To alert the public of a severe weather threat. Threats generally include tornado and severe weather warnings, hail over 1.25 inches and straight-line winds 70 mph or higher. The primary function of the sirens is to notify people outside of an imminent weather threat. The criterion for utilization depends on the storm track. Depending on your proximity to a siren location, it may be heard indoors; however, the system is not intended for that specific purpose.