Mayor / City Council
Boards / Commissions
Permits / Inspections -
Minutes / Agendas / Calendar
Notice to Bidders
Upcoming Residential Plats
WATCH City Council Meetings
WATCH Planning and Zoning Meetings
Metro Home Improvement Program
Property Tax Graph
Home Base Grimes, Iowa
Parks and Recreation
Adult & Senior Programs
Parks and Rec Staff
Grimes Community Complex
Grimes Heritage Museum
GCC Facility Schedule- Batting Cage
GCC Facility Schedule- Gym
Ball Field Rental Rates and Info
Grimes Sports Complex
Park Board Agendas/Minutes
Recreational Club Links
Special Community Events
Register Online Here- NEW!
Property Maintenance Information
Trash / Recycling
Permits / Inspections
Dog and Cat Licenses
Maps / Addressing
You are here:
Outdoor Warning Siren Frequently Asked Questions (FAQ)
What do the guidelines say?
Under the Polk County / Des Moines Metro Area outdoor warning system guidelines, sirens will be sounded for:
Severe Thunderstorms with winds occurring / forecast to be 70 mph or greater
The sirens may be sounded multiple times during the threat. There will be no "all clear" signal for the sirens.
What should I do when I hear the sirens?
Go inside to the lowest level, most-interior room of the structure and tune to NOAA All-Hazards Radio or the local media for more detailed information on the storm's location, timing, and intensity.
When are the sirens tested?
Sirens will be tested on the first Saturday of each month at noon. If actual severe weather threatens that day, the test will be delayed until the next monthly scheduled test. A "growl" test may be conducted on the third Saturday of the month. A "growl" test activates the system without a full audible alert of the system. Sirens may not be tested from December through February when ice and cold temperatures may damage the system.
Why can't I hear the sirens in my house?
Sirens are an outdoor warning system designed only to alert those who are outside that something dangerous is approaching.
Why don't outdoor warning sirens sound an all-clear signal?
People should be indoors and monitoring local media or NOAA All-Hazards Radio for updates on the storm.
How often can I expect the sirens to sound for severe weather?
On average, the Polk County / Des Moines Metro Area experiences approximately 5-15 storms each year that meet the siren guidelines.
Why were the guidelines developed?
When life-threatening weather is approaching, minutes or even seconds could make a difference. If people are unsure or confused about an alert, they may not respond quickly or appropriately. By adopting common oudoor warning system guidelines, confusion will be minimized, response time reduced, and lives will be saved.
How were the guidelines developed?
Emergency management officials from Polk County working with area emergency dispatch centers as well as law enforcement, fire departments, and other public safey officials developed the guidelines together in cooperation with the National Weather Service. Input on the draft guidelines was also sought from municipal and county officials from across the Polk County / Des Moines Metro Area. During the fall of 2009, the final guidelines were shared with community governments for implementaion.
Has my community adopeted the guidelines?
Support across the area for a unified outdoor warning system policy has been extremely strong. Within a few months of distribution, the guidelines were formally adopted by the Polk County Emergency Management Commission and supported by the Polk County Shreff's Communications Center, the Des Moines Police and Fire Dispatch Center, and the WestCom Dispatch Center. These three 911 Communications Centers collectively cover all of Polk County and the cities within Polk County.
How can I get alerts when I'm at work or in my house?
For alerts indoors, every home and business should have a NOAA All-Hazards Radio. NOAA Radio is like a smoke detector for severe weather, and it can wake you up when a warning is issued for your area so you can take appropriate action.
Will the sirens warn me of every dangerous storm?
The safest approach is to be proactive and use all of the information available to protect yourself and your family from threatening weather. Nothing can replace common sense. If a storm is approaching, the lightning alone is a threat. Sirens are only one part of a warning system that includes preparation, NOAA All-Hazards Radio, and the local media.
Where can I read the guidelines?
The outdoor warning siren guidance document and other information are available on the Polk County Emergency Management Agency website at:
Who activates the sirens?
Sirens are typically activated by city or county officials, usually the 911 communications center. Depending upon your location in Polk County this mayt be the Polk County Sheriiff's Communications Center, the Des Moines Police and Fire Dispatch Center, or the WestCom Dispatch Center.
Who do I contact if the siren in my neighborhood is not working?
If your siren is not functioning properly you should contact the Polk County Emergency Management Agency at 515-286-2107. They will need to know the siren location and description of the problem in order to direct the maintenance / repair request ot the proper jurisdiction.
How can I get more information?
Polk County Emergency Management:
NOAA All-Hazards Radio:
For additional supporting information, please refer to:
Outdoor Warning Siren Activation Quick Reference Guide
Outdoor Warning Siren Activation Guidelines
Sirens - Frequently Asked Questions