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Dakota county OUTDOOR WARNING DEVICE (SIREN) POLICY - 2012

Background

From the early 50’s through the late 80’s the Outdoor Warning Devices were commonly known as “air raid sirens”. The siren systems were, in a large part originally developed as a response to the “Cold War” and the threat of a nuclear attack.  During that period of time, the National Weather Service (NWS) was responsible for activating the sirens, for the entire seven county Metro Region. The National Weather Service classified two types of storm warnings.

Those storm warnings were:

  1. Severe Thunderstorm Warning (based on a NWS advisory).
  2. Tornado Warning (as indicated by NWS radar).

The NWS would only activate the system for a Tornado warning. During that time period the cities of Burnsville, Apple Valley and Lakeville were hit by straight-line winds from a Severe Thunderstorm that caused numerous injuries and extensive damage.

In the late 80’s the Federal Government decided that the siren systems should be used for additional warnings and re-named them Outdoor Warning Devices. At about the same time the National Weather Service turned over responsibility for the actual activation of the system to each individual county. The Outdoor Warning Devices in Dakota County are designed to alert people who are outdoors (on golf courses, lakes, playgrounds, parks, ball field, etc.) and need to be warned of dangerous situations that are developing in the area.  Sirens in the Dakota County system include different style, sizes and configurations of outdoor warning devices. The sirens are owned and maintained by each city.  The dispatchers at the Dakota Communications Center (DCC) are responsible for activating the sirens.

In Dakota County, The current procedure allows cities to activate the system for a Severe Thunderstorm Warning issued by the NWS in addition to those alerts issued for a Tornado Warning. Activation of the system can also be triggered if a law enforcement officer advises the dispatcher to activate the system.

The reasons for including activation of the system for Severe Thunderstorm Warnings include:

  1. The potential danger and threat to pubic safety posed by a storm with 58 + MPH (shallow rooted trees pushed over) winds, large hail, lightning, and heavy rains.
  2. The use of Outdoor Warning Devicesis the most effective method of warning people who are outdoors.
  3. The number of mobile home residents in Dakota County.
  4. National Weather Service and local media are warning people the storms are severe and to seek shelter. The outdoor warning devices are another method of warning people.
  5. The possibility of widespread electrical power outages during severe weather that would make the sirens inoperable. Sirens need to be sounded before severe weather strikes an area.  TORNADOES USUALLY FORM ON THE BACKSIDE OF SEVERE THUNDERSTORMS, BEHIND THE HIGH WINDS, LIGHTNING, RAIN AND HAIL.

 

PROCEDURES FOR ACTIVATION

Actions to be taken.

A. Warning received for Weather Related Emergency from National Weather Service, law enforcement.

  1. Advise the police agencies in the effected cities why the sirens will be activated.
  2. Load the system with the sirens in the effected cities and send signal.
  3. Notify the National Weather Service of the sounding and the reason (Severe Thunderstorm, Funnel aloft, Tornado) and request activation of the Emergency Alert System (EAS) and the KEC – 65 Weather Alert Radio.

B.      Warning of a Hazardous Materials Incident.

  1. Obtain accurate description of area to be evacuated and, if appropriate, evacuation route(s).
  2. Activate the community notification system for the impacted area
  3. Send a teletype of the incident to surrounding law enforcement agencies including law enforcement agencies in neighboring counties tha1t may potentially be impacted by the Hazardous Material Incident.
  4. The sirens in the Emergency Planning Zone for the Prairie Island Nuclear Power Plant (PINGP) will be the exception. Federal Regulations require an activation those sirens in the event of Protective Action Recommendations (PAR) are issued

 
C.      Notification of Emergency Management Personnel upon Siren Activation.

  1. When practical, load the community notification system with the emergency management personnel associated with the affected cities and the County Emergency Preparedness Coordinator, send a message stating siren activation has occurred and the reason why.

 

II.       Testing Procedures

State policy is that counties and municipalities test their outdoor warning devices at 1300 hours the first Wednesday of each month. Counties and municipalities are encouraged to make advance announcements of each test through local radio, television, and newspapers.

A.      At 1300 on the first Wednesday of each month the Dakota Communication Center (Warning Point) will take the following actions:

  1. Be prepared to receive and acknowledge the TEST warning message from the State Patrol.
  2. Load the system and send the (test) ALERT signal. This is a steady tone for a period of three minutes.

 

Wednesday, April 18, 2012

 

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