From the City of Grand Island:

In an effort to maintain a reliable outdoor public warning system, the Grand Island/Hall County Emergency Management Department secured a Federal Emergency Management Association (FEMA) Hazard Mitigation Grant to fund the replacement of older and failing devices with newer sirens featuring a wider effective range.

The Hazard Mitigation Grant Program (HMGP) provides grants to state and local governments to implement long-term hazard mitigation measures after a major disaster declaration.

The purpose of the HMGP is to reduce the loss of life and property due to natural disasters and to enable mitigation measures to be implemented during the immediate recovery from a disaster. The HMGP is authorized under Section 404 of the Robert T. Stafford Disaster Relief and Emergency Assistance Act.

The Emergency Management Department maintains and operates 38 sirens in each of the incorporated communities of Hall County. These devices are activated remotely by the Grand Island Emergency Center (GIEC).

Hall County tests all outdoor warning devices on the first and fifteenth day of every month at 1 p.m. These devices feature two distinct tones:
Alert (Long) Tone: A long, solid tone is used for weather emergencies.

Attack (Warble) Tone: A warble tone which wavers up and down is employed for civil emergencies.

Depending on the siren, these devices have a range between approximately 800 and 6,200 feet at 70db or more. The effectiveness of any outdoor warning device is influenced by external forces such as noise from wind, rain, hail, and thunder.

The Emergency Management Department would like to remind citizens that outdoor warning devices are specifically designed for outdoors and are not an effective or reliable indoor warning device. Families and business are strongly encouraged to monitor any of the warning systems listed above inside a structure.