Dangerous weather — not just tornadoes — means warning sirens

As we head towards spring — and, unfortunately, tornado season — the City of North Liberty would like to remind residents about outdoor weather sirens, who sounds them and under what conditions.
While North Liberty’s seven sirens are owned and maintained by the city, the Johnson County Joint Emergency Communications Center, staffed 24 hours a day, seven days a week, sounds the sirens in accordance with guidelines written by the Johnson County Emergency Management Agency.
While many think of the outdoor warning sirens as “tornado sirens,” the sirens are sounded for other severe weather to alert those who are outside that something dangerous is approaching, and they need to seek shelter indoors.
The sirens are sounded under the following conditions:

• Tornado warnings, either Doppler radar indicated or reported by a trained spotter
• Severe thunderstorms warnings with winds of 70 mph or greater
• Severe thunderstorms warnings with golf-ball-sized hail or larger

Keep in mind that the same tone is used for all weather-related threats throughout the county, and that the sirens may be sounded multiple times to convey a continued or new threat. However, the county does not sound an all-clear, with the expectation that those indoors will be monitoring the weather through an all-hazards weather radio and the local media.
Sirens county-wide are tested on the first Wednesday of each month at 10 a.m.
For more information on Johnson County’s outdoor warning system, refer to this PDF.