POLK COUNTY, Iowa -- Many people in western Polk County heard sirens Sunday night, but didn't see rain or wind until much later.
That's because the policy is to sound the sirens for three to five minutes, every 15 minutes for the duration of a weather warning.
On Sunday, Dallas County was under a warning beginning at 8:00 p.m. and lasting until 9:00 p.m. That included parts of West Des Moines, Clive, and Urbandale.
But, because parts of those cities are also in Polk County, sirens went off in areas that weren't under the warning. Polk County Emergency Management says the sirens are important, but shouldn't be the only warning system people rely on during severe weather.
"I would say to people, do not use the outdoor warning sirens as your only single point of resource for understanding what is going on. Please go inside, seek additional information from the TV, the radio or any of the severe weather apps on your phone to find out exactly what is going on,” says Samantha Brear with Polk County Emergency Management.
The sirens sound for tornado threats and winds of more than 70 miles-per hour.