"Recently, the City of Joplin upgraded its outdoor warning sirens. In review, the sirens are outdoor warning devices that are used to alert people who are out of doors to go indoors and seek shelter. In decades past these sirens were installed to warn citizens in the event of an attack on our nation by a foreign power. These days, outdoor sirens are used to warn of an impending locally severe weather event. Some people have asked, "During what kind of weather event are the sirens sounded?" The answer is, simply stated, "a high speed wind event". Obviously this needs further explanation.
Some may think of sirens as necessary just for tornado warnings, but it’s important to note that high speed winds can be comparable to, or faster than, winds produced by a low-rated tornado. Tornados range in size, based on wind speed, from an EF0 (65 miles per hour minimum) to an EF5 (200-plus MPH). An EF0 tornado, once on the ground, can be as small as 100 feet in width. Everyone expects the sirens to be activated for any tornado, even a "small" one that is much less than a city block wide.
In comparison, a severe thunderstorm is capable of producing winds of 70 to 80 MPH (or greater!), and can cover a width of several miles, which can encompass the entire City at some points. It is imperative to sound the sirens for this type of high speed wind activity as well, due to the potential for both property damage and threat to lives.
This analogy is one that City officials reviewed when establishing the basis for the storm siren policy (see below). The City of Joplin activates the sirens for ANY wind event of sufficient speed, regardless of its label - tornado, high winds, straight line winds, or a derecho (a widespread, long-lived, straight-line windstorm that is associated with a fast-moving band of severe thunderstorms). All winds above certain speeds are potentially dangerous, and the City’s policy recognizes this fact: Outdoor sirens will be sounded to warn our citizens who are out of doors to go indoors and seek shelter from the wind. Please see below for specific information on the siren policy.
The City of Joplin will activate outdoor warning sirens when any of the following severe weather conditions exists:
Storm Siren Activation Policy
Storm Sirens shall be activated when:
The National Weather Service issues a TORNADO WARNING, OR a trained spotter reports a tornado:
In Jasper County, Missouri; Newton County, Missouri; or Cherokee County, Kansas
AND the tornado path includes the City of Joplin
Or the National Weather Service reports a storm system producing wind speeds of 75 MPH or greater, AND the storm path includes the City of Joplin
Storm Siren Audible Testing
Storm sirens will be audibly tested on the first Monday of each month at 1000 hrs.
The monthly audible siren test will last for one minute.
Audible Testing will NOT take place:
During times when thunderstorms are predicted in the area, or are actually in the area
During freezing weather conditions
If the sirens are not audibly tested due to either of the above situations, the sirens will be audibly tested at the next regularly scheduled date and time. There will be no "make-up" audible test.
Siren repair - audible testing will only occur following a minimal time period needed to notify the media and public that a siren will be audibly tested. This is usually 24 hours' notice.
Siren Activation to Warn of An Actual Severe Weather Event
The sirens sound a steady tone for three minutes. See the YouTube Video link below for an example.
The sounding of the sirens means "Move Inside Immediately and Seek Cover!"
Each siren activation indicates a tornado/high speed wind event is approaching the City.
Joplin does not sound an all-clear siren. Please listen to your NOAA Weather Radio or other info source."
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