Sign up for Johnson County Emergency Notification System

The State of Iowa and all counties within have changed the high-speed reverse 911 telephone emergency notification service effective 7/1/2021 to Rave Mobile.  The system is known statewide as Alert Iowa and replaces the previous two systems used known as (Johnson County Emergency Notification System “JCENS”) to the new Alert Iowa system provided by Rave Mobile.

This notification system for mass public safety alerts is a free opt-in service for Johnson County residents. During an emergency, the system delivers mass voice, text, and email messages to registered phones and email addresses. The system allows dispatchers and emergency managers to notify the entire county or specific areas of an evacuation, lost or missing person, or other type of public safety threat.

The new system also sends alerts to email and text-capable cell subscribers for specific hazardous weather threats issued by the National Weather Service: Severe Thunderstorm Warnings, Tornado Warnings, Flash Flood Warnings, Ice Storm Warnings, and Blizzard Warnings. The system can provide desktop popup alerting for government buildings within Johnson County.

Sign up now 

Subscribe to Alert Iowa to receive emergency notifications

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For additional information, contact Dave Wilson, Johnson County Emergency Management Agency Director, at 319-356-6761.

Weather alert system

The weather alert system is operated by the Johnson County Emergency Management office. Sirens within the city limits of Iowa City are owned and maintained by the Iowa City Fire Department. The sirens are intended to give persons who are outdoors a warning of possible tornados or other severe weather. Upon hearing the sirens, individuals who are outdoors should seek cover. More specific information can then be acquired through local television or radio stations, or through weather alert radios. The Johnson County Emergency Management office strongly suggests that people equip their homes with a weather alert radio to have accurate information and an alert in the home.

What the outdoor weather alert system means to you

  1. A weather warning means that a tornado, straight line winds in excess of 70 MPH or other possibly disastrous occurrence has been spotted and reported by radar, weather spotters, or other trained weather spotters.
  2. The sirens are sounded on those reports by and the systems are activated countywide by the Countywide 911 center known as the Joint Emergency Communications Center (JCOM/JECC), according to standard operating procedures which follow NOAA best practices adopted by most Counties in Iowa.
  3. Sirens in Johnson County are activated by the zone where the warning exists and sometimes countywide.
  4. No counties in Iowa sound an "all clear" signal using their outdoor sirens nor is this a NOAA best practice to do so.
  5. Additional outdoor siren activations are an indication that there is an additional severe weather occurrence in the area or that the warning has been extended.
  6. All sirens in Johnson County are tested at 10 a.m. on the first Wednesday of each month except when threatening weather conditions exist that would cause confusion.
  7. The public may also call to confirm whether the siren performed as programmed or did not sound and are asked to call and report any malfunctions of sirens on test days.

One final reminder: It must be stressed that the outdoor sirens are just what the name implies: an "outdoor warning device."  Its primary purpose is to alert those who are outdoors to move indoors, at which point they can receive more specific weather information through local television or radio stations, or through weather alert radios.

For more information, contact:

Johnson County Emergency Management

Dave Wilson, Coordinator
4529 Melrose Avenue
Iowa City, IA 52246

Weather Alert Siren Locations


These are links to other federal and state agencies which provide useful information for emergency preparedness.