The City of Johnston is working to determine why a few of the Outdoor Warning Sirens System did not sound in all locations during yesterday’s storm. During the week of May 18, four of the Outdoor Warning Sirens within our community were replaced (5604 NW 87th Street, 5501 NW 57th Avenue, 7001 NW Beaver Drive, and 8406 NW 78th Avenue). Polk County dispatch sounds the Outdoor Warning Sirens in the event of severe weather meeting the requirements in the Polk County-Wide Outdoor Warning Siren Activation Policy.
City staff is working with Polk County to determine if the tone to activate the sirens was not recognized during yesterday’s severe weather. Crews were on site this morning, inspecting the sirens and the battery back-ups on each of the systems. Our Outdoor Warning Siren vendor will be onsite on Wednesday, May 27, to review the issue.
The storm from Monday, May 25, is unique as it formed rapidly over or just upstream from Terra Park. Tornado Warnings are issued based on two primary sources of information – the radar and/or reliable reports of occurrence (first responders and trained spotters). In the storm event from last evening, both were received nearly simultaneously as the tornado rapidly developed. Once the threat is identified and the decision to warn has been made, it takes one to two minutes to create the warning and reach the dissemination (television, radio, and mobile phones).
All of Johnston’s Outdoor Warning Sirens work on manual activation. Severe weather is in the forecast for this afternoon and evening, and if needed, city crews will activate the sirens manually. We will continue to work with Polk County regarding the Outdoor Warning Siren System in our community as the safety of our residents is our top priority.
Weather dependent, the Outdoor Warning Sirens will be tested on Wednesday, May 27. Please do not call 9-1-1 during the test. All information regarding the test will be supplied by Polk County Emergency Management on their website and Facebook page.