I had the honor and pleasure of sitting down with several individuals from the Memphis/Shelby County Emergency Management Agency (MSCEMA), including Mr. Bob Nations, Director; Mr. Levell Blanchard, Deputy Director; Mr. Tommy Thompson, Outdoor Warning Siren Coordinator; and Mr. Keith Butler, Dispatcher and "technical guy" for the EMA's many electronics and communications systems.  I also was fortunate to tour the EMA's Emergency Operations Center in Midtown. The purpose of the meeting was to discuss the outdoor warning siren system in Shelby County, learn more about how their systems and processes work during severe weather, and perhaps find out if any changes to the warning process were in the works.  I came away impressed with both the responsibility and recent accomplishments of the EMA personnel.

This is the first in a 3-part blog series on the outdoor warning sirens in Shelby County.  This first entry examines the role of the EMA during severe weather, including the sounding of the sirens.  The second installment will focus on the intent of outdoor warning sirens, what they are designed to do, and NOT to do. The answers may surprise you. We'll conclude with a look at the future of warning technology, including sirens, in part 3.

Photo credit:
MSCEMA.org

One of the most visible (or audible perhaps) roles of the EMA is the sounding of outdoor warning sirens. I've discussed the policy of sounding the sirens previously on this blog, but the bottom line is this: currently, all sirens in Shelby County sound continuously throughout the duration of a Tornado Warning if any part of Shelby County is included in a National Weather Service-issued Tornado Warning.  That means if Millington is under a tornado warning, Collierville's sirens sound (more on how this works below).  Click here for a map of siren locations in Shelby County or click here for a list of all sirens..

Though the siren system was originally designed to warn the public of air raids during World War II, then nuclear fallout during the Cold War, the practice of using sirens to warn of severe weather dates back decades, well before the NWS began issuing polygon warnings that didn't encompass entire counties. That NWS policy change occurred in 2007.

The EMA Emergency Operations Center (EOC) is staffed by dispatchers around-the-clock, handling all sorts of calls for emergency response.  Their busiest period is typically during severe weather. In the EOC, a computer running weather messaging software is constantly ingesting bulletins from the Memphis NWS office via satellite (with internet backup) and processing them for any watches and warnings.  (Backup systems are also in place in case of a failure of the primary computer, including Weather Radio, statewide emergency communications, and local broadcast television.)  In the event of a watch or warning, a pop-up on the dispatcher's terminal immediately displays the text of the alert.

Photo credit: metrolic.com

If the alert received by the dispatcher is a Tornado Warning for any part of Shelby County, the dispatcher will then activate the sirens throughout Shelby County - except Bartlett, Collierville, and Germantown - using two different systems.  The three municipalities named are responsible for activation of the sirens in their own jurisdictions. Telephone calls are placed from EMA to dispatchers in each of these three suburban cities to make them aware of the warning.  Bartlett, Collierville, and Germantown will typically also sound their sirens based on the information they receive.  The sirens sound countywide until the expiration time of the warning or the cancellation of it, should the NWS cancel the warning prior to the original expiration time.  All of Shelby County must be clear of any Tornado Warnings before the sirens will be shut off.

Stay with us later this week as we examine the use of outdoor sirens in part 2 of this 3-part blog series.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.